Substream - sub_gw_impact_weather

  1. back to all global warming and energy subjects

  2. 31-01-2005 eco nws - global warming - impact - weather - temperature - 20F increase in 50 yrs! - models - grid computing - Global warming may ramp up average temperatures by 20 degrees Fahrenheit in less than 50 years, according to the first climate prediction experiment relying on the distributed computer power of 90,000 personal computers. The startling results were published this week in the journal Nature. The PCs, located in 150 countries, allowed British scientists to run more than 50,000 simulations of the future global climate, many more than the 'best ever' 128 simulations using supercomputers, said Myles Allen, chief scientist of and a physicist at Oxford University. A distributed-computing project, involves several British universities and the Hadley Centre for Climate Prediction and Research. (wired)

  3. 30-07-2005 eco nws - global warming - impact - weather - tropical storms more intense - Tropical storms have become significantly more intense in both the Atlantic and Pacific oceans during the past 30 years, according to an analysis published Sunday. Using a new 'power dissipation index' that reflects both the duration of storms and their maximum wind speeds, Kerry Emanuel, an atmospheric researcher at the Massachusetts Institute of Technology, reports that tropical storms' overall intensity has increased by about 50 percent since the mid-1970s. Although many of the fiercest storms of the past three decades haven't made landfall when they were at peak intensity, 'the near-doubling of hurricanes' power during this period should be a matter of some concern, as it's a measure of the (future) destructive potential of these storms,' Emanuel said. His paper, published online by the journal Nature, illustrates that the increases in storm intensity have been mirrored by increases in the average temperatures at the surface of tropical oceans. And while much of this warming has been attributed to decades-long swings that come and go in the Atlantic and Pacific, Emanuel said his research shows there have been increases in tropical sea surface temperatures worldwide, even outside zones that have been affected by the established patterns. Moreover, he pointed out in an interview that 'the intensity of hurricanes depends both on how much heat can be transferred from the ocean to the atmosphere, which depends on the temperature of the ocean, and on how high air rising in the eyewall can go. This depends on the temperature profile of the atmosphere.' So if climate change continues to warm both seawater and the air above it during the rest of this century, as most scientists expect, 'future warming may lead to an upward trend in tropical cyclone destructive potential, and, taking into account an increasing coastal population, (also) lead to a substantial increase in hurricane-related losses in the 21st century,'' Emanuel warned. (earth hope)

  4. 21-10-2005 eco nws - global warming - impact - weather - record - Hurricane Wilma 'strongest ever' - Hurricane Wilma, which has swelled into a dangerous Category Five storm, is the strongest hurricane ever recorded, the US National Hurricane Center says. It says the storm's barometric pressure - a measure of its strength - was the lowest on record in the Atlantic basin. Its winds of near 165mph (270km/h) and heavy rains are threatening Cuba, Mexico and the Cayman Islands. (bbc)

  5. 19-12-2005 eco nws - global warming - impact - weather - record - 2005 May Be Warmest Year Ever - In the high Arctic, deep in the Atlantic, on Africa's sunbaked plains, climate scientists are seeing change unfold before their eyes. In the global councils of power, however, change in climate policy is coming only slowly. In Geneva last week, the World Meteorological Organization reported that 2005 thus far is the second warmest year on record, extending a trend climatologists attribute at least partly to heat-trapping 'greenhouse gases' accumulating in the atmosphere. In New York, NASA's Goddard Institute projected that 2005 will surpass 1998 to end as the hottest year globally in the 125 years since reliable records have been kept. It said warming has accelerated and is now boosting the mercury every decade by more than 0.3 degrees Fahrenheit. 'The observed rapid warming thus gives urgency to discussions about how to slow greenhouse gas emissions,' the NASA researchers said. (wired)

  6. 23-01-2006 eco nws - global warming - impact - weather - Great Russian freeze spreads west - Severe cold weather gripping large parts of Russia has now spread west, causing chaos in Ukraine, Belarus, the Baltic states and Scandinavia. Officials in those countries say there is growing pressure on energy supplies, with power shortages as Russia cuts deliveries to fight the freeze at home. Dozens have died of the cold, with temperatures as low as -33C recorded. Forecasters have said that the freeze will last several more days, and could intensify in places. (bbc)

  7. 10-02-2006 eco nws - global warming - impact - weather - record - Climate 'warmest for millennium' - In the late 20th Century, the northern hemisphere experienced its most widespread warmth for 1,200 years, according to the journal Science. The findings support evidence pointing to unprecedented recent warming of the climate linked to greenhouse emissions. University of East Anglia researchers measured changes in fossil shells, tree rings, ice cores and other past temperature records or 'proxies'. They also looked at people's diaries from the last 750 years. Timothy Osborn and Keith Briffa of UEA analysed instrument measurements of temperature from 1856 onwards to establish the geographic extent of recent warming. Then they compared this data with evidence dating back as far as AD 800. The analysis confirmed periods of significant warmth in the Northern Hemisphere from AD 890 - 1170 (the so-called 'Medieval Warm Period') and for much colder periods from 1580 - 1850 (the 'Little Ice Age'). The UEA team showed that the present warm period is the most widespread temperature anomaly of any kind since the ninth century. 'The last 100 years is more striking than either [the Medieval Warm Period or Little Ice Age]. It is a period of widespread warmth affecting nearly all the records that we analysed from the same time,' co-author Timothy Osborn told the BBC. Osborn and Briffa used 14 sets of temperature records from different locations across the Northern Hemisphere. The records included long life evergreen trees growing in Scandinavia, Siberia and the Rockies which had been cored to reveal the patterns of wide and narrow tree rings over time. Wider rings related to warmer temperatures. The chemical composition of ice from cores drilled in the Greenland ice sheets revealed which years were warmer than others. The researchers used proxy data developed from the diaries of people living in the Netherlands and Belgium during the past 750 years that revealed, for example, the years when the canals froze. 'These records extend over many centuries and even thousands of years. We simply counted how many of those records indicated that, in any one year, temperatures were warmer than average for the region they came from,' said Dr Osborn. Professor John Waterhouse, director of the Environmental Sciences Research Centre Anglia Ruskin University in Cambridge commented: 'Although we're getting increasingly accurate measurements of present-day temperature, we've got nothing like that from the past to compare those with. 'There's much uncertainty in past reconstructions. You've got to look at the reconstructed data in the past in light of the likely errors that those data have.' But he added: 'As we get more and more evidence in, it is looking as if the current period is the warmest for over 1,000 years.' In November, Science published a paper showing atmospheric levels of the greenhouse gases carbon dioxide and methane are higher now than at any time in the past 650,000 years. (bbc)

  8. 03-08-2006 eco nws - global warming - impact - heat waves - weather - French heatwave claims 64 lives - Sixty-four people have died in France in a heatwave that has gripped much of Europe for two weeks. French officials said 40 of the victims were over 75 years old. There are fears that the death toll could rise, even though the high temperatures, above 35C (95F) in some places, dropped after overnight storms. The heat has brought back memories of 2003, when some 15,000 people died in France, most of them elderly. (bbc)

  9. 03-08-2006 eco nws - global warming - impact - heat waves - weather - Deaths mount amid California heat - The heatwave that has been baking California since mid-July is being blamed for more than 130 deaths across the state, the authorities have said. Many of the deaths have been in the Central Valley, where temperatures have reached 46C (115F) in some areas. Among the worst-hit areas is Fresno, where the local mortuary is struggling to deal with dozens of bodies. The heat has also hit the agriculture sector, killing 25,000 cattle and 700,000 poultry, farmers say. (bbc)

