Author	Topic:   Climate
Climate Change (Moderator)	posted 8/1/03 11:37 AM     Climate Change
Climate Change (Moderator)	posted 8/1/03 11:43 AM     Europe's Heat Wave Raises Global Warming Concerns Thu Jul 31, 2:31 PM ET By Adrian Croft MADRID (Reuters) - The intense heat wave that has baked much of Europe for weeks, fueling deadly forest fires, causing drought and damaging crops, has convinced many people that global warming is a reality. While experts caution that you cannot read too much into a single hot summer or natural disaster, Europe does seem to be experiencing extreme weather with growing frequency. Less than a year ago, scores of people were dying as floods swamped Germany, Russia, Austria and the Czech Republic. This year, the problem is extremely hot weather and drought, which, though it might be welcome to holidaymakers, is threatening lives and livelihoods in many parts of Europe. "We've not seen such an extended period of dry weather and sunny days since records began (in about 1870)," said Michael Knobelsdorf, a meteorologist at the German weather service, referring to Europe as a whole. "What's remarkable is that these extremes of weather are happening at such short intervals which suggests the climate is unbalanced. Last year in Germany, we were under water. Now we have one of the worst droughts in human memory," he said. He urged caution about blaming everything on greenhouse gases that many experts believe cause global warming, although he said indications are that temperatures are up one to two degrees Celsius over the past century. Much of Europe, from Scandinavia to the Mediterranean and Britain to central Europe, has sweltered through unusually long heat waves recently. DEADLY FIRES Forest fires have hit France, Portugal, Russia and Croatia. Four tourists were killed in fires on the French Riviera this week that forced thousands to flee villas and campsites. The hot weather is also taking its toll on agriculture, with forecasts for cereal production in Germany and the EU being cut. In most parts of Italy, temperatures have hovered around the mid-30s Celsius every day for two months, with Milan hitting a June record of over 40 degrees Celsius. The heat wave has pushed Italy's electricity grid to its limit as people crank up their air conditioners, leading to rolling blackouts that have affected millions of Italians. Drought has caused billions of euros in crop damages. The chief climatologist at Italy's National Geophysics Institute said the searing temperatures were further evidence of global warming, but did not provide a "smoking gun." Antonio Navarra said the whole Mediterranean region was two to three degrees warmer than usual this summer and if the heat persisted, it would be consistent with the institute's climate simulations showing the potential effect of greenhouse gases. Paul Horsman, a climate campaigner with environmental group Greenpeace International, said that while scientists believed a heat wave could not be directly linked to climate change, "when you get a range of events there is certainly evidence that we are living in a globally-warmed world." "We would argue very strongly that these events we are seeing are consistent with what the scientists are saying about climate change," Horsman said, adding that they reinforced the need for strong measures to curb climate change. The Dutch KNMI meteorological institute said the maximum temperature in the Netherlands was 35.8 degrees in July and the average 18.8, against a normal summer average of 17.4 degrees. "It looks like this summer is set to take the record from the summer of 1947," a KNMI meteorologist said. The Norwegian coastal town of Bergen, known for rain rolling in from the north Atlantic, has had its warmest summer since 1925 with an average July temperature of 18 degrees Celsius. In Finland, there have been only a couple of slightly cooler days since the heat wave began on July 14. Temperatures in Spain forecast to peak at 45 degrees Celsius in the south on Thursday led people to complain of sleeplessness and authorities to warn against too much time in the sun. (Additional reporting by Philip Blenkinsop in Berlin, Shasta Darlington in Rome, Marcel Michelson in Amsterdam, John Acher in Oslo, Nina Garlo in Helsinki) Copyright © 2003 Yahoo! Inc. All rights reserved.
Ozone Depletion Slowing	posted 8/1/03 12:30 AM     Scientists Say Ozone Depletion Slowing Wed Jul 30,10:48 AM ET WASHINGTON - The rate of destruction of the protective ozone layer in the upper reaches of the atmosphere is slowing, and scientists say it mirrors a decline in the use of certain man-made chemicals. Using NASA satellite observations, the scientists say the rate of the ozone layer depletion matches the drop in chlorofluorocarbons, used in refrigeration and air conditioning. The 1987 Montreal Protocols, ratified by more than 170 countries, requires that CFCs be phased out of production and use in developing countries by 2010. Industrialized nations stopped using them in 1996. Scientists said that it will take decades to repair the damage to the ozone layer, which helps protect the Earth from ultraviolet radiation from the sun. "Ozone is still decreasing but just not as fast," said Mike Newchurch, associate professor at the University of Alabama and lead scientist on the study. "We are still decades away from total ozone recovery." On the Net: Ozone research: http://oea.larc.nasa.gov/news_rels/2003 Copyright © 2003 The Associated Press. All rights reserved.
Glaciers Melting	posted 8/1/03 1:08 PM     February 19, 2001 Glacier Loss Seen as Clear Sign of Human Role in Global Warming By ANDREW C. REVKIN Ohio State University The glacier Qori Kalis in the Peruvian Andes, pictured at top in 1983 and at bottom in 2000. The melting rate of the glacier has increased in the last 25 years, scientists say, and since 1998 has vastly accelerated. The icecap atop Mount Kilimanjaro, which for thousands of years has floated like a cool beacon over the shimmering plain of Tanzania, is retreating at such a pace that it will disappear in less than 15 years, according to new studies. The vanishing of the seemingly perpetual snows of Kilimanjaro that inspired Ernest Hemingway, echoed by similar trends on ice-capped peaks from Peru to Tibet, is one of the clearest signs that a global warming trend in the last 50 years may have exceeded typical climate shifts and is at least partly caused by gases released by human activities, a variety of scientists say. Measurements taken over the last year on Kilimanjaro show that its glaciers are not only retreating but also rapidly thinning, with one spot having lost a yard of thickness since last February, said Dr. Lonnie G. Thompson, a senior research scientist at the Byrd Polar Research Center of Ohio State University. Altogether, he said, the mountain has lost 82 percent of the icecap it had when it was first carefully surveyed, in 1912. Given that the retreat started a century ago, Dr. Thompson said, it is likely that some natural changes were affecting the glacier before it felt any effect from the large, recent rise in carbon dioxide and other heat- trapping greenhouse gases from smokestacks and tailpipes. And, he noted, glaciers have grown and retreated in pulses for tens of thousands of years. But the pace of change measured now goes beyond anything in recent centuries. "There may be a natural part of it, but there's something else being superimposed on top of it," Dr. Thompson said. "And it matches so many other lines of evidence of warming. Whether you're talking about bore- hole temperatures, shrinking Arctic sea ice, or glaciers, they're telling the same story." Dr. Thompson presented the fresh data yesterday at the annual meeting of the American Association for the Advancement of Science in San Francisco. Other recent reports of changes under way in the natural world, like gaps in sea ice at the North Pole or shifts in animal populations, can still be ascribed to other factors, many scientists say, but many add that having such a rapid erosion of glaciers in so many places is harder to explain except by global warming. The retreat of mountain glaciers has been seen from Montana to Mount Everest to the Swiss Alps. In the Alps, scientists have estimated that by 2025 glaciers will have lost 90 percent of the volume of ice that was there a century ago. (Only Scandinavia seems to be bucking the trend, apparently because shifting storm tracks in Europe are dumping more snow there.) But the melting is generally quickest in and near the tropics, Dr. Thompson said, with some ancient glaciers in the Andes — and the ice on Kilimanjaro — melting fastest of all. Separate studies of air temperature in the tropics, made using high- flying balloons, have shown a steady rise of about 15 feet a year in the altitude at which air routinely stays below the freezing point. Dr. Thompson said that other changes could also be contributing to the glacial shrinkage, but the rising warm zone is probably the biggest influence. Trying to stay ahead of the widespread melting, Dr. Thompson and a team of scientists have been hurriedly traveling around the tropics to extract cores of ice from a variety of glaciers containing a record of thousands of years of climate shifts. The data may help predict future trends. The four-inch-thick ice cylinders are being stored in a deep-frozen archive at Ohio State, he said, so that as new technologies are developed for reading chemical clues in bubbles and water in ancient ice, there will still be something to examine. The sad fact, he said, is that in a matter of years, anyone wanting to study the glaciers of Africa or Peru will probably have to travel to Columbus, Ohio, to do so. Dr. Richard B. Alley, a professor of geosciences at Pennsylvania State University, said the melting trend and the link — at least partly — to human influence is "depressing," not only because of the loss of data but also because of the remarkable changes under way to such familiar landscapes. "What is a snowcap worth to us?" he said. "I don't know about you, but I like the snows of Kilimanjaro." The accelerating loss of mountain glaciers is also described in a scientific report on the impact of global warming, which is being released today in Geneva by the Intergovernmental Panel on Climate Change, an influential network of scientists advising world governments under the auspices of the United Nations. The melting is likely to threaten water supplies in places like Peru and Nepal, the report says, and could also lead to devastating flash floods. Kilimanjaro, the highest point in Africa, may provide the most vivid image of the change in glaciers, but, Dr. Thompson said, the rate of retreat is far faster along the spine of the Andes, and the consequences more significant. For 25 years, he has been tracking a particular Peruvian glacier, Qori Kalis, where the pace of shrinkage has accelerated enormously just in the last three years. From 1998 to 2000, the glacier pulled back 508 feet a year, he said. "That's 33 times faster than the rate in the first measurement period," he said, referring to a study from 1963 to 1978. In the short run, this means the hydroelectric dams and reservoirs downstream will be flush with water, he said, but in the long run the source will run dry. "The whole country right now, for its hydropower, is cashing in on a bank account that was built up over thousands of years but isn't being replenished," he said. Once that is gone, he added, chances are that the communities will have to turn to oil or coal for power, adding even more greenhouse gases to the air. The changes in the character of Kilimanjaro are registering beyond the ranks of climate scientists. People in the tourism business around the mountain and surrounding national park are worried that visitors will no longer be drawn to the peak once it has lost its glimmering cap. Dr. Douglas R. Hardy, a geologist at the University of Massachusetts, returned from Kilimanjaro last Thursday with the first yearlong record of weather data collected by a probe placed near the summit. Just before he left, he had a long conversation with the chief ranger of Kilimanjaro National Park, who expressed deep concern about the trend. "That mountain is the most mystical, magical draw to people's imagination," Dr. Hardy said. "Once the ice disappears, it's going to be a very different place." And the melting continues. When Dr. Hardy climbed the mountain to retrieve the data, he discovered that the weather instruments, erected on a tall pole, had fallen over because the ice around the base was gone.