  10. 19-10 2006 eco nws - global warming - impact - system - weather - report - Going to the Extremes Expect a Warmer, Wetter World this Century - Recent episodes of deadly heat in the United States and Europe, long dry spells across the U.S. West, and heavy bursts of rain and snow across much of North America and Eurasia hint at longer-term changes to come, according to a new study based on several of the world's most advanced climate models. Much of the world will face an enhanced risk of heat waves, intense precipitation, and other weather extremes, conclude scientists from the National Center for Atmospheric Research (NCAR), Texas Tech University, and Australia's Bureau of Meteorology Research Centre. The new study, 'Going to the Extremes,' will appear in the December issue of the journal Climatic Change. Many previous studies have looked at how average temperature or rainfall might change in the next century as greenhouse gases increase. However, the new research looks more specifically at how weather extremes could change. 'It's the extremes, not the averages, that cause the most damage to society and to many ecosystems,' says NCAR scientist Claudia Tebaldi, lead author for the report. 'We now have the first model-based consensus on how the risk of dangerous heat waves, intense rains, and other kinds of extreme weather will change in the next century.' The study is one of the first analyses to draw on extensive and sophisticated computer modeling recently carried out for the Intergovernmental Panel on Climate Change. The IPCC's next assessment report will be released early in 2007. Tebaldi and colleagues based their work on simulations from nine different climate models for the periods 1980�1999 and 2080�2099. The simulations were created on supercomputers at research centers in France, Japan, Russia, and the United States. Each model simulated the 2080-2099 interval three times, varying the extent to which greenhouse gases accumulate in the atmosphere. These three scenarios were used to account for uncertainty over how fast society may act to reduce emissions of carbon dioxide and other greenhouse gases over coming decades. From the model output, the scientists computed 10 different indices of climate extremes, with 5 related to temperature and 5 to moisture. For instance, a frost days index measures how many days per year temperatures dip below 32 degrees Fahrenheit, while a dry days index measures the length of each year's longest consecutive string of days without rain or snow. Because the impact of a given index can be stronger in one climatic zone than another, the authors expressed the results in terms of statistical significance at each location. For all three greenhouse-gas scenarios, the models agree that by 2080-2099: * The number of extremely warm nights and the length of heat waves will increase significantly over nearly all land areas across the globe. During heat waves, very warm nights are often associated with fatalities because people and buildings have less chance to cool down overnight. / * Most areas above about 40 degrees north will see a significant jump in the number of days with heavy precipitation (days with more than 0.40 inches). This includes the northern tier of U.S. states, Canada, and most of Europe. / * Dry spells could lengthen significantly across the western United States, southern Europe, eastern Brazil, and several other areas. Dry spells are one of several factors in producing and intensifying droughts. / * The average growing season could increase significantly across most of North America and Eurasia. / Most of these trends are significantly weaker for the lowest-emission scenario than for the moderate and high-emission scenarios. Thus, the authors add, lowering the output of greenhouse gases over the next century should reduce the risk that the most severe changes will occur. The research was supported by the National Science Foundation, which is NCAR's primary sponsor, as well as by the U.S. Department of Energy and Environmental Protection Agency. (science blog)

  11. 19-01-2007 Europa - Nederland nws - eco nws - global warming - impact - weather - Northern Europe swept by storms - A violent storm lashing northern Europe has hit the Netherlands and Germany after passing over Britain and France. At least 28 people have been killed, as the high winds have sent debris flying and brought down trees and power lines. Ten people were killed in Britain as rain and gusts of wind up to 99mph (159km/h) swept much of the country. In Germany, hurricane-force winds claimed at least seven lives. Other deaths were reported in France, Poland, the Czech Republic and the Netherlands. The severe weather has thrown transport systems into chaos, with hundreds of flight, rail and ferry cancellations and roads and schools ordered closed. (bbc)

  12. 16-03-2007 eco nws - global warming - impact - weather - record - Winter warmth breaks all records - Winter in the northern hemisphere this year has been the warmest since records began more than 125 years ago, a US government agency says. The combined land and ocean surface temperature from December to February was 0.72C (1.3F) above average. The National Oceanic and Atmospheric Administration said El Nino, a seasonal warming of parts of the Pacific Ocean, had also contributed to the warmth. But it didn't see the temperature rise as evidence of global warming. The NOAA said that temperatures are continuing to rise by a fifth of a degree every decade. The 10 warmest years on record have occurred since 1995. Weather experts predict that 2007 could be the hottest year on record. 'Contributing factors were the long-term trend toward warmer temperatures as well as a moderate El Nino in the Pacific,' said Jay Lawrimore of NOAA's National Climatic Data Center. He added: 'We don't say this winter is evidence of the influence of greenhouse gases.' (bbc)

  13. 18-05-2010 eco nws - global warming - impact - weather - record - april 2010 - Warmest April Global Temperature on Record, NOAA Says - ScienceDaily (May 18, 2010) � The combined global land and ocean surface temperature was the warmest on record for both April and for the period from January-April, according to NOAA. Additionally, last month's average ocean surface temperature was the warmest on record for any April, and the global land surface temperature was the third warmest on record. The monthly analysis from NOAA's National Climatic Data Center, which is based on records going back to 1880, is part of the suite of climate services that NOAA provides government, business and community leaders so they can make informed decisions. Global Temperature Highlights -- April 2010: * The combined April global land and ocean average surface temperature was the warmest on record at 58.1�F (14.5�C), which is 1.37�F (0.76�C) above the 20th century average of 56.7�F (13.7�C). * The combined global land and ocean average surface temperature was the warmest on record for January-April at 56.0�F (13.3�C), which is 1.24�F (0.69�C) above the 20th century average. * Separately, the global ocean surface temperature was 1.03�F (0.57�C) above the 20th century average of 60.9�F (16.0�C) and the warmest on record for April. The warmth was most pronounced in the equatorial portions of the major oceans, especially the Atlantic. * The global land surface temperature was 2.32�F (1.29�C) above the 20th century average of 46.5 �F (8.1�C) -- the third warmest on record for April. Warmer-than-normal conditions dominated the globe, with the most prominent warmth in Canada, Alaska, the eastern United States, Australia, South Asia, northern Africa and northern Russia. Cooler-than-normal places included Mongolia, Argentina, far eastern Russia, the western contiguous United States and most of China. * El Ni�o Southern Oscillation (ENSO) weakened in April, as sea-surface temperature anomalies decreased across the equatorial Pacific Ocean. The weakening contributed significantly to the warmth observed in the tropical belt and the warmth of the overall ocean temperature for April. According to NOAA's Climate Prediction Center, El Ni�o is expected to continue through June. Other Highlights * Arctic sea ice was below normal for the 11th consecutive April, covering an average of 5.7 million square miles (14.7 million square kilometers). This is 2.1 percent below the 1979-2000 average extent and the 15th smallest April extent since records began in 1979. It was, however, the largest April Arctic sea ice extent since 2001. * Antarctic sea ice extent in April was near average, just 0.3 percent below the 1979-2000 average. * Based on NOAA satellite observations, snow cover extent was the fourth-lowest on record (since 1967), and below the 1967-2010 average for the Northern Hemisphere for the seventh consecutive April. Warmer-than-normal conditions over North America, Europe and parts of Russia contributed to the small snow footprint. * The North American snow cover extent for the month was the smallest on record for April. It also was the largest negative anomaly, meaning difference below the long-term average, on record for any month. * According to Australia's Bureau of Meteorology, Victoria and Tasmania had their warmest 12-month period since national records began. * According to the Beijing Climate Center, China experienced its coolest April since 1961. Liaoning, Jilin and Shandong had their coolest April on record. Hebei, Anhui and Jiangsu had their second coolest April since records began in 1951. * China had its wettest April since 1974 and Tibet had its wettest April since records began in 1951. Meanwhile, Germany had its second-driest April on record since 1901, behind 2007, according to the German Meteorological Service (Deutscher Wetterdienst). Scientists, researchers, and leaders in government and industry use NOAA's monthly reports to help track trends and other changes in the world's climate. This climate service has a wide range of practical uses, from helping farmers know what and when to plant, to guiding resource managers with critical decisions about water, energy and other vital assets.

  14. 15-06-2010 eco nws - global warming - impact - weather - europe - More Cold and Snowy Winters to Come in Europe, Eastern Asia and Eastern North America - ScienceDaily (June 15, 2010) � A warmer Arctic climate is influencing the air pressure at the North Pole and shifting wind patterns on our planet. We can expect more cold and snowy winters in Europe, eastern Asia and eastern North America. "Cold and snowy winters will be the rule, rather than the exception," says Dr James Overland of the NOAA/Pacific Marine Environmental Laboratory in the United States. Dr Overland is at the International Polar Year Oslo Science Conference (IPY-OSC) to chair a session on polar climate feedbacks, amplification and teleconnections, including impacts on mid-latitudes. - Loss of sea ice causes major climate change - Continued rapid loss of sea ice will be an important driver of major change in the world's climate system in the years to come. "While the emerging impact of greenhouse gases is an important factor in the changing Arctic, what was not fully recognised until now is that a combination of an unusual warm period due to natural variability, loss of sea ice reflectivity, ocean heat storage and changing wind patterns working together has disrupted the memory and stability of the Arctic climate system, resulting in greater ice loss than earlier climate models predicted," says Dr Overland. "The exceptional cold and snowy winter of 2009-2010 in Europe, eastern Asia and eastern North America is connected to unique physical processes in the Arctic," he says. - Irreversible change - The Arctic is warming more than twice as fast as the rest of the planet. This is known as Arctic amplification -- a much debated phenomenon at the IPY-OSC, where 2400 polar scientists have gathered to discuss the huge amount of research and new findings which are the direct result of the International Polar Year. The changes are happening a great deal faster than the scientific community expected. Given the recent reduction of the area of multi-year sea ice and reduced ice thickness, it is unlikely that the Arctic can return to its previous condition. "The changes are irreversible," says Dr Overland. - A landmark event - "The IPY Oslo Science Conference is a landmark event in our understanding of the Arctic climate," says Dr Overland, who is chairing one of the sessions on climate at the conference. More than 80 scientific papers have been submitted discussing Arctic amplification and its impacts.

  15. 17-06-2010 eco nws - global warming - impact - weather - record - may 2010 - May 2010 Global Temperature Is Warmest on Record; Spring and January-May Also Post Record Breaking Temps - ScienceDaily (June 17, 2010) � The combined global land and ocean surface temperature was the warmest on record for May, March-May (Northern Hemisphere spring-Southern Hemisphere autumn), and the period January-May according to NOAA. Worldwide average land surface temperature for May and March-May was the warmest on record while the global ocean surface temperatures for both May and March-May were second warmest on record, behind 1998. The monthly analysis from NOAA's National Climatic Data Center, which is based on records going back to 1880, is part of the suite of climate services NOAA provides government, business and community leaders so they can make informed decisions. /// Global Highlights -- May 2010: * The combined global land and ocean surface temperature for May was the warmest on record, at 1.24�F (0.69�C) above the 20th century average of 58.6�F (14.8�C). * The global land surface temperature for May was 1.87�F (1.04�C) above the 20th century average of 52.0�F (11.1�C) -- the warmest on record. * The May worldwide ocean temperature was the second warmest on record, behind 1998. The temperature anomaly was 0.99�F (0.55�C) above the 20th century average of 61.3�F (16.3�C). * Warm temperatures were present over most of the globe's land areas. The warmest temperature anomalies occurred in eastern North America, eastern Brazil, Eastern Europe, southern Asia, eastern Russia, and equatorial Africa. The Chinese province of Yunnan had its warmest May since 1951. Numerous locations in Ontario, Canada had their warmest May on record. * Anomalously cool conditions were present across western North America, northern Argentina, interior Asia, and Western Europe. Germany had its coolest May since 1991 and its 12th coolest May on record. /// Global Highlights -- March-May 2010: * The combined global land and ocean average surface temperature for the March-May season was 58.0�F (14.4�C), which is the warmest such period on record and 1.31�F (0.73�C) above the 20th century average of 56.7�F (13.7�C). * The worldwide land surface temperature for March-May was 2.20�F (1.22�C) above the 20th century average of 46.4 �F (8.1�C) -- the warmest on record. * The worldwide ocean surface temperature was 0.99�F (0.55�C) above the 20th century average of 61.0�F (16.1�C) and the second warmest March-May on record, behind 1998. * Very warm temperatures were present across eastern and northern North America, northern Africa, Eastern Europe, southern Asia, and parts of Australia. Tasmania tied its warmest March-May period on record. The Northeastern U.S. also had its warmest March-May period on record. Conversely, cool temperatures enveloped the western U.S. and eastern Asia. * Western Europe was particularly dry for its spring season. For the United Kingdom, it was the driest spring since 1984, and the twelfth driest since the UK record began in 1910. /// Other Highlights: * Arctic sea ice covered an average of 5.06 million square miles (13.1 million square kilometers) during May. This is 3.7 percent below the 1979-2000 average extent and the ninth-smallest May footprint since records began in 1979. During May 2010, Arctic sea ice melted 50 percent faster than the average May melting rate, according to the National Snow & Ice Data Center. * Antarctic sea ice extent in May was 7.3 percent above the 1979-2000 average, resulting in the fourth largest May extent on record. * Northern Hemisphere snow cover extent during May 2010 was a record low at 4.3 million square kilometers below the long-term average. North America and Eurasia both had record-low snow extents for the month. Northern Hemisphere March-May snow cover extent was fourth smallest on record, while the North American (including Greenland) snow cover extent for spring (March-May) 2010 was the smallest on record. Scientists, researchers, and leaders in government and industry use NOAA's monthly reports to help track trends and other changes in the world's climate. This climate service has a wide range of practical uses, from helping farmers know what and when to plant, to guiding resource managers with critical decisions about water, energy and other vital assets.

  16. 29-09-2010 eco nws - global warming - impact - weather - temperature - Climate Accord Loopholes Could Spell 4.2-Degree Rise in Temperature and End of Coral Reefs by 2100 - ScienceDaily (Sep. 29, 2010) � A global temperature increase of up to 4.2 � C and the end of coral reefs could become reality by 2100 if national targets are not revised in the Copenhagen Accord, the international pledge which was agreed at last year's Copenhagen's COP15 climate change conference. Just ahead of the next United Nations Climate Change Conference, which starts on 4 October in Tianjin, China, a new report published Sept. 29 in IOP Publishing's Environmental Research Letters describes how, due to lack of global action to date, only a small chance remains for keeping the global temperature increase down to 2 � C as set as a target in the Accord. Looking at individual countries' agreed targets for emission levels, the report shows that many developed countries such as the USA and the European Union have set their aims very low, aiming at reaching emission levels just a few percent lower than 1990 levels by 2020. Only Japan and Norway are aiming to drastically reduce their emission to 25% and 30 to 40% below 1990 levels respectively. Presenting their results in Environmental Research Letters, a group of international researchers from seven European research centres, has also found that even if nations would agree to a 50% reduction of emission levels by 2050 -- a target that strong international agreements would greatly facilitate -- there would still only be a less than 50% chance to keep global warming below 2 � C. Rising global temperature levels would not be the only consequence of failing to raise the ambition level of future global emission reductions. Increasing ocean acidification, a direct result of growing atmospheric CO2 levels, could lead to a rapid decline of coral reefs and the marine ecosystem in the 21st century. As the researchers write, urgent action is necessary, "It is clear from this analysis that higher ambitions for 2020 are necessary to keep the options for 2 � C and 1.5 � C open without relying on potentially infeasible reduction rates after 2020. "In addition, the absence of a mid-century emission goal -- towards which Parties as a whole can work and which serve as a yardstick of whether interim reductions by 2020 and 2030 are on the right track -- is a critical deficit in the overall ambition level of the Copenhagen Accord." Professor Dan Kammen, Editor-in-Chief of Environmental Research Letters said, "The researchers provide an important lens on the ecological impacts and both social and ecological costs of inaction on climate protection."