Record Chinese Heatwave (Moderator)	posted 8/2/03 9:35 AM     Saturday August 2, 07:23 AM Chinese officials resort to untraditional means amid 50-year heat wave BEIJING (AFP) - East China is sweating through its longest heat wave in 50 years -- some of it paradoxically caused by air conditioners -- as officials adopt untraditional means to save energy, state media said. In China's largest city Shanghai, the mercury has hovered above 35 degrees Celsius (95 degrees Fahrenheit) for a record-challenging 14 days, putting pressure on the already strained power supply, Xinhua news agency reported. Residents' wish to keep cool is partly to blame, as the growing use of electric air conditioners has been generating added heat, the agency quoted meteorologists as saying. To save power, municipal authorities have announced they will suspend all scenic lighting beginning from Tuesday. The high temperatures are also being felt in the nearby city of Hangzhou, where officials have resorted to incentives to lower power demand. The government is now paying a total of 150,000 yuan (18,000 dollars) a day to 100 large companies to halt evening operations, according to Xinhua. Government staff are also being told to go home early, leaving only skeleton crews and security workers to man their offices in the evenings, the agency said. http://www.geocities.com/iona_m Author's website
Record European Heatwave (Moderator)	posted 8/13/03 9:32 AM     New Scientist | AFP Wednesday August 13, 12:49 AM Europe's heatwave sears its way into the record books PARIS (AFP) - A heatwave that has set all-time record temperatures in many countries pushed much of Europe to the brink, overloading power plants, filling hospitals and fuelling new forest fires while governments struggled to cope. In France, where doctors say the heat alone has already claimed more than 100 lives, Prime Minister Jean-Pierre Raffarin announced that beds would be made available to the public in military hospitals to cope with an influx of patients with heat-related complaints. The move came after doctors warned that the heatwave had become a serious public health crisis, and criticised the government for reacting too slowly, triggering an intense political debate. "We've got more than 100 victims," said Patrick Pelloux, the head of France's association of emergency doctors. French Health Minister Jean-Francois Mattei, in an interview on TF1 television, refused to confirm Pelloux's figures, but said: "What is clear is that I don't want to speak about deaths from natural causes, because the heat is a triggering factor." France on Tuesday recorded its highest temperature since the heatwave began, with the mercury rising to 42.6 degrees Celsius (108.8 Fahrenheit) in the southeastern town of Orange. The last time such a high temperature was registered in France was in the summer of 1982, when the southeastern town of Luc recorded 42.7 degrees Extremely low water levels and steep demand from overworked air conditioners have forced French and German authorities to relax temporarily the operating rules governing power stations -- particularly those with nuclear reactors -- to stave off blackouts. Forecasters said that northern Europe would likely see a respite Thursday and Friday, although temperatures may well rise again afterwards and southern Europe would continue to swelter. The number of dead linked to the baking weather and fast-moving forest fires has continued to rise, though no firm tally was available. At least 28 people are known to have died in Europe from heat-related complaints in the past 11 days -- 24 in Spain, two in northern France and two in Italy -- but heat is the suspected cause of dozens more deaths, if not hundreds. Another 25 people have been killed by forest fires -- five in France, 15 in Portugal and five in Spain -- that have devastated hundreds of thousands of hectares of land. Blazes raged out of control Tuesday in Portugal, threatening tourist areas in southern Algarve province. Portugal has suffered the highest temperatures, recording a mighty 47.3 degrees Celsius (117.1 degrees Fahrenheit) on August 1 in Amarelejo, on the Spanish border -- the hottest temperature since records began in 1856. New all-time highs were also recorded in Germany, Italy, Spain, Austria and often-gloomy Britain, where bookmakers were forced to pay out hundreds of thousands of pounds (euros, dollars) after the mercury topped 100 degrees Fahrenheit (37.8 Celsius) at the weekend. British environmentalists on Tuesday rescued over 1,000 fish -- including rare brown trout and minnows -- from a river that was fast drying up in the county of Hertfordshire, north of London. French state-owned power utility EDF meanwhile said it had closed a coal-driven plant outside Paris because it could no longer meet environmental standards. The head of EDF Francois Roussely said his company was seeking to import energy to meet demand, but said blackouts should be averted for the rest of the week. "The heatwave has hit all European countries and all means of production," he said. The hot weather combined with months of severe drought has also left Europe's farmers in dire straits, with grain yields across the European Union expected to fall 5.7 percent from last year to 197 million tonnes, according to farm lobbies. Companies are also paying a price as overheated computers malfunction and erase valuable information on their hard drives, according to Spanish computer firm Recovery Labs, which said one in three firms had experienced data loss during the hot spell. Yet the blazing sun has brought consolation for some. The tourist industry in coastal areas has been booming; winegrowers in France and Germany are expecting to begin a quality harvest several weeks earlier than usual; and makers of sun creams, refrigerators and air conditioning units have had one of their busiest seasons ever. http://www.geocities.com/r_ayana/AdrenalineRush.html Author's website
Europe's Largest Glacier Melts (Moderator)	posted 8/16/03 9:39 AM     New Scientist | AFP Saturday August 16, 06:12 AM Europe's largest glacier shrivels under global warming Click to enlarge photo RIEDERALP, Switzerland (AFP) - Switzerland's Aletsch glacier, the largest in the Alps, is imposing enough to generate a wind of its own, but the 23-kilometre long (14-mile) river of ice is visibly shrivelling under the impact of global warming. "In the last 140 years it has moved back three kilometres (two miles)," Laudo Albrecht, a Swiss nature conservation expert said, standing on a ridge above the sweating glacier. He was clutching a graph which also shows that the ice flow has melted faster in the past decade or two, and this summer's heatwave is likely to deepen the trend. The Aletsch and the immediate area were designated a World Heritage site in December 2001, not only because of the spectacular nature of the landscape of rocky peaks, wooded slopes, meadows and glaciers, according to UNESCO. The UN's Educational, Scientific and Cultural Organisation also explained that "the global phenomenon of climatic change is particularly well illustrated in the region". Albrecht pointed across the valley to a contrasting band of colour along the opposite slope, like a trace of grime on an emptied bath. It shows that the Aletsch has lost about 200 metres (660 feet) in depth along most of its length since the 1860s. The layer of ice is now 100 to 150 metres thick near the foot of the glacier, below the southern Swiss mountain village of Riederalp. "This summer fits the developments of the past decade, that's what worries me. Not that this summer is so hot or dry, but because it fits this trend," Albrecht, who has been observing the glacier for 20 years, said. Switzerland has been ailing under record high temperatures for more than two months, with a peak over 41 degrees Celsius (106 Fahrenheit). Despite the cool wind generated by the huge mass of the glacier, the temperature at an altitude of 2,000 metres (6,600 feet) hovered around 25 degrees Celsius (77 Fahrenheit) in the shade. Albrecht set foot on the Aletsch for the first time this year on June 10. He returned a month later and found that the end of the ice flow had retreated five metres (16 feet) further up the valley. On the steep slopes around Riederalp, farmers are struggling to comfort their cows. Sprinklers create patches of green among the parched Alpine meadows. The herds amble along mountain tracks, sending clouds of dust billowing in the air, and gather around water holes. Albrecht, who was born and raised in this hardy, mountainous region, heads an information centre set up by the Swiss nature conservancy foundation, Pro Natura, in Riederalp. He is the first to point out that exceptional weather has happened before, and insists that he always highlights the wonders of nature before he mentions the stresses and strains to visitors. Yet, he now firmly believes that climate change is not simply a natural phenomenon, but that a human hand -- pollution -- is helping it along. "If you want to change people's behaviour, you need time. The question I now ask myself is, do we have enough time?" Albrecht commented. "We've had extremes like this before, to some degree it's a normal part of nature. But what disturbs me is that we have extremes frequently now, in some years storms, or other years without rain." Swiss authorities have warned that the hot, dry conditions have triggered landslides and rockfalls, and made conditions for mountaineers even more precarious. Albrecht sees another danger. When thunderstorms return and rain starts to fall again on the hardened ground, torrents will sweep loose material down into the inhabitated valleys below. In 1993, the nearby town of Brig was hit by a torrent of mud and rock carried by a river, cloaking the streets in a deep layer of hardened mud and killing two people. "It's profoundly disturbing, our living environment is being changed. Nature can live with that, but the question is, can we?" Albrecht observed. This summer, the increased flow of water from the melting ice is exceeding the needs of hydroelectric power plants. A dam below the Aletsch is opened occasionally to stop it overflowing, according to Albrecht. That can bring dangers: two tourists were killed recently on a nearby river bed after water was released upstream. It can also bring short-term benefits: local Swiss power companies are exporting electricity to Italy, less than 20 kilometres (12 miles) away, where record low water levels in rivers caused by the heatwave have prompted power cuts. Yet even those who have the most to gain from the power trade do not think it is worth it. "With the glaciers, our future capital is melting," an executive for the power firm EOS told the Swiss newspaper Le Temps. Copyright © 2003 AFP. All rights reserved. http://gonow.to/art submitters website
Europe's Harvest Matches Greenhouse predictions (Moderator)	posted 8/21/03 11:58 AM     New Scientist | AFP Wednesday August 20, 08:14 PM Europe's bizarre harvest mirrors climate-change prediction: New Scientist PARIS (AFP) - Shifting harvests in Europe this year, triggered by extreme but local bouts of rain, heat and drought, eerily foreshadow predictions made last year that warn global warming will reshape European agriculture, New Scientist says. Statistics issued this month by the European Commission's Joint Research Centre in Brussels say crop yields have shrivelled across southern Europe just as they have soared in northern Europe. High temperatures and water shortages have cut maize (corn) and sugar beet yields in drought-stricken Italy by a quarter, and wheat yields in Portugal have tumbled by a third. In Ireland, though, warm weather has boosted yields of sugar beet by a quarter and by up to five percent in Denmark and Sweden. Production of rapeseed, also called colza, has risen by 12 percent in normally cool Finland. The shift in productivity "is almost exactly" what was forecast last year by a pair of soil experts, Jorgen Olesen of the Danish Institute of Agricultural Sciences and Marco Bindi of Italy's University of Florence, the British weekly notes in next Saturday's issue. In research published in the European Journal of Agronomy last year, they predicted farmers in northern Europe would enjoy bumper harvests thanks to wetter weather and higher levels of carbon dioxide (CO2), the fossil-fuel gas that drives global warming as well as plant photosynthesis. In southern Europe, though, higher temperatures and less rainfall would cut into crop yields, threatening the very existence of agriculture in the most parched regions, Olesen and Bindi maintained. Their forecast, however, was based on a computer modelling of likely CO2 levels in 2050 and was not intended as a prediction for the immediate future. Data collated by the United Nations' top scientific panel and global warming point to a succession of ever hotter years in the last quarter of the 20th century, and a steady rise in global temperatures in the 21st century. Scientists are generally loth to say that these temperatures have already initiated a change in the world's climate, arguing only that a longer view, spanning decades, can confirm the hypothesis or not. However, that consensus has begun to crumble in recent years in the light of extreme weather events in Europe, the United States and elsewhere, and some experts are now openly suggesting the system is showing signs of man-made change. (Copyright © 2003 AFP. All rights reserved. http://gonow.to/resonance submitters website