  17. 19-10-2010 eco nws - global warming - impact - weather - drought - Drought May Threaten Much of Globe Within Decades, Analysis Predicts - ScienceDaily (Oct. 19, 2010) � The United States and many other heavily populated countries face a growing threat of severe and prolonged drought in coming decades, according to a new study by National Center for Atmospheric Research (NCAR) scientist Aiguo Dai. The detailed analysis concludes that warming temperatures associated with climate change will likely create increasingly dry conditions across much of the globe in the next 30 years, possibly reaching a scale in some regions by the end of the century that has rarely, if ever, been observed in modern times. Using an ensemble of 22 computer climate models and a comprehensive index of drought conditions, as well as analyses of previously published studies, the paper finds most of the Western Hemisphere, along with large parts of Eurasia, Africa, and Australia, may be at threat of extreme drought this century. In contrast, higher-latitude regions from Alaska to Scandinavia are likely to become more moist. Dai cautioned that the findings are based on the best current projections of greenhouse gas emissions. What actually happens in coming decades will depend on many factors, including actual future emissions of greenhouse gases as well as natural climate cycles such as El Ni�o. The new findings appear as part of a longer review article in Wiley Interdisciplinary Reviews: Climate Change. The study was supported by the National Science Foundation, NCAR's sponsor. "We are facing the possibility of widespread drought in the coming decades, but this has yet to be fully recognized by both the public and the climate change research community," Dai says. "If the projections in this study come even close to being realized, the consequences for society worldwide will be enormous." While regional climate projections are less certain than those for the globe as a whole, Dai's study indicates that most of the western two-thirds of the United States will be significantly drier by the 2030s. Large parts of the nation may face an increasing risk of extreme drought during the century. Other countries and continents that could face significant drying include: * Much of Latin America, including large sections of Mexico and Brazil * Regions bordering the Mediterranean Sea, which could become especially dry * Large parts of Southwest Asia * Most of Africa and Australia, with particularly dry conditions in regions of Africa * Southeast Asia, including parts of China and neighboring countries The study also finds that drought risk can be expected to decrease this century across much of Northern Europe, Russia, Canada, and Alaska, as well as some areas in the Southern Hemisphere. However, the globe's land areas should be drier overall. "The increased wetness over the northern, sparsely populated high latitudes can't match the drying over the more densely populated temperate and tropical areas," Dai says. A climate change expert not associated with the study, Richard Seager of Columbia University's Lamont Doherty Earth Observatory, adds: "As Dai emphasizes here, vast swaths of the subtropics and the midlatitude continents face a future with drier soils and less surface water as a result of reducing rainfall and increasing evaporation driven by a warming atmosphere. The term 'global warming' does not do justice to the climatic changes the world will experience in coming decades. Some of the worst disruptions we face will involve water, not just temperature." - A portrait of worsening drought - Previous climate studies have indicated that global warming will probably alter precipitation patterns as the subtropics expand. The 2007 assessment by the Intergovernmental Panel on Climate Change (IPCC) concluded that subtropical areas will likely have precipitation declines, with high-latitude areas getting more precipitation. In addition, previous studies by Dai have indicated that climate change may already be having a drying effect on parts of the world. In a much-cited 2004 study, he and colleagues found that the percentage of Earth's land area stricken by serious drought more than doubled from the 1970s to the early 2000s. Last year, he headed up a research team that found that some of the world's major rivers are losing water. In his new study, Dai turned from rain and snow amounts to drought itself, and posed a basic question: how will climate change affect future droughts? If rainfall runs short by a given amount, it may or may not produce drought conditions, depending on how warm it is, how quickly the moisture evaporates, and other factors. Droughts are complex events that can be associated with significantly reduced precipitation, dry soils that fail to sustain crops, and reduced levels in reservoirs and other bodies of water that can imperil drinking supplies. A common measure called the Palmer Drought Severity Index classifies the strength of a drought by tracking precipitation and evaporation over time and comparing them to the usual variability one would expect at a given location. Dai turned to results from the 22 computer models used by the IPCC in its 2007 report to gather projections about temperature, precipitation, humidity, wind speed, and Earth's radiative balance, based on current projections of greenhouse gas emissions. He then fed the information into the Palmer model to calculate the PDSI index. A reading of +0.5 to -0.5 on the index indicates normal conditions, while a reading at or below -4 indicates extreme drought. The most index ranges from +10 to -10 for current climate conditions, although readings below -6 are exceedingly rare, even during short periods of time in small areas. By the 2030s, the results indicated that some regions in the United States and overseas could experience particularly severe conditions, with average decadal readings potentially dropping to -4 to -6 in much of the central and western United States as well as several regions overseas, and -8 or lower in parts of the Mediterranean. By the end of the century, many populated areas, including parts of the United States, could face readings in the range of -8 to -10, and much of the Mediterranean could fall to -15 to -20. Such readings would be almost unprecedented. Dai cautions that global climate models remain inconsistent in capturing precipitation changes and other atmospheric factors, especially at the regional scale. However, the 2007 IPCC models were in stronger agreement on high- and low-latitude precipitation than those used in previous reports, says Dai. There are also uncertainties in how well the Palmer index captures the range of conditions that future climate may produce. The index could be overestimating drought intensity in the more extreme cases, says Dai. On the other hand, the index may be underestimating the loss of soil moisture should rain and snow fall in shorter, heavier bursts and run off more quickly. Such precipitation trends have already been diagnosed in the United States and several other areas over recent years, says Dai. "The fact that the current drought index may not work for the 21st century climate is itself a troubling sign," Dai says.

  18. 17-11-2010 eco nws - global warming - impact - weather - winter - europe - Global Warming Could Cool Down Northern Temperatures in Winter - ScienceDaily (Nov. 17, 2010) � The overall warming of Earth's northern half could result in cold winters, new research shows. The shrinking of sea-ice in the eastern Arctic causes some regional heating of the lower levels of air -- which may lead to strong anomalies in atmospheric airstreams, triggering an overall cooling of the northern continents, according to a study recently published in the Journal of Geophysical Research. "These anomalies could triple the probability of cold winter extremes in Europe and northern Asia," says Vladimir Petoukhov, lead author of the study and climate scientist at the Potsdam Institute for Climate Impact Research. "Recent severe winters like last year's or the one of 2005-06 do not conflict with the global warming picture, but rather supplement it." The researchers base their assumptions on simulations with an elaborate computer model of general circulation, ECHAM5, focusing on the Barents-Kara Sea north of Norway and Russia where a drastic reduction of ice was observed in the cold European winter of 2005-06. Those surfaces of the sea lacking the ice cover lose a lot of warmth to the normally cold and windy arctic atmosphere. What the researchers did was to feed the computer with data, gradually reducing the sea ice cover in the eastern Arctic from 100 percent to 1 percent in order to analyse the relative sensitivity of wintertime atmospheric circulation. "Our simulations reveal a rather pronounced nonlinear response of air temperatures and winds to the changes of sea-ice cover," Petoukhov, a physicist, says. "It ranges from warming to cooling to warming again, as sea ice decreases." An abrupt transition between different regimes of the atmospheric circulation in the sub-polar and polar regions may be very likely. Warming of the air over the Barents-Kara Sea seems to bring cold winter winds to Europe. "This is not what one would expect," Petoukhov says. "Whoever thinks that the shrinking of some far away sea-ice won't bother him could be wrong. There are complex teleconnections in the climate system, and in the Barents-Kara Sea we might have discovered a powerful feedback mechanism." Other approaches to the issue of cold winters and global warming referring to reduced sun activity or most recently the gulf stream "tend to exaggerate the effects," Petoukhov says. The correlation between these phenomena and cold winters is relatively weak, compared to the new findings referring to the processes in the Barents-Kara Sea. Petoukhov also points out that during the cold winter of 2005-06 with temperatures of ten degrees below the normal level in Siberia, no anomalies in the north Atlantic oscillation have been observed. These are fluctuations in the difference of atmospheric pressure between the Icelandic low and the Azores high which are commonly associated with temperature anomalies over Europe. But temperatures in the eastern arctic were up to 14 degrees above normal level. However, distinct anomalies in the north Atlantic oscillation could interact with sea-ice decrease, the study concludes. One could amplify the other and more anomalies would be the result. Petoukhov's study is not about tomorrow's weather forecast but about longtime probabilities of climate change. "I suppose nobody knows," he says, "how harsh this year's winter will be."

  19. 14-12-2010 eco nws - global warming - impact - weather - drought - usa - Hot With Decades of Drought: Expectations for Southwestern United States - ScienceDaily (Dec. 14, 2010) � An unprecedented combination of heat plus decades of drought could be in store for the Southwest sometime this century, suggests new research from a University of Arizona-led team. A 60-year drought like that of the 12th Century could be in our future. To come to this conclusion, the team reviewed previous studies that document the region's past temperatures and droughts. "Major 20th century droughts pale in comparison to droughts documented in paleoclimatic records over the past two millennia," the researchers wrote. During the Medieval period, elevated temperatures coincided with lengthy and widespread droughts. By figuring out when and for how long drought and warm temperatures coincided in the past, the team identified plausible worst-case scenarios for the future. Such scenarios can help water and other resource managers plan for the future, the team wrote. "We're not saying future droughts will be worse than what we see in the paleo record, but we are saying they could be as bad," said lead author Connie A. Woodhouse, a UA associate professor of geography and regional development. "However, the effects of such a worst-case drought, were it to recur in the future, would be greatly intensified by even warmer temperatures." The team's paper is part of the special feature, "Climate Change and Water in Southwestern North America," scheduled for publication Dec. 13 in the Early Online edition of the Proceedings of the National Academy of Sciences. The paper by Woodhouse and her colleagues is titled, "A 1,200-year perspective of 21st century drought in the southwestern North America." Co-authors are Glen M. MacDonald of the University of California, Los Angeles; Dave W. Stahle of the University of Arkansas in Fayetteville; and Edward R. Cook of Lamont-Doherty Earth Observatory of Columbia University, Palisades, N.Y. The analysis in the current paper includes previous research by Woodhouse, co-author David M. Meko and others that documented past droughts that lasted several decades. Moreover, some of those droughts occurred during times of relatively warm temperatures. Within the last 2,000 years, there have been several periods of severe and sustained drought that affected much of western North America. Droughts that are accompanied by warm temperatures have more severe impacts on ecosystems, said Meko, an associate research professor in the UA's Laboratory of Tree-Ring Research. During the Medieval period, temperatures were about 1.8 degrees Fahrenheit (1 C) above the long-term average. Average temperatures in the Southwest have been warmer than that since 1990 and are projected to increase at least another 3.6 F (2 C) by 2100, Woodhouse said. The most severe warm-climate drought in the Southwest within the last 1,200 years was 60 years long and occurred during the mid-12th century, according to research by Meko and others. That drought covered most of the western U.S. and northern Mexico. For a 25-year period during that drought, Colorado River flow averaged 15 percent below normal, according to the tree-ring-based reconstruction of stream flow at Lees Ferry. For every 1.8 degree Fahrenheit (1 C) of warming in the future, Colorado River flow is projected to decrease between two and eight percent, Woodhouse and her co-authors wrote. The Colorado River supplies water for cities and agriculture in seven western states in the U.S. and two states in northwestern Mexico. Los Angeles, Las Vegas, Denver, Phoenix, Tucson and Albuquerque are among the many cities dependent on Colorado River water. "Even without warming, if you had one of those medieval droughts now, the impact would be devastating," she said. "Our water systems are not built to sustain us through that length of drought." Noting that the Colorado River flows recorded at Lees Ferry from 2000 to 2009 are the lowest on record, Woodhouse said the current drought could be part of a longer dry period. The instrumental record from Lees Ferry goes back to 1906. "As this drought unfolds you can't really evaluate it until you're looking back in time," she said. In recent decades, temperatures have been higher than during the previous 1,200 years, and future temperatures are predicted to be even warmer, Woodhouse said. In addition, other research predicts that changes in atmospheric circulation will reduce the amount of winter precipitation the Southwest receives in the future, she said. "The bottom line is, we could have a Medieval-style drought with even warmer temperatures," Woodhouse said.

  20. 14-01-2011 eco nws - global warming - impact - weather - record - 2005 - 2010 - 2010 Tied for Warmest Year on Record, NASA Research Finds - ScienceDaily (Jan. 14, 2011) � Global surface temperatures in 2010 tied 2005 as the warmest on record, according to an analysis released Jan. 12, 2011 by researchers at NASA's Goddard Institute for Space Studies (GISS) in New York. The two years differed by less than 0.018 degrees Fahrenheit. The difference is smaller than the uncertainty in comparing the temperatures of recent years, putting them into a statistical tie. In the new analysis, the next warmest years are 1998, 2002, 2003, 2006, 2007 and 2009, which are statistically tied for third warmest year. The GISS records begin in 1880. The analysis found 2010 approximately 1.34 F warmer than the average global surface temperature from 1951 to 1980. To measure climate change, scientists look at long-term trends. The temperature trend, including data from 2010, shows the climate has warmed by approximately 0.36 F per decade since the late 1970s. "If the warming trend continues, as is expected, if greenhouse gases continue to increase, the 2010 record will not stand for long," said James Hansen, the director of GISS. The analysis produced at GISS is compiled from weather data from more than 1000 meteorological stations around the world, satellite observations of sea surface temperature and Antarctic research station measurements. A computer program uses the data to calculate temperature anomalies -- the difference between surface temperature in a given month and the average temperature for the same period during 1951 to 1980. This three-decade period acts as a baseline for the analysis. The resulting temperature record closely matches others independently produced by the Met Office Hadley Centre in the United Kingdom and the National Oceanic and Atmospheric Administration's National Climatic Data Center. The record temperature in 2010 is particularly noteworthy, because the last half of the year was marked by a transition to strong La Ni�a conditions, which bring cool sea surface temperatures to the eastern tropical Pacific Ocean. "Global temperature is rising as fast in the past decade as in the prior two decades, despite year-to-year fluctuations associated with the El Ni�o-La Ni�a cycle of tropical ocean temperature," Hansen and colleagues reported in the Dec. 14, 2010, issue of Reviews of Geophysics. A chilly spell also struck this winter across northern Europe. The event may have been influenced by the decline of Arctic sea ice and could be linked to warming temperatures at more northern latitudes. Arctic sea ice acts like a blanket, insulating the atmosphere from the ocean's heat. Take away that blanket, and the heat can escape into the atmosphere, increasing local surface temperatures. Regions in northeast Canada were more than 18 degrees warmer than normal in December. The loss of sea ice may also be driving Arctic air into the middle latitudes. Winter weather patterns are notoriously chaotic, and the GISS analysis finds seven of the last 10 European winters warmer than the average from 1951 to 1980. The unusual cold in the past two winters has caused scientists to begin to speculate about a potential connection to sea ice changes. "One possibility is that the heat source due to open water in Hudson Bay affected Arctic wind patterns, with a seesaw pattern that has Arctic air downstream pouring into Europe," Hansen said. For more information about GISS's surface temperature record, visit: A Warming World Global Temperatures Animation