2003 Ozone Layer Hole (Moderator)	posted 8/22/03 12:42 AM     2003 Ozone Hole May Be Record Size, Australia Says Fri Aug 22, 2:57 AM ET By Michael Perry SYDNEY (Reuters) - The ozone hole over the Antarctic is growing at a rate that suggests it could be headed for a record size this year, Australian scientists said on Friday. A study by Australian Antarctic bases attributed the development to colder temperatures in the stratosphere where the ozone hole forms. "The growth at the moment is similar to 2000 when the hole was a record size," Australian Antarctic Division scientist Andrew Klekociuk told Reuters on Friday. Ozone is a protective layer in the atmosphere that shields the Earth from the sun's rays, in particular ultraviolet-B radiation that can cause skin cancer, cataracts and can harm marine life. In 2000, NASA (news - web sites) said the ozone hole expanded to a record 10.9 million square miles, three times the size of Australia or the United States, excluding Alaska. "This is in contrast to the situation in 2002 when unusually warm conditions produced the smallest ozone hole since 1988," Klekociuk said. The ozone hole in 2003 presently covers all of the Antarctic. Klekociuk said scientists at Australia's Davis Antarctic base saw the first signs of cooling of the lower stratosphere, 15 to 25 km (nine to 15 miles) up, about six weeks earlier than usual. In a visual sign the ozone hole would grow rapidly this year, scientists at Australia's Mawson base have reported the early appearance of stratospheric clouds, which create a spectacular lightshow by defracting sunlight around sunset. Chemical reactions in these clouds convert normally inert man-made chlorofluorocarbons (CFCs) into ozone destroyers. CFCs are commonly used as propellants in spray cans. The 1997 Kyoto treaty set in place a global process to reduce greenhouse gases which deplete the ozone layer, but the world's biggest polluter the United States has yet to sign. Clouds do not usually form in the stratosphere due to its extreme dryness, but during some winters temperatures become low enough to allow their formation. "In 2000 we didn't see the stratospheric clouds until the beginning of July. This year we saw them about the middle of May which is the earliest we have seen them," Klekociuk said. The full extent of the 2003 ozone hole will not be known until the end of September, as August and September are the coldest months for the South Pole. Temperatures begin to warm by early October and the ozone layer will then start to recover. -------------------------------------------------------------------------------- Copyright © 2003 Reuters Limited. All rights reserved. http://www.geocities.com/r_ayana/AdrenalineRush.html submitters website
Earth Hotter than Last 2000 Years (Moderator)	posted 9/3/03 12:39 AM     Last Updated: Monday, 1 September, 2003, 16:37 GMT 17:37 UK Earth hits '2,000-year warming peak' By Alex Kirby BBC News Online environment correspondent The Earth appears to have been warmer since 1980 than at any time in the last 18 centuries, scientists say. They reconstructed the global climate from data derived from ice cores, vegetation and other records. They believe their research provides unequivocal confirmation that humans are affecting the climate. But sceptics still insist that any human contribution is likely to be too small to explain what is happening. The scientists are Professor Philip Jones, of the climatic research unit, University of East Anglia, UK, and Professor Michael Mann, of the University of Virginia, US. Their study, published in the journal Geophysical Research Letters, supports recent findings from the Intergovernmental Panel on Climate Change. After studying temperature data from up to 1,000 years ago, the panel said the late 20th century had been the warmest period on record. To test the strength of claims that the world had in fact been warmer before 1000 AD, Professors Jones and Mann sought to reconstruct the global climate over the last two millennia. Frozen evidence They examined the trunks of ancient trees from different regions to compile a record of local conditions - the thickness of the trees' annual growth rings is determined by the climate. More grapes grow in UK now They also studied cores drilled from the icecaps of Greenland and Antarctica, examining the trapped air bubbles for information about the climate prevailing at the time the ice formed. A third source of information was historical records, especially from the Netherlands, Switzerland and China. The authors were unable to find enough information to work out what the southern hemisphere's climate had been, but are satisfied their conclusion that the northern half of the planet is in the warmest period of the last 2,000 years is robust. While some parts of the Earth may have been warmer than they are now, they say, average temperatures were cooler. They say the Earth has warmed by at least 0.2C in the last 20 years or so - the amount by which it has warmed or cooled over the space of a century in the past. Fingering the Sun Professor Jones said: "It just shows how dramatic the warming has been in recent years. You can't explain it in any other way - it's a response to a build-up of greenhouse gases in the atmosphere." The Vikings cared little for climate Some scientists believe the recent temperature increases are explained by solar radiation, with emissions of carbon dioxide and other greenhouse gases too small to account for the changes observed. Others say the historical record proves the climate fluctuates naturally, with human influence irrelevant to global trends. To the argument that northern Britain was warm enough 1,000 years ago for vineyards to flourish, the authors say there are far more now. Seeing the whole They say the Vikings' voyage from Iceland to Greenland in 980 AD was a quest for land, not for a warmer climate. They also reinterpret the fact that the river Thames used to freeze over more often, saying the design of the original London Bridge affected the river and made it freeze more easily. Professor Jones told BBC News Online: "The climate sceptics are flogging a dead horse. You can't say the whole world was once warmer than it is now just because Europe was warmer. "You have to aggregate the records together, as we've done. We'd like more records, especially from the tropics - but we do think we have enough information to say the world is now warmer than it's been for 2,000 years." http://groups.yahoo.com/group/askmartian ask the martian anything
greenhouse gases at record levels (Moderator)	posted 9/3/03 12:49 AM     Tuesday, 11 February, 2003, 16:16 GMT Greenhouse gases 'at record levels' By Alex Kirby BBC News Online environment correspondent British scientists say greenhouse gases are at the highest background levels ever recorded in the atmosphere. They say stabilising the amount of atmospheric carbon dioxide (CO2) will be harder, because a warming world will trigger feedback mechanisms. Their report says the UK exceeded its international target for cutting greenhouse emissions by 2000. The UK Government says the scientists' findings show much more needs to be done to reduce emissions. The report, the Global Atmosphere Research Programme 2000-2002, is published by the Department for Environment, Food and Rural Affairs (Defra). More to do It provides the results of Defra's research programme on climate change and stratospheric ozone, based at the UK's Hadley Centre for Climate Prediction and Research. Climate will affect animal health Launching the report the Environment Minister, Michael Meacher, said: "This report does show that the UK is making good progress to tackle its greenhouse gas emissions. "But much more needs to be done if we are to stabilise concentrations in the atmosphere at a safe level. "However, this report does also show that the UK more than met our target under the United Nations Framework Convention on Climate Change (UNFCCC) to return emissions to 1990 levels by 2000. "And we are on track to exceed our Kyoto Protocol target of a 12.5% cut in emissions below 1990 levels by 2008-12." The report's key findings include: atmospheric concentrations of many greenhouse gases reached their highest-ever levels in 2001 the three hottest years on record were 1998, 2001 and 2002 positive carbon cycle feedbacks from forests and vegetation could sharply speed up future warming. A positive feedback occurs when warming sets off a further warming trend - when thawing permafrost, for example, releases a greenhouse gas action being taken in the UK could reduce its total greenhouse gas emissions to 23% below 1990 levels by 2010 the world's protective ozone layer should recover by mid-century. Mr Meacher said the world faced "a serious wake-up call". A second report says Defra has already made adaptation to climate change a reality in some areas, but needs to include it in long-term policy development. Defra is adapting flood policy The report, Climate Change: The Implications for Defra, is an audit carried out by a unit of the UK Department of Transport. It praises Defra for including climate change as a factor in flood management and water resources policies. But it says: "Climate change will need to be factored into the long-term development of a wide range of Defra's polices, including on agriculture, biodiversity and animal health." Caught in crossfire Mr Meacher's acknowledgement that the UK - government, industry, and the whole of society - needs to do much more to face up to climate change will be welcomed by scientists who argue for cuts of more than half in CO2 emissions over the next 50 years. Many of them remain doubtful that the UK will achieve its demanding target of cutting carbon emissions to 20% below their 1990 levels by 2010. His comments will provoke scepticism as well from those scientists and their supporters who argue that climate change remains unproven. http://groups.yahoo.com/group/askmartian ask the martian anything
Global Warning (Moderator)	posted 9/9/03 9:49 AM     www.newscientist.com Global warning 16:14 19 February 01 Climate scientists have for the first time formally warned that global warming could unleash catastrophic and irreversible changes to key planetary processes that make the world habitable. The possible changes are highlighted in a new report from the UN's Intergovernmental Panel on Climate Change, agreed in Geneva on Sunday. They include: • a slowdown in ocean circulation, which would cool Europe but accelerate warming in much of the rest of the globe; • runaway global warming as carbon dioxide and methane escape from melting permafrost and sediments on continental shelves; • the disintegration of the Greenland and West Antarctic ice sheets The report accepts that the likelihood of some of these events may be low. But it warns that the risks are "not well-known" and are "expected to increase with the rate, magnitude and duration of climate change". The report is the consensus finding of 700 scientists from more than a hundred countries, chaired by Osvaldo Canziani of Argentina and James McCarthy of the US. Climate surprises These fundamental shifts in planetary processes have been dubbed by scientists "climate surprises". They underline the growing realisation that the planet is likely to respond to global warming with a series of unpredictable shudders, rather than with smooth, predictable change. The "surprises" come on top of a series of high-probability changes, many of them already under way. The report's authors expect that the coming century will see extensive melting glaciers, worsening droughts, spreading mosquito-borne diseases, declining crop yields, the collapse of many ecosystems and widespread coastal flooding. Even with no sea-level rise, it warns, up to 200 million people could face flooding from coastal storms within 80 years. Hot and cold The changing climate of some regions may increase agricultural productivity and the millions of Russians, Mongolians and Chinese currently suffering an unusually cold winter may welcome the prediction that deaths from cold will fall. But billions more in the tropics face the prospect of many more deaths from heat stroke, as their countries are forecast to receive higher than average increases in temperature. While the world must curb the emissions that cause climate change, the report says that we now have no choice but to prepare "adaptation strategies" for these perils. The report, on the human impacts of warming, complements the findings of another IPCC working group last month on the science of climate change. More at: Scientists blame "most" climate change on human activity IPCC Working Group II: Climate Change 2001: Impacts, Adaptation, and Vulnerability Fred Pearce http://groups.yahoo.com/group/askmartian ask the martian anything
4000 Die in Italian Heatwave - 15,000 in France (Moderator)	posted 9/12/03 11:09 AM     New Scientist | AFP Thursday September 11, 10:10 PM Heatwave killed over 4,000 in Italy ROME (AFP) - The summer heatwave killed more than 4,000 elderly people in Italy, the country's health minister confirmed. Figures compiled by the Health Institute showed Thursday that an extra 4,175 Italians over 65 years of age died between July 16 and August 15, or a 14 percent rise over the same period last year. The number was only an early estimate and when figures through August 31 were compiled, the toll was expected to surpass the 5,000 mark, said Donato Greco, head of Italy's National Epidemiological Centre. Additional heatwave-related mortality was the strongest in Milan, Turin and Genoa, northern Italy's largest cities. For people over 75 years of age and compared to the same period last year, mortality surged by 108 percent (350 individuals) in Turin, 79.4 percent (316 individuals) in Genoa and 69.3 percent (314 individuals) in Milan. Health Minister Girolamo Sirchia said the typical heatwave victim suffered from a chronic condition, lived by themselves in small lodgings without any air-conditioning and had a low income. On August 21 Sirchia ordered an investigation into heat-related deaths with a view to putting together a series of preventive measures. At the time, Italian media estimated the number of heat-related deaths only at around 1,000. In Spain, the media have recently been querying the official figure of 107 extra deaths due to the heatwave, suggesting that the toll might be as high as 6,000. In France, the official toll was put at 11,435, but funeral directors said Tuesday the final figure would be around 15,000. http://groups.yahoo.com/group/askmartian ask the martian anything