  21. 22-02-2011 eco nws - global warming - impact - crops - food safety - Climate Change Affecting Food Safety - ScienceDaily (Feb. 22, 2011) � Climate change is already having an effect on the safety of the world's food supplies and unless action is taken it's only going to get worse, a Michigan State University professor told a symposium at this year's meeting of the American Association for the Advancement of Science. Ewen Todd, an MSU professor of advertising, public relations and retailing, organized a session titled "How Climate Change Affects the Safety of the World's Food Supply" at which several nationally known experts warned that food safety is already an issue and will worsen unless climate change is confronted. "Accelerating climate change is inevitable with implications for animal products and crops," said Todd, who also is an AAAS Fellow. "At this point, the effects of climate change on food safety are poorly understood." However, Todd said there are already a number of examples of climate change taking its toll on the world's food supply. One is Vibrio, a pathogen typically found in warm ocean water which is now becoming more common in the north as water temperatures rise. "It's been moving further up the coast these past few years," he said. "There was an outbreak of it near Alaska in 2005 when water temperature reached 15 degrees Celsius." Todd also said that extreme weather -- droughts and heavy rains -- is having an impact on the world's food supply. In some areas crops are being wiped out, resulting in higher prices and other issues. "Mycotoxins are molds that can sometimes cause illness in humans, and where you have drought and starvation there can be a mycotoxin problem," he said. "That's because people will store their meager resources of crops for longer than they should."

  22. 21-08-2011 eco nws - global warming - impact - oceans - north icelandic jet - nij - weather - Newly Discovered Icelandic Current Could Change North Atlantic Climate Picture - ScienceDaily (Aug. 21, 2011) � An international team of researchers, including physical oceanographers from the Woods Hole Oceanographic Institution (WHOI), has confirmed the presence of a deep-reaching ocean circulation system off Iceland that could significantly influence the ocean's response to climate change in previously unforeseen ways. The current, called the North Icelandic Jet (NIJ), contributes to a key component of the Atlantic Meridional Overturning Circulation (AMOC), also known as the "great ocean conveyor belt," which is critically important for regulating Earth's climate. As part of the planet's reciprocal relationship between ocean circulation and climate, this conveyor belt transports warm surface water to high latitudes where the water warms the air, then cools, sinks, and returns towards the equator as a deep flow. Crucial to this warm-to-cold oceanographic choreography is the Denmark Strait Overflow Water (DSOW), the largest of the deep, overflow plumes that feed the lower limb of the conveyor belt and return the dense water south through gaps in the Greenland-Scotland Ridge. For years it has been thought that the primary source of the Denmark Overflow is a current adjacent to Greenland known as the East Greenland Current. However, this view was recently called into question by two oceanographers from Iceland who discovered a deep current flowing southward along the continental slope of Iceland. They named the current the North Icelandic Jet and hypothesized that it formed a significant part of the overflow water. Now, in a paper published in the Aug. 21 online issue of the journal Nature Geoscience, the team of researchers -- including the two Icelanders who discovered it -- has confirmed that the Icelandic Jet is not only a major contributor to the DSOW but "is the primary source of the densest overflow water." "In our paper we present the first comprehensive measurements of the NIJ," said Robert S. Pickart of WHOI, one of the authors of the study. "Our data demonstrate that the NIJ indeed carries overflow water into Denmark Strait and is distinct from the East Greenland Current. We show that the NIJ constitutes approximately half of the total overflow transport and nearly all of the densest component. The researchers used a numerical model to hypothesize where and how the NIJ is formed. "We've identified a new paradigm," he said. "We're hypothesizing a new, overturning loop" of warm water to cold. The results, Pickart says, have "important ramifications" for ocean circulation's impact on climate. Climate specialists have been concerned that the conveyor belt is slowing down due to a rise in global temperatures. They suggest that increasing amounts of fresh water from melting ice and other warming-related phenomena are making their way into the northern North Atlantic, where it could freeze, which would prevent the water from sinking and decrease the need for the loop to deliver as much warm water as it does now. Eventually, this could lead to a colder climate in the northern hemisphere. While this scenario is far from certain, it is critical that researchers understand the overturning process, he said, to be able to make accurate predictions about the future of climate and circulation interaction. "If a large fraction of the overflow water comes from the NIJ, then we need to re-think how quickly the warm-to-cold conversion of the AMOC occurs, as well as how this process might be altered under a warming climate," Pickart said. "These results implicate local water mass transformation and exchange near Iceland as central contributors to the deep limb of the Atlantic Meridional Overturning Circulation, and raise new questions about how global ocean circulation will respond to future climate change," said Eric Itsweire, program director in the U.S. National Science Foundation (NSF)'s Division of Ocean Sciences, which funded the research. The Research Council of Norway also funded the analysis of the data. Pickart and a team of scientists from the U.S., Iceland, Norway, and the Netherlands are scheduled to embark on Aug. 22 on a cruise aboard the WHOI-operated R/V Knorr to collect new information on the overturning in the Iceland Sea. "During our upcoming cruise on the Knorr we will, for the first time, deploy an array of year-long moorings across the entire Denmark Strait to quantify the NIJ and distinguish it from the East Greenland Current," Pickart said. "Then we will collect shipboard measurements in the Iceland Sea to the north of the mooring line to determine more precisely where and how the NIJ originates." In addition to Pickart, authors of the Nature Geoscience study include Michael A. Spall, and Daniel J. Torres of WHOI, lead author Kjetil V�ge, a graduate of the MIT-WHOI joint program now with University of Bergen, Norway, Svein �sterhus and Tor Eldevik, also of the University of Bergen, Norway, and H��inn Valdimarsson and Steingr�mur J�nsson -- the two discoverers of the NIJ -- of the Marine Research Institute in Reykjavik, Iceland.

  23. 11-10-2011 eco nws - global warming - impact - weather - heat waves - drought - blame - can be done - Laying the Blame for Extreme Weather - ScienceDaily (Oct. 11, 2011) � Floods, tornadoes, droughts and wildfires: They are all weather-related, but blaming the latest meteorological disaster on climate change has always been a tricky matter that climate scientists have been shy to do. After all, how can you point to a specific and local event, such as a tornado or dry spell, and say it is caused by something as long-term and huge as global warming? "That's been the mantra of the community and I think it's wrong," said climate scientist Kevin Trenberth of the National Center for Atmospheric Research (NCAR) in Colorado. Trenberth and other climate scientists will be giving presentations that connect extreme weather over the past decade to climate change at a session of The Geological Society of America meeting in Minneapolis on October 11, 2011. The session, entitled Extreme Climate and Weather Events: Past, Present and Future, begins with Trenberth's presentation, The Russian Heat Wave and Other Climate Extremes of 2010. He cautions, however, that the harsh weather certainly didn't stop with 2011 and they all can be traced to the place where global warming stores its heat, year after year: the oceans. The sea surface temperatures near all the extreme flooding events of 2010 were at record levels, Trenberth explains. That includes the Caribbean, Gulf of Mexico, N. Atlantic and the Indian Ocean. "All of the storms are being formed in an environment that is warmer and wetter than before," said Trenberth. "The main thing that has happened with climate change is that you have changed the environment." Specifically, the waters are about one degree Fahrenheit warmer than pre-1970 values, leading to air that's four percent wetter. All that additional moisture and heat in the air feeds storms. "That's the climate change kicker. It's the extra nudge that indeed makes you break records." Another way of looking at it is in terms of the odds of extreme weather events. Extreme weather is always possible, after all. But with warmer oceans, such events are easier to create. "We're loading the dice in favor of extreme weather events," said Trenberth. The same goes for droughts and subsequent wild fires. They are the flip-side of the extreme storms in a global atmosphere. While unusually wet monsoons were flooding Pakistan in 2010, the same event helped to block moisture from reaching southern Russia. That led to heat waves and fires. This kind of situation reinforces cyclonic and anticyclonic patterns in the atmosphere which make some areas wetter and others drier and hotter. "So there are dynamical connections," Trenberth said. "You can't disrupt one part of the atmosphere without getting effects in the whole." And with the history and continued releases of carbon dioxide and other greenhouse gases, plus pollution into the atmosphere, there is no doubt that the system is being disrupted, he said.