Antarctic Vortex Makes Permanent Drought? (Moderator)	posted 9/24/03 12:44 AM     Science - Reuters Scientists See Antarctic Vortex as Drought Maker Tue Sep 23, 5:04 AM ET By Michael Byrnes SYDNEY (Reuters) - Australia may be facing a permanent drought because of an accelerating vortex of winds whipping around the Antarctic that threatens to disrupt rainfall, scientists said on Tuesday. They attribute the phenomenon to global warming and loss of the ozone layer over Antarctica. "This is a very serious situation that we're probably not confronting as full-on as we should," Dr James Risbey of the Center for Dynamical Meteorology and Oceanography at Melbourne's Monash University told Reuters on Tuesday. "There has been real added impetus here in Australia to try to study (the wind vortex) because we've been faced with an almost precipitous rainfall decline, particularly in the southwest of Western Australia," Risbey said. Australia, one of the world's top agricultural supply nations, has just been through its worst drought in 100 years. Risbey and other Australians are part of an international band of scientists and meteorologists focusing on the vortex as an explanation for declining rainfall. Rainfall has declined by nearly 20 percent in the past seven years over parts of southwestern Western Australia, through to Victoria and into southern New South Wales state, Risbey said. At the same time, temperatures have been rising in Australia by about one degree Celsius over the past 50 years, requiring more rain to fall just to keep the status quo. SPINNING FASTER Australian scientists from the Bureau of Meteorology, the Commonwealth Scientific and Industrial Research Organization (CSIRO) and Monash University are working with the U.S. Office of Oceanic and Atmospheric Research and the British Antarctic Division on the Antarctic vortex. Focusing on the vortex for only the past few years, they have quantified increased velocity of the wind spin by measuring pressure differences between high latitudes over the Antarctic continent and mid latitudes in the Southern Ocean near Australia. A cooling polar area and warming elsewhere is spinning the vortex faster, which in turn pulls winds and pressure belts that deliver Australia's winter and spring rains southward. Australia's 2002/03 drought, the worst in 100 years and the cause of shortages of a wide variety of some of the world's largest supplies of bulk farm foods, was too extensive to blame on the Antarctic vortex. But a long-standing drought in the southwest corner of Western Australia state could be a foretaste of more extensive drought yet to come in Australia, Risbey said. Most worrying is that this could be more or less permanent, scientists say. Water resource managers were already treating the rainfall decline in southwest Western Australia as permanent. Melbourne was now in a seven-year drought, while New South Wales has had declining rainfall for the past 50 years or so, Risbey said. "It is consistent with...the polar vortex," he said. Scientists say Australian agriculture would be able to cope with a 15 percent to 20 percent drop in rainfall, although farmers may not agree. But changed management and consumption will be necessary, possibly not only in southern Australia but also in parts of South America, South Africa and New Zealand. http://story.news.yahoo.com/news?tmpl=story&cid=585&ncid=585&e=3&u=/nm/20030923/sc_nm/weather_australia_antarctic_dc
Largest Arctic Ice Shelf Breaks Up, Scientists Say (Moderator)	posted 9/24/03 1:44 PM     Science - Reuters Largest Arctic Ice Shelf Breaks Up, Scientists Say Mon Sep 22, 5:05 PM ET By Maggie Fox, Health and Science Correspondent WASHINGTON (Reuters) - The largest ice shelf in the Arctic, a solid feature for 3,000 years, has broken up, scientists in the United States and Canada said on Monday. They said the Ward Hunt Ice Shelf, on the north coast of Ellesmere Island in Canada's Nunavut territory, broke into two main parts, themselves cut through with fissures. A freshwater lake drained into the sea, the researchers reported. Large ice islands also calved off from the shelf and some are large enough to be dangerous to shipping and to drilling platforms in the Beaufort Sea. Local warming of the climate is to blame, they said -- adding that they did not have the evidence needed to link the melting ice to the steady, planet-wide climate change known as global warming. Warwick Vincent and Derek Mueller of Laval University in Quebec City, Canada, and Martin Jeffries of the University of Alaska Fairbanks lived at the site, flew over it and used radar satellite imaging for their study. Writing in the journal Geophysical Research Letters, Vincent's team said all of the fresh water poured out of the 20 mile long Disraeli Fjord. This in turn has affected communities of freshwater and marine species of plankton and algae, said Mueller, a graduate student who has studied the tiny creatures. Only 100 years ago the whole northern coast of Ellesmere Island, which is the northernmost land mass of North America, was edged by a continuous ice shelf. About 90 percent of it is now gone, Vincent's team wrote. The area has been getting warmer, they said. A similar trend in the Antarctic has caused the break-up of huge ice shelves there. "There's a regional trend in warming that cycles back 150 years," Mueller said in a telephone interview. "I am not comfortable linking it to global warming. It is difficult to tease out what is due to global warming and what is due to regional warming." Records indicate an increase of four-tenths of a degree centigrade every 10 years since 1967. The average July temperature has been 1.3 degrees Celsius or 34 degrees F -- just above the freezing point -- since 1967. Climate change has affected ocean temperature, salinity and flow patterns, which also influence the break-up of ice shelves in the Antarctic. "It's not just as simple as it gets x degrees warmer and the ice melts this much," Mueller said. Warmer temperatures weaken the ice, leaving it vulnerable to changed currents and other forces. http://story.news.yahoo.com/news?tmpl=story2&u=/nm/20030922/sc_nm/environment_arctic_dc&e=6&ncid=585
Europe had hottest summer for at least 500 years (Moderator)	posted 9/24/03 2:16 PM     Science - AFP Europe had hottest summer for at least 500 years: Swiss researchers Tue Sep 23, 2:46 PM ET GENEVA (AFP) - Europe this year experienced its hottest summer for at least 500 years, providing further evidence of man-made global warming (news - web sites), Swiss university researchers said. During the crushing heat wave between June and August this year, which triggered several thousand more deaths than usual, average temperatures eclipsed the previous record set in 1757, according to a study by the University of Bern's geography department. The average temperature in Europe was 19.5 degrees Celsius (67 degrees Fahrenheit), two degrees higher than the average summer temperatures recorded on the continent between 1901 and 1995. Central Europe and the Alps region were the worst affected by the heat wave, with temperatures up to five degrees higher than average, the study said. "It is very likely that human activity and greenhouse gases have caused this rise in temperature," said Juerg Luterbacher, who directed the study. Researchers said they had pieced together a picture of Europe's weather before the 19th century using physics, chemistry and the study of the natural world -- such as trees, whose bark grows thicker with hot weather They also relied on the writings of monks, many of whom started keeping weather records up to 500 years ago -- and found no evidence pointing to a summer hotter than 2003. "Monks used to write accurately and regularly about the weather, with indications about grapes harvest or flower blossom," Luterbacher said. "Climate historians know how to interpret that data and that is how we estimate the temperature of the time," he added. The researchers found that the number of very hot summers had increased towards the end of the 18th century and the early 19th century. The overall rise in summer temperatures in Europe has picked up over the last 26 years, with an average rise of 2.8 degrees Celsius between 1998 and 2003. The last decade was the hottest of all, the study said. In 1757, which set the previous European record, Scandinavia, eastern Europe and Russia experienced a record heat wave, the study added. The study spanned an area reaching from the Arctic Circle to Crete, and from Iceland to the Ural mountains. http://story.news.yahoo.com/news?tmpl=story2&u=/afp/20030923/sc_afp/climate_europe_weather_030923184658&e=3
Swiss glaciers shrink at record rate (Moderator)	posted 9/24/03 3:52 PM     Swiss glaciers shrink at record rate Ice line is also higher up mountains than normal Swiss glaciers are shrinking at three to four times their traditional rate. By Richard Waddington SION, Switzerland, Aug. 26 — Grayed by the heat and riven with deep cracks, Switzerland’s mighty Alpine glaciers are shrinking at a record rate in this summer’s sizzling sun. Scientists may disagree over some of the causes of the heat wave that sent temperatures soaring in Europe and about how much people are contributing to global warming, but the effects high in the Alpine valleys are visible. ‘It looks like our prediction was a little bit optimistic. It is going faster than we thought.’ — WILFRIED HAEBERLI University of Zurich geography professor THE ALPINE glaciers, source of some of Europe’s biggest rivers, have been in retreat for more than a century, but the loss of ice has speeded this year as temperatures have soared. “The rate of ice melt is some three or four times the usual amount,” said Charly Wuilloud, head of the department of natural dangers at the Valais state forestry department. Some 9,000 feet above the Rhone valley in southern Switzerland, at the junction of the Ferpecles and Mount Mine glaciers, the temperature is an unusually warm 59-68 degrees Fahrenheit. Sporting sunglasses and a short-sleeved shirt more typical of beach ware, Wuilloud pointed to the rush of melt water streaming from the ice wall of the Ferpecles glacier. The so-called equilibrium line, the point at which any fresh snow or rain falling will turn to ice and not melt or run off, is some 1,000 to 1,300 feet higher up the mountain this year than usual this summer, he added. At one time, the four-mile-long Ferpecles and Mount Mine joined to form a forked tongue of ice stretching down into the valley. Lines gouged into the mountain side high above the valley floor show the height to which the ice once reached. FASTER SHRINKING Scientists say Europe’s glaciers have been shrinking since the 1850s, initially as a result of a natural warming of the Earth following a 250 year cold snap. But the process has picked up pace over recent decades —particularly since the 1970s — under the impact of global warming fueled, many scientists believe, by high emissions of greenhouse gases. According to the United Nations’ International Panel for Climate Change, the average temperature of the earth rose 0.5 Celsius during the 20th century and could rise several times that rate over the next 100 years. Back in the 1990s, even before this year’s blistering summer, geologists at the Zurich-based World Glacier Monitoring Service forecast that the glaciers would shrink to just 10 percent of their 1850 size by the end of the 21st century. By 1970, they had already declined to around half and were seen losing a further 50 percent by 2025, according to geography professor Wilfried Haeberli of the University of Zurich. The latest estimates are that 25-30 percent has already gone. “It looks like our prediction was a little bit optimistic. It is going faster than we thought,” he told Reuters. Solar input A third of the sun's energy is reflected back into space after hitting Earth's upper atmosphere, but two thirds gets through, driving Earth's weather engine. The atmosphere A delicate balance of gases gives Earth its livable temperature. Known as "greenhouse" gases because they trap heat inside the atmosphere, they send a portion of that heat back to Earth's surface. The gases include water vapor, carbon dioxide, methane and nitrous oxide. The oceans Covering two thirds of Earth, oceans are the key source of moisture in the air and they store heat efficiently, transporting it thousands of miles. The oceans and marine life also consume huge amounts of carbon dioxide. The water cycle Higher air temperatures can increase water evaporation and melting of ice. And while water vapor is the most potent greenhouse gas, clouds also affect evaporation, creating a cooling effect. Clouds They both cool Earth by reflecting solar energy and warm Earth by trapping heat being radiated up from the surface. Ice and snow The whiteness of ice and snow reflects heat out, cooling the planet. When ice melts into the sea, that drives heat from the ocean. Land surfaces Mountain ranges can block clouds, creating ‘dry’ shadows downwind. Sloping land allows more water runoff, leaving the land and air drier. A tropical forest will soak up carbon dioxide, but once cleared for cattle ranching, the same land becomes a source of methane, a greenhouse gas. Human influences Humans might be magnifying warming by adding to the greenhouse gases naturally present in the atmosphere. Fuel use is the chief cause of rising carbon dioxide levels. On the other hand, humans create temporary, localized cooling effects through the use of aerosols, such as smoke and sulfates from industry, which reflect sunlight away from Earth. Glaciers have long been seen as one of the most sensitive detectors of climate change, with the impact showing up first in the thickness of the ice rather than its length, which can take years to respond. This year a number of factors have combined to intensify the rate of melt, including a freak weather event last November when a cloud of dust was blown north from the Sahara desert. As glacier surface ice melted with the coming of spring, the dust was exposed again, helping give the ice a grayish appearance that reduced reflection and increased the amount of sunlight absorbed — hence the melt. Although studies for this year are not yet finished, Haeberli said that the Alpine glaciers could have slimmed down some two yards or more — an exceptional loss of thickness. This would be 10 times the average annual melt over the length of the 20th century and some four times that of the two decades between 1980-2000. “This looks like a record year,” he said. “There is no doubt that it has been exceptional.” RISK TO RIVERS For those living in glacial valleys, the thinning of the glaciers when combined with heavy rain brings the danger of flash floods like the one that killed 13 people in the Gondo valley of Switzerland in 2000. Melt water can form lakes either on the surface of the glacier or below it that can suddenly be released with devastating consequences. Wuilloud said that the Valais authorities were already warning people not to camp near glacier-fed streams or other areas vulnerable to flooding. Over the long term, the shrinkage in the size of the glaciers could have a dramatic impact on water supply. In summer some 50 percent of the water carried by the Rhone from its source in the Alps through Lake Geneva to the Mediterranean comes from ice melt. “Glaciers hold water back in winter and let it go in summer,” Haeberli said. “If they go, so will the water.” © 2003 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content is expressly prohibited without the prior written consent of Reuters. http://stacks.msnbc.com/news/954944.asp?0bl=-0&cp1=1#BODY
Survey: Sierra Nevada Glaciers Shrinking - Shasta's Growing (Moderator)	posted 10/13/03 9:28 AM     Science - AP Survey: Sierra Nevada Glaciers Shrinking Sun Oct 12,11:54 PM ET LOS ANGELES - A new survey of Sierra Nevada glaciers shows ice slabs on many of the state's highest peaks are shrinking. A survey of seven Sierra Nevada glaciers, which were re-photographed over the summer, were all smaller than they were a century ago, said Hassan Basagic, a graduate student at Portland State University who initiated the survey. For example, Darwin Glacier near Bishop was an estimated 50 to 100 feet thinner than in historical photos from the early 1900s. "There's been lots of melt," said Nathan L. Stephenson, a research ecologist with the U.S. Geological Survey based at Sequoia National Park. Contrary to expectations, all seven of Mt. Shasta's glaciers have grown in recent decades, including Whitney, the largest in the state. Three of the mountain's glaciers have doubled in size since 1950, said Slawek Tulaczyk, a glaciologist who began the Mt. Shasta Glacial Survey in 2002. "We totally expected them to have shrunk, and they've grown dramatically," he said. Geography and weather may explain the different findings. "The climate of these two places is different," Tulaczyk said. Mt. Shasta, which he calls "a lonely mountain," captures moving weather patterns. The Sierra Nevada, on the other hand, "makes its own weather." Most ice worldwide has retreated in the past 100 years as the planet has rebounded from a cooling period called the "Little Ice Age" that ended around 1850. Glacier experts also suspect that ice caps may be dwindling faster as the planet warms in response to the human production of greenhouse gases, such as carbon dioxide. "I would never point the finger and say this is all human-induced warming," Stephenson said. "But maybe we are speeding it up now." http://story.news.yahoo.com/news?tmpl=story&cid=624&e=1&u=/ap/20031013/ap_on_sc/glacier_study
Arctic ice cap melting at worrisome rate: NASA	posted 10/24/03 7:00 AM     Friday October 24, 01:22 AM Arctic ice cap melting at worrisome rate: NASA WASHINGTON (AFP) - The polar ice cap is melting at an alarming rate due to global warming, NASA scientists said, with satellite images showing the ice cap continuing to shrink. "It is happening now. We cannot afford to wait a long period of time for technological solutions," said David Rind of NASA's Goddard Institute for Space Studies in New York. "Change is in the air -- literally." The part of the Arctic Ocean that remains frozen all year round shrank at a rate of 10 percent per decade since 1980, NASA researcher Josefino Comiso said. That cap reached record lows in 2002 and 2003, he added. Researchers at the National Aeronautics and Space Administration are worried because global warming speeds up as the ice cap melts, forming a vicious cycle. "Snow and sea-ice are highly reflective because they are white," Comiso said. "Most of the sun's energy is simply reflected back to space. With retraction of the ice cover, that means that less of surface is covered by this highly reflective snow and sea ice, and so more energy has been absorbed and the climate warms." US and Canadian scientists reported in September that the largest ice shelf in the Arctic off Canada's coast has broken up due to climate change and could endanger shipping and drilling platforms in the Beaufort Sea. The Ward Hunt Ice Shelf had been in place on the north coast of Ellesmere Island in Canada's Nunavut territory for at least 3,000 years. http://uk.news.yahoo.com/031024/323/ec0fr.html
Plankton may protect Earth from icy fate	posted 11/3/03 2:08 AM     New Scientist|AFP Friday October 31, 01:01 PM Plankton may protect Earth from icy fate By Duncan Graham-Rowe The evolution of tiny, shelled sea creatures ended a 200 million year era of extreme ice ages and has protected the Earth from any repeat ever since, suggest the results of a new modelling study. During the frozen period, known as "snowball Earth" the polar ice caps extended far down into low latitudes, covering much of the planet. The emergence of the plankton, which incorporate carbon dioxide into calcium carbonate shells, created a new stability in the planet's carbon cycle, argue Andy Ridgwell, at the University of Riverside, California, and his colleagues. The minute organisms did this by providing for the first time a way to dump calcium carbonate into the deep waters below the open oceans. Chemical processes in the sea that dissolve calcium carbonate deposits alter the acidity of the water. This helps regulate the amount of atmospheric carbon dioxide that can dissolve in seawater. And this in turn helps the planet to regulate its temperature. Drift down Today, plankton with carbonate shells, like coccolithophoridae and foraminifera, live throughout large parts of the ocean. When they die, most drift down and settle deep on the ocean floor, where their shells dissolve. But during the Neoproterozoic period, from 1000 to 540 million years ago, such organisms had not yet evolved. As a result, the dissolution of most calcium carbonate deposits occurred in shallow coastal regions. Ridgwell and his colleagues think that while these shallow water processes served well as a global thermostat for most of the time, they could be overwhelmed relatively easily. This was particularly the case when sea level dropped, reducing the area of the shallow oceans. Feedback effect A snowball Earth glaciation would start with a slight cooling of the climate, causing the ice caps to grow. This would have led to sea level dropping, enhancing the cooling. The thermostat would stop working, Ridgwell says. The ice caps themselves would also cause a feedback effect by reflecting more of the Sun's warmth than ocean. This, and the broken thermostat, would plunge the Earth into a severe ice age, which would only be broken by the eventual build up of carbon dioxide emitted from volcanoes. But the arrival of the plankton, which could carry carbonate to the deep oceans, provided a new buffer. Unlike the shallow oceans, the deep oceans never become saturated with carbonate, making them a much more reliable and sensitive thermostat. Ridgwell told New Scientist this may well be why the Earth has not suffered any catastrophic ice ages since the plankton evolved. "It's an intriguing idea," says David Archer, in the Department of Geophysical Sciences at the University of Chicago. "But it will certainly be contentious." It has been know for some time that plankton play a role in burying organic carbon, he says. "What's new here is the idea that having calcium carbonate deposition in the deep sea makes the system more stable than it would be with only shallow water deposition." Journal reference: Science (vol 302, p 859) http://uk.news.yahoo.com/031031/12/ecowu.html
Climate change may be veering out of control before we understand the consequences	posted 11/3/03 2:11 AM     Alarm over acidifying oceans 18:00 25 September 03 Climate change may be veering out of control before we understand the consequences, say scientists studying the world's oceans. If carbon dioxide emissions keep rising, surface waters could become more acidic than they have been for 300 million years - except perhaps during global catastrophes. And this warning follows a report that the biological productivity of the oceans has fallen by six per cent since the 1980s. "We are changing the chemistry of the ocean and we don't know what it's going to do," says Ken Caldeira, a climate specialist at Lawrence Livermore National Laboratory in California. As the amount of CO2 in the atmosphere rises, more of the gas reacts with seawater to produce bicarbonate and hydrogen ions, increasing the acidity of the surface layer of water. Ocean pH was 8.3 after the last ice age and 8.2 before CO2 emissions took off in the industrial era. It is now 8.1. To work out what might happen in the future, Caldeira and his colleague Michael Wickett assumed the "business as usual" scenario, in which CO2 emissions rise with population and economic growth throughout this century, then decline as fossil fuels are exhausted. In this scenario, atmospheric CO2 levels peak around the year 2300 at 1900 parts per million (ppm), five times as high as today. The researchers calculate that because the ocean will soak up some of this CO2, its surface pH will drop to 7.4 by 2300 and stay that low for hundreds of years (Nature, vol 425, p 365). Vulnerable creatures Atmospheric CO2 has risen well above 2000 ppm several times in the past 300 million years. Caldeira says this never pushed ocean pH below 7.5 because carbonate rocks on the seafloor act as a natural buffer, limiting seawater's acidity. But that process takes 10,000 years or so - enough time to neutralise acid deposited by geological processes, but not to deal with the more rapid changes caused by human activity or natural catastrophes such as asteroid impacts. It is not clear what such a dramatic change in acidity would do to ocean life. But acidity tends to dissolve carbonate, so the most vulnerable creatures will be those with calcium carbonate shells or exoskeletons, such as corals and some algae. Experiments with double the present CO2 level in the giant, self-contained greenhouse Biosphere 2 showed that the rate of calcium carbonate formation in such animals fell by 40 per cent. Meanwhile, satellite measurements of chlorophyll levels in the open ocean show that primary productivity - the amount of new biomass being produced from carbon dioxide by photosynthesis - has dropped sharply in the past couple of decades (Geophysical Research Letters, DOI: 10.1029/ 2003GL016889). Dust clouds A team led by Watson Gregg of the NASA Goddard Space Flight Center in Greenbelt, Maryland, compared data from two instruments: the Coastal Zone Color Scanner, which worked from 1979 to 1986, and the Sea-viewing Wide Field of View Sensor (SeaWiFS), which has been running since 1997. Across the globe, the researchers found ocean productivity has dropped by an average of six per cent since the 1980s. There were regional variations, however, and Gregg says there is probably a range of causes. In northern waters, sea surface temperatures have risen, reducing mixing between layers and decreasing the supply of nutrients to the surface. This may have cut productivity. Meanwhile, extra nutrients deposited from dust clouds may have contributed to higher productivity in equatorial waters. The drop could just be part of a natural cycle, but Gregg says we know so little about the factors controlling ocean productivity that it is impossible to be sure. He and others warn that by failing to control CO2 levels, we are making a huge leap in the dark. "We are taking the reins of the geochemical cycles of the Earth," says David Archer, an expert in global carbon cycles from the University of Chicago. "It's really frightening." Jeff Hecht http://www.newscientist.com/news/news.jsp?id=ns99994196