  24. 30-11-2011 eco nws - global warming - impact - weather - views - Climate Change May Happen More Quickly Than Expected - ScienceDaily (Nov. 30, 2011) � As global temperatures continue to rise at an accelerated rate due to deforestation and the burning of fossil fuels, natural stores of carbon in the Arctic are cause for serious concern, researchers say. In an article scheduled to be published Dec. 1 in the journal Nature, a survey of 41 international experts led by University of Florida ecologist Edward Schuur shows models created to estimate global warming may have underestimated the magnitude of carbon emissions from permafrost over the next century. Its effect on climate change is projected to be 2.5 times greater than models predicted, partly because of the amount of methane released in permafrost, or frozen soil. "We're talking about carbon that's in soil, just like in your garden where there's compost containing carbon slowly breaking down, but in permafrost it's almost stopped because the soil is frozen," Schuur said. "As that soil warms up, that carbon can be broken down by bacteria and fungi, and as they metabolize, they are releasing carbon and methane, greenhouse gases that cause warmer temperatures." As a result of plant and animal remains decomposing for thousands of years, organic carbon in the permafrost zone is distributed across 11.7 million square miles of land, an amount that is more than three times larger than previously estimated. The new number is mainly based on evidence the carbon is stored much deeper as the result of observations, soil measurements and experiments. "We know the models are not yet giving us the right answer -- it's going to take time and development to make those better, and that process is not finished yet," Schuur said. "It's an interesting exercise in watching how scientists, who are very cautious in their training, make hypotheses about what our future will look like. The numbers are significant, and they appear like they are plausible and they are large enough for significant concern, because if climate change goes 20 or 30 percent faster that we had predicted already, that's a pretty big boost." The survey, which was completed following a National Science Foundation-funded Permafrost Carbon Network workshop about six months ago, proposed four warming scenarios until 2040, 2100 and 2300. Researchers were asked to predict the amount of permafrost likely to thaw, how much carbon would be released, and what amount would be methane, which has much more warming potential than carbon dioxide. The occurrence of carbon in northern soils is natural and the chemical does not have an effect on climate if it remains underground, but when released as a greenhouse gas it can add to climate warming. However, humans could slow warming temperatures as the result of greenhouse gas emissions from deforestation and the burning of fossil fuels, which are what speed up the process of permafrost thaw. "Even though we're talking about a place that is very far away and seems to be out of our control, we actually have influence over what happens based on the overall trajectory of warming. If we followed a lower trajectory of warming based on controlling emissions from the burning of fossil fuels, it has the effect of slowing the whole process down and keeping a lot more carbon in the ground," Schuur said. "Just by addressing the source of emissions that are from humans, we have this potential to just keep everything closer to its current state, frozen in permafrost, rather than going into the atmosphere." The survey shows that by 2100, experts believe the amount of carbon released will be 1.7 to 5.2 times greater than previous models predict, under scenarios where Arctic temperatures rise 13.5 degrees Fahrenheit. Some predicted effects of global warming include sea level rise, loss of biodiversity as some organisms are unable to migrate as quickly as the climate shifts and more extreme weather events that could affect food supply and water resources. "This new research shows that the unmanaged part of the biosphere has a major role in determining the future trajectory of climate change," said Stanford University biology professor Christopher Field, who was not involved in the study. "The implication is sobering. Whatever target we set for atmospheric CO2, this new research means we will need to work harder to reach it. But of course, limiting the amount of climate change also decreases the climate damage from permafrost melting." When carbon is released from the ground as a result of thawing permafrost, there is no way of trapping the gases at the source, so action to slow its effect must be taken beforehand. "If you think about fossil fuel and deforestation, those are things people are doing, so presumably if you had enough will, you could change your laws and adjust your society to slow some of that down," Schuur said. "But when carbon starts being emitted from the permafrost, you can't immediately say, 'OK, we've had enough of this, let's just stop doing it,' because it's a natural cycle emitting carbon whether you like it or not. Once we start pushing it, it's going to be releasing under its own dynamic."

  25. 05-12-2011 eco nws - global warming - impact - weather - temperature - Global Warming 'Not Slowing Down,' Say Researchers - ScienceDaily (Dec. 5, 2011) � Researchers have added further clarity to the global climate trend, proving that global warming is showing no signs of slowing down and that further increases are to be expected in the next few decades. They revealed the true global warming trend by bringing together and analysing the five leading global temperature data sets, covering the period from 1979 to 2010, and factoring out three of the main factors that account for short-term fluctuations in global temperature: El Ni�o,volcanic eruptions and variations in the Sun's brightness. After removing these known short-term fluctuations, the researchers, statisticians and climate experts from Tempo Analytics and the Potsdam Institute for Climate Impact Research, showed that the global temperature has increased by 0.5�C in the past 30 years. In all of the five global data sets, 2009 and 2010 were the two hottest years. In the average over all five data sets, 2010 is the hottest year on record. Their study, published Dec. 6 in IOP Publishing's journal Environmental Research Letters, comes at a time when global warming is at the forefront of the political agenda, with the United Nations Framework Convention on Climate Change (UNFCCC) currently taking place in Durban. It is well known that temperatures have been rising since the early 20th Century and the effects have become visible in shrinking mountain glaciers, accelerating ice loss and sea level rise. In recent years, however, there have been claims by some that the global warming trend has slowed or even paused over the last decade or so. "Our approach shows that the idea that the global warming trend has slowed or even paused over the last decade or so is a groundless misconception. It shows that differences between the five data sets reside, to a large extent, in their short-term variability and not in the climatic trend. After the variability is removed, all five data sets are very similar," said study co-author Stefan Rahmstorf. As global temperatures are constantly being measured by several different scientific teams, each adopting different methods for dealing with their data, it is clear that no single record is free of complications, uncertainties and corrections. By bringing together and analysing the five records -- three surface records and two lower-troposphere records -- the researchers were able to clarify the discrepancies between each one and, when factoring out the naturally occurring variability, show the excellent agreement between all five data sets. The three surface temperature data sets analysed by the researchers were from NASA, the National Oceanic and Atmospheric Administration (NOAA) and the Hadley Centre/Climate Research Unit in the UK. Data representing the lower troposphere temperatures was based on satellite microwave sensors. El Ni�o is a naturally and irregularly occurring warming of surface ocean waters in the eastern tropical Pacific, whilst solar variation is the change in the amount of radiation emitted by the sun, dominated by an approximately 11-year-long cycle. Volcanic eruptions predominantly have a cooling effect lasting a few years, due to the very tiny erupted particles and droplets shielding light from hitting Earth. "The unabated warming is powerful evidence that we can expect further temperature increase in the next few decades, emphasizing the urgency of confronting the human influence on the climate," says Grant Foster, lead author of the study.