Volcanoes help unleash El Nino disaster: study	posted 11/20/03 3:45 AM     Wednesday November 19, 07:05 PM Volcanoes help unleash El Nino disaster: study PARIS (AFP) - Volcanoes are a prime cause for El Nino, the climate phenomenon that can catastrophically disrupt weather patterns across the Pacific and beyond, a study says. A major eruption doubles the chance that an El Nino will be unleashed in the following winter, according to the research, which is published on Thursday in the British scientific journal Nature. The research is the first to supply statistical flesh to the theory that volcanic fallout may affect the world's climate system, spewing out billions of tonnes of fine ash that lingers in the upper atmosphere, reflecting back solar heat. Climate experts led by Brad Adams of the University of Virginia looked at so-called geological indicators -- dust preserved in polar ice cores as well as tree rings and coral growth that reflect sudden changes in the climate -- and compared this with the dates of major known eruptions from 1649 onwards. They found a "significant, multiyear El Nino-like response" that kicked in just after big volcanic activity in the tropics. "The results imply roughly a doubling of the probability of an el Nino event occurring in the winter following a volcanic eruption," they write El Ninos occur in cycles that vary from three to 11 years, when the sea surface temperature in the western tropical Pacific Ocean is warmer than usual. The prevailing east-west trade winds die, causing a huge buildup of warm water in the western part of the ocean. This has effects on climate that can reverberate around the southern hemisphere, inflicting snowfalls and landslides in South America, drought in southern Africa, a weak hurricane season in the Atlantic and forest fires in Indonesia. The shift in weather is so abrupt that crops and fish migrations are hit, having a dramatic effect on human life. Adams' team believes that the fine shroud of volcanic ash kick-starts the process. A thin layer of "aerosolised" particles hangs in the stroposphere, causing an overall cooling of the planet's atmosphere of a few tenths of a degree Celsius (about half a degree Fahrenheit). But the effect regionally is different. There is a complex interaction between atmospheric temperatures and vast, circulating masses of water. Athough the rest of the world cools, there is a slight warming in the tropical zone of the Pacific, fuelled in part by a convection of warm water from elsewhere. That small rise is is enough to trigger an El Nino, which is highly susceptible to small changes in sea surface temperatures. According to the study, the El Nino usually lasts for the first three years after a big tropical volcanic eruption, and then goes into reverse, with the so-called El Nina phenomenon, for the three years after that. But the researchers add a big caveat: eruptions themselves are not the only factor. Man-made global warming -- the spewing out of greenhouse gases by the burning of fossil fuels -- is also likely to play a role. "Volcanic eruptions, such as that of Mount Pinatubo (in the Philippines) in 1991 may have a larger effect on Earth's climate than previously thought," says Shanaka de Silva of the Department of Space Studies at the University of North Dakota, in a commentary. "If they influence the (El Nino) cycle as proposed, then explosive volcanism is a vital catalyst in global climatic interconnections, and a major player in Earth's climate system." http://uk.news.yahoo.com/031119/323/eeen7.html
Ram	posted 4/19/04 2:42 AM     Posted on Wed, Dec. 17, 2003 U.N. Says 2003 3rd Hottest Year on Record JONATHAN FOWLER Associated Press GENEVA - The year 2003, marked by a sweltering summer and drought across large swaths of the planet, was the third hottest in nearly 150 years, the United Nations weather agency said Tuesday. The World Meteorological Organization estimated the average surface temperature for the year to be 0.81 degrees Fahrenheit higher than the normal 57 degrees. The agency said that warmer weather could not be attributed to any one cause but was part of a trend that global warming was likely to prolong. The agency, which collects data from forecasters worldwide, said the three hottest years since accurate records began to be kept in 1861 have all been in the past six years. The hottest was 1998, when the average temperature was up 0.99 degrees. "The rhythm of temperature increases is accelerating," said WMO deputy secretary-general Michel Jarraud. This summer, much of Europe was struck by a prolonged heat wave, with temperatures exceeding 104 degrees. The hot weather was blamed for the deaths of thousands, most in France, and devastating forest fires in several countries. It also accelerated the melting of Alpine glaciers, the WMO said. India and Pakistan also were hit by a deadly heat wave in May and June, when 1,500 people died as temperatures soared above 122 degrees Fahrenheit. The western United States continued to suffer from drought, and wildfires in California burned nearly 75,000 acres of land in October. In the southern hemisphere springtime, Australia logged a record September temperature of over 109 degrees. Over the 2002-03 winter, North America received its 10th lowest recorded snowfall, although the northeastern United States was battered a record snowstorm in February, the agency said. Other parts of the world also faced extreme winter weather. January temperatures in northeastern Russia dropped to -49 degrees, while Mongolia also was gripped by an exceptionally harsh winter for the third year running, devastating livestock. As winter hit the southern hemisphere, 200 people were killed in Peru when temperatures fell to -4 degrees Fahrenheit. "You cannot attribute this to any single cause," Jarraud said. "It's about the very complex interaction between all the elements that make up the very complex machine that is the Earth." In the Atlantic Ocean, 16 separate storms developed this year, well above the 1948-96 average of 9.8. Hurricane Isabel, which battered North Carolina, was one of the strongest on record. Hurricane Fabian was the most destructive to hit Bermuda in 75 years. "By definition, exceptional events are exceptional, so they don't occur very often," said Jarraud. "But global warming is likely to lead to more frequent extraordinary events and greater intensity of these events." Separately Tuesday, Swiss Reinsurance Ltd., which backs insurance companies against major claims and analyzes the effect of disasters, said 20,000 people were killed by natural catastrophes in 2003. Swiss Re said its preliminary findings showed that disasters caused total losses of $65 billion. Insurers paid out $15 billion, it said. -AP http://www.fortwayne.com/mld/fortwayne/7508048.htm Mars was once 'soaked' with water
Ram	posted 4/19/04 2:45 AM     Friday April 16, 12:30 PM Scientists stirred to ridicule ice age claims By Fred Pearce Climate scientists have been stirred to ridicule claims in an upcoming Hollywood blockbuster that global warming could trigger a new ice age, a scenario also put forward in a controversial report to the US military. The $125-million epic, The Day After Tomorrow , opens worldwide in May. It will show Manhattan frozen solid after the warm ocean current known as the Gulf Stream shuts down. The movie's release will come soon after a report to the US Department of Defense (DoD) in February predicting that such a shutdown could put the northern hemisphere into a deep freeze and trigger global famine within 15 years. But in the journal Science on Thursday, Andrew Weaver of the University of Victoria in British Columbia, Canada, surveys the current research and concludes "it is safe to say that global warming will not lead to the onset of a new ice age". Salty water The DoD's doomsday scenario, which is very similar to that in the film, was drawn up by Peter Schwartz and Doug Randall of the San Francisco-based Global Business Network. Neither is a climate scientist. The scenario suggests that as global warming melts Arctic ice packs, the North Atlantic will become less salty. This would shut down a global ocean circulation system that is driven by dense, salty water falling to the bottom of the north Atlantic and that ultimately produces the Gulf Stream. This much is respectable scientific theory, and some researchers believe it could happen for real in 100 years or so. But the film-makers and DoD authors go further. They say it could happen very soon. And that if it did, the northern hemisphere would cool so much that that ice sheets would start to grow, creating a catastrophic new ice age. This is too much even for sympathetic climatologists. Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research in Germany, whose own models say the Gulf Stream could shut down within a century, told New Scientist : "The DoD scenario is extreme and highly unlikely." Achilles heel And Wallace Broecker of Columbia University, New York, US, who has warned for two decades that the Atlantic circulation is "the Achilles heel of our climate system", seriously questions both the speed and severity of the changes proposed. In a letter to Science , he accuses the DoD authors of making exaggerated claims that "only intensify the existing polarisation over global warming". He adds: "What is needed is not more words but rather a means to shut down CO 2 emissions." Such action could avert any Gulf Stream shutdown in the next 100 years. Schwartz defends his scenario, saying that while it is "not the most likely scenario, it is plausible, and would challenge US national security in ways that should be considered immediately". Weaver notes that the movie's budget "would fund my entire research group for my entire life, 10 times over". That might even allow him to discover which scenarios are most plausible. But there are no sour grapes. "I will be one of the first to see the movie.," he says. "It'll be the Towering Inferno of climate - extremely entertaining." It will not confuse the public, he thinks, but it will not help them understand climate science either. http://uk.news.yahoo.com/040416/12/er73s.html Scientists stirred to ridicule ice age claims
Ram	posted 5/7/04 2:58 AM     Science - Reuters New Group Battling to Beat Climate Change Thu May 6, 9:50 AM ET By Jeremy Lovell WEYBRIDGE, England (Reuters) - Environmental activist Steve Howard hopes to work himself out of a job within a decade. As head of the newly formed Climate Group, Howard's mission is to divert the planet from the path of seemingly inevitable self-destruction due to global warming and climate change. "I would like to see in 10 years' time that things have moved on so much that we are redundant," he told Reuters in an interview at the group's British headquarters in Weybridge, some 20 miles southwest of London. Experts have warned that climate change is the biggest single threat mankind has ever faced, with predictions of rapidly rising temperatures producing rising sea levels and devastating floods and droughts. "If there was a huge asteroid heading for Earth on a path that looked like being a direct hit we would all mobilize to do something to divert it. Climate change is that asteroid, and the way we are going now it will be a direct hit," Howard said. The Climate Group, publicly launched last week in London with the blessing of the British government and funded by the U.S.-based Rockefeller Brothers Fund, aims to persuade governments, companies and even individuals to slash greenhouse gas emissions. "There is no disputing the fact that climate change is happening now. We have a window of opportunity. We have to use it," said Howard. Warning signs are already easy to spot. The ski industry, for example, is already starting to suffer from the warmer climate, as is the wine industry, and extreme events such as last year's European heatwave in which some 20,000 people died are likely to become commonplace, he predicted. "This is the tip of the melting iceberg on climate change. Many people have yet to see what is coming toward them. This is the wake-up call," Howard said. Forget the Kyoto treaty on cutting carbon dioxide emissions -- already rejected by chief polluter the United States and expected to be treated likewise by Russia -- the Climate Group's aim is to go far beyond those modest goals. "Kyoto is an important first step. But we need a 50 to 60 percent carbon emission reduction and we need it a lot faster," Howard said. "We are moving to a low carbon world. There is no doubting that. Things will have to change from transport systems to building design," he added. "Some are already doing it and saving money in the process. Everyone will have to follow." The group, which will hold a major meeting in Toronto at the weekend, has already attracted some backing from companies including global banking group HSBC, British oil major BP and Danish-based home furnishing group Jysk. But Howard insists that the bulk of funding will always come from philanthropic organizations and insists he will never be in thrall to big business. "We will define what is best practice and give real leadership. This will be a very transparent process. There is real scope to make a major difference," he said. "We will have an open-door policy so that city, state and corporate can approach us from around the world. But our focus will be on countries with big emissions like the EU, U.S, Canada, Russia, China, India and Japan," he added. http://story.news.yahoo.com/news?tmpl=story&cid=585&e=3&u=/nm/20040506/sc_nm/environment_climate_dc New
Early farmers warmed Earth's climate	posted 6/8/04 6:30 AM     Early farmers warmed Earth's climate 12:13 11 December 03 Our tampering with Earth's climate did not begin just a few decades or centuries ago, but 8000 years before, with the birth of agriculture. This controversial theory drastically widens the debate about the timing and extent of humans' impact on the Earth. William Ruddiman, a climate scientist at the University of Virginia in Charlottesville, started to suspect that ancient human activities have affected the climate when he noticed a telltale discrepancy in levels of greenhouse gases revealed by ice cores. During the previous three periods between ice ages, levels of carbon dioxide and methane in the air fell in lockstep with decreases in summer sunshine caused by cyclical changes in Earth's orbit. But after the most recent ice age, which peaked about 12,000 years ago, the two gases broke the pattern (see graphic). Early warming Levels of atmospheric carbon dioxide began to increase 8000 years ago, followed by methane 5000 years ago, even though summer sunshine has been decreasing. "Both gases followed the expected trend for a while but then went up instead of down," says Ruddiman. "It didn't quite fit." Rice paddies After ruling out possible natural causes for the greenhouse gas increases, Ruddiman now thinks that early farmers clearing forests in Europe, India and China account for the surge of carbon dioxide, while rice paddies and burgeoning herds of livestock produced the extra methane. He estimates that over time this activity laced the atmosphere with about 40 parts per million of carbon dioxide and 250 parts per billion of methane, enough to produce nearly 0.8 °C of warming before 1700, around the dawn of industrialisation. If he is right, that just about equals the warming humans are thought to have caused since then. Intriguingly, Ruddiman thinks the anomalous cooling of the "little ice age" that gripped the world for several centuries from around 1300 was caused by a specific setback to agriculture ­ plague. He notes that pandemics of bubonic plague depopulated Eurasia during those same centuries. Fields and villages were abandoned and reclaimed by fast-growing forests that sucked carbon dioxide out of the atmosphere, resulting in the cooler temperatures felt worldwide. This completely reverses the widely held idea that it was the little ice age that caused the famine, depopulation and disease. Glacial creep Another surprising implication of Ruddiman's theory is that the warming before 1700 ­ 0.8 °C globally, but nearly 2 °C in far northern latitudes ­ may have saved Canada from renewed glaciation. If levels of greenhouse gases had continued to fall after the most recent ice age, as they did after the three preceding ice ages, glaciers would once again have spread across north-eastern Canada about 4000 years ago. Geochemist Jeff Severinghaus at the Scripps Institution of Oceanography in San Diego, California, is wary. "I think it's very interesting," he says, "but very speculative. I doubt that ancient humans could have done that." Others are more positive. "It's provocative," says Pennsylvania State University glaciologist Richard Alley, but "absolutely worth following up". Robert Adler http://www.newscientist.com/news/news.jsp?id=ns99994464
Record ice core gives fair forecast	posted 6/11/04 3:48 PM     Record ice core gives fair forecast 18:00 09 June 04 NewScientist.com news service As long as humans do not mess it up, the Earth's climate is set at fair for the next 15,000 years. That is according to information extracted from the oldest ice core ever drilled. The Antarctic core is the first to reach as far back as a warm period with characteristics similar to our own interglacial. So it should help make more accurate predictions about when to expect the next deep freeze. The ice core, drilled from a feature in central Antarctica called Dome C, is around 3 kilometres long and 10 centimetres wide. Changes in the relative proportions of hydrogen isotopes in the ice layers allow scientists to compile a complete record of Antarctic temperatures going back 740,000 years. The core shows the waxing and waning of eight ice ages. Most critically for making predictions about our climate, it is the first core to record a period known as Termination V, around 430,000 years ago. Warming pattern At this point, the world moved from a glacial period into a long, warm interglacial, similar to this era. The previous longest ice-core record, drilled by the Soviet Union at Vostok in Antarctica between 1980 and 1988, went back only 420,000 years. "All interglacials are slightly different, but we believe Termination V is the most similar to our own," says chief author of the new study, Eric Wolff, at the British Antarctic Survey in Cambridge, UK. It mirrors the pattern of solar warming between seasons and at different latitudes that are caused by fluctuations in the Earth's orbit known as the Milankovitch cycles. It shows that the Termination V interglacial was unusually long, lasting 28,000 years. The current interglacial is now 12,000 years old, and some scientists feared that we might be heading for an ice age soon since at least one post-Termination V interglacial lasted just 10,000 years. But the new findings suggest that even without the human hand in global warming, a new ice age would be unlikely for perhaps another 15,000 years, Wolff says. Ice blanket The core also sheds light on how ice ages have changed over the past million years. Since Termination V, ice ages have been very intense, with periods of cold weather that blanketed much of the northern hemisphere in ice for 80,000 years punctuated by short interglacials lasting typically 20,000 years. But the new core shows that, prior to Termination V, the cold and warm periods of the glacial cycle each lasted around 50,000 years but were much less intense. "Marine deposits suggested some of this, but it stands out much more clearly in the ice record," Wolff says. Meanwhile, European and US scientists are discussing plans to survey for a site in Antarctica that will extend the record still further. "We want to go back at least 1.2 million years next time," Wolff says. "But we have to find somewhere that we can do it." Journal reference: Nature (vol 429, p 623) Fred Pearce http://www.newscientist.com/news/news.jsp?id=ns99995094
Amazon Fires Change Weather, Speed Deforestation	posted 7/28/04 12:35 AM     Science - Reuters Amazon Fires Change Weather, Speed Deforestation Tue Jul 27, 5:31 PM ET By Axel Bugge BRASILIA, Brazil (Reuters) - Burning of the Amazon jungle is changing weather patterns by raising temperatures and reducing rainfall, accelerating the rate at which the forest is disappearing and turning into grassland, scientists said on Tuesday. Wide-scale burning by loggers and farmers of the Amazon has risen sharply over the past two decades, changing the region's cloud cover and reducing the amount of rain in some deforested areas that are turning into grassland or savanna. "All the models indicate the same thing, 'savannization,"' Pedro Leite Silva Dias of the University of Sao Paulo said at a conference on research on Amazon deforestation. Silva Dias said the worst-case scenario for the Amazon, a continuous tropical forest larger than the continental United States, is that at current burning and deforestation rates, 60 percent of the jungle will turn into savanna in the next 50 to 100 years. The most likely outlook is that 20 to 30 percent will turn into savanna, according to forecasting models. Destruction of the Amazon, home to up to 30 percent of the globe's animal and plant species, reached its second-highest level last year. An area of 5.9 million acres, bigger than the state of New Jersey, was destroyed as loggers and farmers hacked and burned the forest in 2003. About 85 percent of the Amazon is still standing. The Amazon experts are presenting the latest findings of the Large Scale Biosphere-Atmosphere Experiment in Amazonia, the world's largest experiment on jungle deforestation. The experiment, which includes U.S. space agency NASA (news - web sites), has found increasing evidence that the Amazon is slowly getting drier due to burning, with unpredictable consequences for its survival and weather patterns. The experiment has monitored the Amazon since 1998, using research towers and a unique satellite image system. As the climate becomes drier and reduces the colossal amount of water vapor over the Amazon, the effects will spread internationally, the experts said. "Clouds over the Amazon are not in their normal state. The repercussions of this are going to be felt far away," said Meinrat Andreae of Germany's Max Planck Institute of Chemistry. "This leads to significant changes of global (cloud) circulation." Experts have found that burning of the Amazon, accounts for 75 percent of Brazil's greenhouse gas emissions, making Brazil one of the world's top 10 polluters. The scientists said the Amazon's climate is already getting hotter due to global warming. Burning in the area itself is accelerating that process. http://story.news.yahoo.com/news?tmpl=story&cid=585&e=1&u=/nm/20040727/sc_nm/environment_amazon_dc
Natural Sunblock: Sun Dims in Strange Ways	posted 8/3/04 12:23 AM     Science - Space.com Natural Sunblock: Sun Dims in Strange Ways Mon Aug 2, 5:40 PM ET By Robert Roy Britt Senior Science Writer SPACE.com When Venus crossed the Sun June 8, showing up as a clear black dot to the delight of millions of skywatchers around the world, astronomers noted something less obvious: The amount of sunlight reaching Earth dipped by 0.1 percent for a few hours. The result was not a surprise, but since Venus hadn't transited the Sun in more than a century, the effect had never been measured. The drop in sunlight was similar to what happens when a large sunspot crosses the solar surface. But these forms of natural sunblock don't behave as you might expect, as witnessed by folks who froze their tails off a few hundred years ago across much of the Northern Hemisphere. Two types of transits Sunspots are cool, dimmer regions of the solar surface, packed with pent-up magnetic energy that sometimes unleash storms of X-rays and superheated gas. When they transit the face of the Sun, they are often visible without magnification to skywatchers using safe viewing techniques (looking directly at the Sun can cause permanent eye damage). The planets Venus and Mercury, both orbiting inside Earth's path, also transit the Sun. Sunlight reaching Earth is monitored by NASA (news - web sites)'s Solar Radiation and Climate Experiment (SORCE) satellite. The Venus transit proved to be a good test of instrument sensitivity. "Because of its distance from Earth, Venus appeared to be about the size of a sunspot" on June 8, said Gary Rottman, SORCE Principal Investigator and a scientist at the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder. Rottman and colleagues saw greater reductions in the Sun's energy coming Earthward during a stretch of intense solar activity last October, when several huge sunspots generated a record-breaking string of solar flares. At one point, sunlight dimmed 0.3 percent for about four days, due mostly to three large sunspot groups. "This is an unprecedented large decrease in the amount of sunlight," Rottman said, and it is comparable to the decrease that scientists estimate occurred from roughly 1645 to 1715. During a broader period, from the 1400s to the 1700s, Europe and North America were plunged into what came to be called the Little Ice Age. Dearth of sunspots Scientists could not measure solar radiation back then. But sunspots were recorded by several astronomers, and Rottman and others believe there is a correlation between the climate of the time and the lack of sunspots. "For a period of about 50 years, there were almost no sunspots," Rottman said in a telephone interview. "The total amount of radiation was, we assume, about three-tenths of 1 percent less" than in normal periods of solar activity. If you've been paying attention, that might sound backward. Rottman's team measured a decrease in sunlight when Venus transited the Sun, and similar decreases are recorded when sunspots are present. So why would there have been less radiation in the late 1600s when there were very few sunspots? Rottman explains: Sunspots indicate greater solar activity in general. While they do dampen sunlight while on the face of the Sun, they are surrounded by intensely bright regions called "faculae" or "plage." When sunspots are on the limb of the Sun -- just rotating onto or off of the face -- the plage are prominent from our vantagepoint, creating a significant increase in radiation that far outweighs the dip of radiation caused by the rest of the sunspot's transit. Seen on a graph, total visible and infrared radiation increases just before a sunspot appears, dips slightly for several days as it crosses the surface, then increases again as it disappears. A lack of sunspots indicates inactivity in the Sun, and less radiation overall. Still a mystery The reduced solar activity of the 1600s and 1700s is called the Maunder minimum, after the solar astronomer Edward Walter Maunder, who during the 1800s investigated the historical sunspot records. Nobody knows for sure why it occurred or whether it will happen again anytime soon. In fact, the whole concept remains controversial, because it's not clear how well astronomers were counting sunspots during the Maunder minimum. And the exact tie to climate is not understood. Most tend to agree, however, that there was a distinct lack of solar activity. "Something very different was happening during the 17th Century, and it produced a much more permanent change in the Sun's energy output at that time," Rottman said. http://story.news.yahoo.com/news?tmpl=story&cid=96&e=1&u=/space/20040802/sc_space/http://story.news.yahoo.com/news?tmpl=story&cid=96&e=1&u=/space/20040802/sc_space/naturalsunblocksundimsinstrangeways