  26. 12-01-2012 eco nws - global warming - impact - weather - colder winters - Cold Winters Caused by Warmer Summers, Research Suggests - ScienceDaily (Jan. 12, 2012) — Scientists have offered up a convincing explanation for the harsh winters recently experienced in the Northern Hemisphere; increasing temperatures and melting ice in the Arctic regions creating more snowfall in the autumn months at lower latitudes. Their findings may throw light on specific weather incidents such as the extremely harsh Florida winter of 2010 which ended up killing a host of tropical creatures, as well as the chaos-causing snow that fell on the UK in December 2010. Published January 13, in IOP Publishing's journal Environmental Research Letters, this new research suggests that the trend of increasingly cold winters over the past two decades could be explained by warmer temperatures in the autumn having a marked effect on normal weather patterns, causing temperatures to plummet in the following winter. The strongest winter cooling trends were observed in the eastern United States, southern Canada and much of northern Eurasia, which the researchers, based at Atmospheric and Environmental Research (AER), the University of Massachusetts and the University of Alaska Fairbanks, believe cannot be entirely explained by the natural variability of the climate system. Their results showed strong warming throughout July, August and September in the Arctic, which continued through the autumn and, according to their observational data, appeared to enhance the melting of sea ice. This warmer atmosphere, combined with melting sea ice, allows the Arctic atmosphere to hold more moisture and increases the likelihood of precipitation over more southern areas such as Eurasia, which, in the freezing temperatures, would fall as snow. Indeed, the researchers' observations showed that the average snow coverage in Eurasia has increased over the past two decades. They believe the increased snow cover has an intricate effect on the Arctic Oscillation -- an atmospheric pressure pattern in the mid- to high-latitudes -- causing it to remain in the "negative phase." In the "negative phase," high pressure resides over the Arctic region, pushing colder air into mid-latitude regions, such as the United States and northern Canada, and giving the observed colder winters. The lead author of the study, Judah Cohen, said: "In my mind there is no doubt that the globe is getting warmer and this will favour warmer temperatures in all seasons and in all locations; however, I do think that the increasing trend in snow cover has led to regional cooling as discussed in the paper and I see no reason why this won't continue into the near future. Also if it continues to get much warmer in the fall, precipitation that currently falls as snow will fall as rain instead, eliminating the winter cooling." It is also deduced that one of the main reasons conventional climate models fail to pick up on this observed winter cooling is their failure to account for the variability of snow cover, which, as demonstrated in this study, can greatly improve the accuracy of seasonal, and lengthier, forecasts. "We show in the paper how using the snow cover in a seasonal forecast can provide a more skilful or accurate forecast. Without correctly simulating the coupling of winter climate patterns and the variability of snow fall, the models currently used by Government centres miss an important influence on winter and will therefore continue to be deficient in predicting winter weather on seasonal time scales, and even longer decadal time scales," continued Cohen.

  27. 18-01-2012 eco nws - global warming - impact - weather - oceans - Climate Balancing: Sea-Level Rise Vs. Surface Temperature Change Rates - ScienceDaily (Jan. 18, 2012) — Engineering our way out of global climate warming may not be as easy as simply reducing the incoming solar energy, according to a team of University of Bristol and Penn State climate scientists. Designing the approach to control both sea level rise and rates of surface air temperature changes requires a balancing act to accommodate the diverging needs of different locations. "Basic physics and past observations suggest that reducing the net influx of solar energy will cool the Earth," said Peter J. Irvine, graduate student, University of Bristol, UK, and participant in the Worldwide Universities Network Research Mobility Programme to Penn State. "However, surface air temperatures would respond much more quickly and sea levels will respond much more slowly." Current solar radiation management approaches include satellites that block the sun, making Earth's surface more reflective or mimicking the effects of volcanoes by placing aerosol particles in the upper atmosphere. "These solar radiation management approaches could be cheaper than reducing carbon dioxide emissions," said Klaus Keller, associate professor of geosciences, Penn State. "But they are an imperfect substitute for reducing carbon dioxide emissions and carry considerable risks." How well they work at reducing sea level rise or surface air temperatures depends on how they are implemented. "Strategies designed to reverse sea-level rise differ from the strategies designed to limit the rate of temperature changes," said Ryan Sriver, research associate in geosciences, Penn State. To stop or reverse sea-level rise, the incoming solar radiation would have to be decreased rapidly, but this approach would produce rapid cooling. Adopting a more gradual approach would reduce the risks due to rapid cooling, but would allow for considerable sea-level rise. The researchers note that people living close to sea level are likely more concerned about sea-level rise than about the rates of surface temperature changes. In contrast, those living far from the oceans, are likely more concerned about rates of surface temperature changes that can influence agricultural or energy usage. The researchers used a model to analyze the tension between controlling sea level rise and rates of surface temperature changes. They ran 120 scenarios with differing combinations of solar radiation management (SRM) including one called "business as usual," which has no SRM. They note that their model includes many approximations. For example, it does not include a mechanistic representation of ice sheets. They also did not consider scenarios that combine solar radiation management and reducing carbon dioxide emissions. They report in the current issue of Nature Climate Change that the forcing required to stop sea-level rise could cause a rapid cooling with a rate similar to the peak business-as-usual warming rate. "While abrupt cooling may sound like a good idea, it could be more damaging than the increasing temperatures caused by increasing carbon dioxide," said Keller. "The rate of cooling can be a problem if it exceeds the capacity of the plants and animals to adapt," said Sriver. Another consideration when implementing solar radiation management approaches is that these approaches can require a long-term commitment. The researchers showed that "termination of solar radiation management was found to produce warming rates up to five times greater than the maximum rates under the business-as-usual scenario, whereas sea-level rise rates were only 30 percent higher." To avoid such harsh changes, should SRM be discontinued, requires a slow phase out over many decades. This places a commitment on future generations.

  28. 19-01-2012 eco nws - global warming - impact - weather - 2011 - record - no - but with 10 warmest on record - NASA Finds 2011 Ninth-Warmest Year On Record - ScienceDaily (Jan. 19, 2012) — The global average surface temperature in 2011 was the ninth warmest since 1880, according to NASA scientists. The finding continues a trend in which nine of the 10 warmest years in the modern meteorological record have occurred since the year 2000. NASA's Goddard Institute for Space Studies (GISS) in New York, which monitors global surface temperatures on an ongoing basis, released an updated analysis that shows temperatures around the globe in 2011 compared to the average global temperature from the mid-20th century. The comparison shows how Earth continues to experience warmer temperatures than several decades ago. The average temperature around the globe in 2011 was 0.92 degrees F (0.51 C) warmer than the mid-20th century baseline. "We know the planet is absorbing more energy than it is emitting," said GISS Director James E. Hansen. "So we are continuing to see a trend toward higher temperatures. Even with the cooling effects of a strong La Niña influence and low solar activity for the past several years, 2011 was one of the 10 warmest years on record." The difference between 2011 and the warmest year in the GISS record (2010) is 0.22 degrees F (0.12 C). This underscores the emphasis scientists put on the long-term trend of global temperature rise. Because of the large natural variability of climate, scientists do not expect temperatures to rise consistently year after year. However, they do expect a continuing temperature rise over decades. The first 11 years of the 21st century experienced notably higher temperatures compared to the middle and late 20th century, Hansen said. The only year from the 20th century in the top 10 warmest years on record is 1998. Higher temperatures today are largely sustained by increased atmospheric concentrations of greenhouse gases, especially carbon dioxide. These gases absorb infrared radiation emitted by Earth and release that energy into the atmosphere rather than allowing it to escape to space. As their atmospheric concentration has increased, the amount of energy "trapped" by these gases has led to higher temperatures. The carbon dioxide level in the atmosphere was about 285 parts per million in 1880, when the GISS global temperature record begins. By 1960, the average concentration had risen to about 315 parts per million. Today it exceeds 390 parts per million and continues to rise at an accelerating pace. The temperature analysis produced at GISS is compiled from weather data from more than 1,000 meteorological stations around the world, satellite observations of sea surface temperature and Antarctic research station measurements. A publicly available computer program is used to calculate the difference between surface temperature in a given month and the average temperature for the same place during 1951 to 1980. This three-decade period functions as a baseline for the analysis. The resulting temperature record is very close to analyses by the Met Office Hadley Centre in the United Kingdom and the National Oceanic and Atmospheric Administration's National Climatic Data Center in Asheville, N.C. Hansen said he expects record-breaking global average temperature in the next two to three years because solar activity is on the upswing and the next El Niño will increase tropical Pacific temperatures. The warmest years on record were 2005 and 2010, in a virtual tie. "It's always dangerous to make predictions about El Niño, but it's safe to say we'll see one in the next three years," Hansen said. "It won't take a very strong El Niño to push temperatures above 2010."