Ancient Rome's fish pens confirm sea-level fears	posted 8/16/04 3:38 PM     New Scientist | AFP Monday August 16, 01:30 PM Ancient Rome's fish pens confirm sea-level fears By Jeff Hecht Coastal fish pens built by the Romans have unexpectedly provided the most accurate record so far of changes in sea level over the past 2000 years. It appears that nearly all the rise in sea level since Roman times has happened in the past 100 years, and is most likely the result of human activity. Sea-level change is a measure of the relative movement between land and sea surfaces. Tide-gauge records show that the sea level has been rising 1 to 2 millimetres a year since widespread measurements began around 1900, but do not pinpoint when the trend started. Earlier sea levels can be estimated from geological data, but the accuracy is limited to about half a metre, which is not enough to precisely chart the history of sea-level rise. So Kurt Lambeck of the Australian National University in Canberra turned to fish pens on the Tyrrhenian coast of Italy for a more accurate record of ancient sea level. Ice age rebound The Romans dug these fish pens into bedrock, and the water line in these well-preserved structures shows that the sea level along the Italian coast 2000 years ago was 1.35 metres below today's levels. "They were used for only a very short time, so they make rather nice markers," says Lambeck. He then analysed how land elevations changed along the Italian coast due to both plate tectonics and the after-effects of the last ice age. In a paper to appear in the journal Earth and Planetary Science Letters , he concludes that geological processes pushed the land up by 1.22 metres over last two millennia, which means that the global sea level rose by 13 centimetres. That is only about 100 years' worth of rise at the present rate of around 1 to 2 millimetres per year, implying that nearly all of it has occurred since 1900. While there is no proof that human activity is to blame, "I can't think of a natural process that would have started in 1900," he says. The result "is a significant one", says Jonathan Gregory, who studies global changes in sea level at the University of Reading, UK. The finding supports the idea, based on the few tide-gauge records that extend back two centuries, that the rise in sea level did indeed accelerate about a century ago. While Gregory cautions that this does not prove that global warming is responsible, both he and Lambeck agree that the results fit the rise in ocean volume expected from global warming melting glaciers in the industrial age. http://uk.news.yahoo.com/040816/12/f0f95.html
Global Warming Thaws Arctic, Divides Governments	posted 9/4/04 9:35 AM     Science - Reuters Global Warming Thaws Arctic, Divides Governments Fri Sep 3,11:34 AM ET By Alister Doyle OSLO (Reuters) - Global warming (news - web sites) is set to accelerate in the Arctic and bring drastic change for people and wildlife in coming decades, according to a draft report that has opened cracks among nations in the region about how to slow the thaw. "(The) Arctic climate is warming rapidly now and much larger changes are projected," according to the conclusions of the international study, compiled by 600 experts and due for release at a conference in Iceland in November. Rising temperatures will disrupt life for people, bringing more storms and destabilizing everything from homes to oil pipelines. Melting glaciers could raise global sea levels and spoil habitats for creatures like polar bears, it says. The Arctic is warming faster than the rest of the world partly because sea water and dark ground, once exposed, trap far more heat than ice and snow which reflect the sun's rays. The report's draft summary, a copy of which was obtained by Reuters on Friday, says the rise in temperatures is being stoked by human emissions of greenhouse gases, mainly from burning fossil fuels in cars, factories and power plants. Arctic temperatures could surge by 4-7 Celsius (8-14 F) -- or roughly double the rate predicted by UN studies for the planet as a whole by 2100, it says. But nations in the Arctic region -- the United States, Russia, Canada and Nordic countries -- are sharply divided about how to act on the scientists' conclusions, with Washington opposed to any major initiatives, diplomatic sources say. U.S. OPPOSES CAPPING EMISSIONS Nordic countries see the study as alarming evidence that the world should act to cap emissions of greenhouse gases like carbon dioxide from fossil fuels. But President Bush (news - web sites) is an opponent of caps and pulled out of the UN's stalled Kyoto protocol in 2001, the main global plan for limiting emissions. He said Kyoto would be too costly and wrongly excluded developing nations. Ministers from Arctic nations are to meet in Iceland in November, after the report is issued, to agree recommendations. Among conclusions, the Arctic Climate Impact Assessment (ACIA) says the warming in the Arctic will "have worldwide implications." Run-off from melting glaciers and the Greenland icecap could raise global sea levels and disrupt ocean circulation, it says. And biodiversity elsewhere could be affected because some migratory species breed in the Arctic. The report also says "Arctic vegetation zones are projected to shift, bringing wide-ranging impacts" and that "Animal species' diversity, ranges and distributions will change, some dramatically." Meanwhile, it says, many coastal communities and facilities face increasing exposure to storms. And indigenous peoples would face major economic and cultural impacts, it says. Ultraviolet radiation -- known to cause skin cancer and immune system disorders in humans -- would also rise sharply. The report also concludes that "reduced sea ice is very likely to increase marine transport and access to resources." The thaw could open short-cut shipping routes between the Atlantic and Pacific Oceans. But on land, buildings, oil pipelines, industrial facilities, roads and airports could need substantial rebuilding if permafrost thaws, it says. http://story.news.yahoo.com/news?tmpl=story&cid=585&e=2&u=/nm/20040903/sc_nm/environment_arctic_dc
Antarctic glaciers slipping faster into the sea	posted 9/30/04 10:23 AM     Antarctic glaciers slipping faster into the sea 19:00 23 September 04 NewScientist.com news service Antarctic glaciers are thinning and slipping ever faster into the sea, according to several new studies. Warmer air and sea temperatures are blamed, and the changes are expected to cause an appreciable rise in sea levels. Glaciologist Robert Thomas, a NASA contractor in Wallops Island, Virginia, US, led a team that flew over West Antarctica in 2002 and measured the thickness of six glaciers flowing into the Amundsen Sea with radar. He found the glaciers were thinning at twice the rate they had in the 1990s, when a European satellite measured them. The glaciers are losing about 250 cubic kilometres of ice to the ocean each year - about 60% more ice than they accumulate from snowfall. That translates to a global sea level rise of 0.2 millimetres a year - equivalent to 10% of the current rising levels. The glaciers are also accelerating toward the sea. One, the Pine Island Glacier, has sped up by about 25% over the last 30 years. Warmer waters The changes are linked to the thinning and weakening of ice shelves that the tongue-shaped glaciers flow into before reaching the sea. These shelves are generally bounded by rock or anchored ice on all sides but the one facing the sea. So when warmer seawater erodes the bottom of these shelves, glaciers ramming into them can break them off more easily. "It's like pulling a cork out of a tilted bottle - the contents start to spill out," Thomas told New Scientist. The research suggests this can set off a chain reaction of thinning that can spread like a crack for more than 1000 kilometres inland. "If that deep channel goes far into the interior of the ice sheet, it's a weak link where instabilities can creep back to the heart of the ice sheet and help the ice sheet collapse," Thomas says. The root cause is more heat getting to the bottom of the ice shelves, says Thomas, who publishes his work in Science (DOI: 10.1126.1099650). "But whether it's the same ocean currents but warmer water, or the same temperature water but the currents have speeded up isn't clear," he adds. Global warming or some natural, unknown cycle may be responsible for the warmer water, he says. Shelf collapse Two other studies, published on Wednesday in Geophysical Research Letters (vol 31, L18401 and L18402), describe similar changes in glaciers on the Antarctic Peninsula. There, a 3250-square-kilometre ice shelf called Larsen B collapsed in March 2002 after being weakened by temperatures that rose about five times as fast as the global average over the previous five decades. Eric Rignot of NASA's Jet Propulsion Laboratory in Pasadena, California, and colleagues used satellite radar data to reveal increases in the speed of glaciers which run into the ice sheet. Three glaciers showed eightfold increases between 2000 and 2003, with another two glaciers showing a threefold increase. The ice loss amounts to more than 27 cubic kilometres per year. "The magnitude of the glacier changes illustrates the importance of ice shelves on ice sheet mass balance and contribution to sea level change," write the authors. A second paper by Ted Scambos of the University of Colorado, Boulder, used another satellite to find that four glaciers were flowing into the collapsed Larsen B ice shelf at rates two to six times faster in 2003 than in 2000. One glacier, called Hektoria, also thinned significantly a year after the collapse - its surface lowered by about 40 metres over six months. Maggie McKee http://www.newscientist.com/news/news.jsp?id=ns99996442
Models may underestimate climate swings	posted 10/1/04 2:12 PM     Models may underestimate climate swings 19:00 30 September 04 NewScientist.com news service The climate may have varied much more wildly in the past than reconstructions from tree-rings and ice-cores suggest, say climate scientists who have studied 1000 years of simulated data. The findings by Hans von Storch from the GKSS Research Institute in Geesthacht, Germany and colleagues are provoking a heated dispute. While some scientists warn that their results imply climate changes in the future could be more dramatic than predicted, others argue that their methods are flawed. “Things can get pretty incendiary,” says Thomas Crowley, a professor of earth systems science at Duke University in North Carolina, US. Current climate reconstructions rely on relating temperature records – stretching back only one century – to indicators of climate such as tree-ring growth. Using these known relationships, climate scientists can extrapolate back in time to convert environmental or geological data into temperatures. But now the new study suggests that this method may in fact be smoothing out century-long swings in the climate. Insect plagues To reach their controversial conclusion, von Storch and colleagues used a sophisticated computer model to simulate the Earth’s climate over one millennium. They extracted records of temperature at particular locations and then added “noise” to the signal to mimic the kind of data that scientist can collect in the field. For example, the thickness of tree rings is related to temperature, but it is also affected by factors such as moisture levels, or insect plagues, so there are large errors in this record. Next von Storch’s team tried to reconstruct, from this noisy data, the temperature in the northern hemisphere for each year of the 1000-year simulation. They used a statistical method that other scientists, including Michael Mann at the University of Virginia in Charlottesville, Virginia, have employed. Then they compared their estimated temperatures to those taken directly from the model. Although annual and decadal variation showed up in the reconstruction, in some cases “only 20% of the 100-year variability is recovered”. In effect, reconstructing temperatures using the noisy data, did not show up long-term climate trends. Too conservative If past climate variability has been underestimated, then predictions for future fluctuations in the temperature might be too conservative, say experts. “One of the conclusions we draw is that the climate’s sensitivity might be higher, and therefore future climate change will be greater,” says Timothy Osborn, an expert in climate variability at the University of East Anglia in Norwich, UK. But Mann says the study is flawed, because the simulation the team uses churns out larger changes in climate than most scientists think are reasonable, putting the method to a more stringent test than is fair. “I was not asked to review the von Storch paper, which I consider unfortunate,” he told New Scientist. “The important point of the study is that it shows there are objective ways of testing the methodology,” says Crowley. But arguments over the validity of the results are likely to continue, he notes. Journal reference: Science Express (online publication) Jenny Hogan http://www.newscientist.com/news/news.jsp?id=ns99996470
Dim Sun	posted 10/3/04 8:59 AM     Dim Sun Global dimming? Global warming? What's with the globe, anyway? By Kip Keen 22 Sep 2004 Raise a toast to solar radiation.The director of the Zurich-based World Radiation Monitoring Center, the organization that measures the amount of solar radiation hitting the ground around the globe, has a strange talent. Give Atsumu Ohmura a glass of white wine and tell him only its vintage, and he'll swish a mouthful and -- without referring to legs, bouquets, or mango backgrounds -- announce where the grapes were grown. His trick? The sweetness of white wine grapes is a function of solar radiation. The more sun a grape