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Southern California wildfires track with global warming, not population trends - 0 views

  • USGS researchers found that southern California is the only part of the state that has experienced significant increases in wildfires over the last five decades. Analysis shows that this increase is linked to the rise in atmospheric temperature. Past studies suggest that wildfire activity has increased throughout the western United States. USGS researchers wanted to know whether this pattern has region-specific variations and causes. For the analysis, they divided California into five climate zones and looked at how number of wildfires and area burned have changed over the past 49 years. But this study did not find statewide increases in wildfires. Only southern California experienced increases in fires and area burned. Curiously, the increases are not linked to that region’s enormous change in population growth. However, for northern California, analysis shows that wildfire trends have links to population trends. This research gives new perspectives on wildfire trends in California. The results will inform urban and natural resource planners on their long-term outlook on wildfire management.
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Troubling ice melt in East Antarctica - 0 views

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    Report in Science: "Three studies, using different remote-sensing methods, show that East Antarctica has already begun to lose ice. A survey of laser altimetry data from the ICESat satellite, published in Nature in October 2009, found ice thinning in several spots along the East Antarctic coast at annual rates as high as nearly 2 meters. Another study, published in Nature Geoscience in November 2009, used the gravity-sensing GRACE satellites and found two areas along the East Antarctic coast each losing about 13 km3 of ice per year. A 2008 study in Nature Geoscience that compared ice flux off the edges of the continent with new accumulation of snow in the interior found a loss of about 10 km3 of ice per year at two areas." "Three studies, using different remote-sensing methods, show that East Antarctica has already begun to lose ice. A survey of laser altimetry data from the ICESat satellite, published in Nature in October 2009, found ice thinning in several spots along the East Antarctic coast at annual rates as high as nearly 2 meters. Another study, published in Nature Geoscience in November 2009, used the gravity-sensing GRACE satellites and found two areas along the East Antarctic coast each losing about 13 km3 of ice per year. A 2008 study in Nature Geoscience that compared ice flux off the edges of the continent with new accumulation of snow in the interior found a loss of about 10 km3 of ice per year at two areas." "It's too early to know what the ice loss in East Antarctica really means, says Isabella Velicogna, a remote-sensing specialist at NASA's Jet Propulsion Laboratory in Pasadena, California. "What is important is to see what's generating the mass loss," she says. Reductions in snowfall, for example, might reflect short-term weather cycles that could reverse at any time. But thinning caused by accelerating glaciers-as seen in West Antarctica-would warrant concern."
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Fog over San Francisco thins by a third due to climate change - 0 views

  • The coastal fog along the Californian coast has declined by a third over the past 100 years – the equivalent of three hours cover a day, new research shows. And it is not just bad for scenery, the reduction in the cooling effect of the fog could damage the health of the huge Redwood Forests nearby.
  • "Since 1901, the average number of hours of fog along the coast in summer has dropped from 56 per cent to 42 per cent, which is a loss of about three hours per day," said the study leader Dr James Johnstone at the University of California. He said that it was unclear whether this is part of a natural cycle of the result of human activity, but the fog is receding because of a reduction in the difference between the temperature of the sea and the land. "A cool coast and warm interior is one of the defining characteristics of California's coastal climate, but the temperature difference between the coast and interior has declined substantially in the last century, in step with the decline in summer fog," he added.
  • Professor Todd Dawson, co-author, said the decline could be disastrous for the nearby ecosystems.
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  • "Fog prevents water loss from Redwoods in summer, and is really important for both the tree and the forest," he said. "If the fog is gone, we might not have the Redwood forests we do now."
Hunter Cutting

Climate Change Beginning to Disrupt Agriculture in the U.S: - 0 views

  • Climate Change Is Beginning to Disrupt Agriculture
  • Climate variability has already affected rains, droughts and temperatures in several parts of the United States, said Cynthia Rosenzweig, a senior research scientist with NASA's Goddard Institute for Space Studies. "We are already seeing climate change." "We are seeing the expansion of drying," said Rosenzweig, as she brought up a slide showing precipitation measurements across the United States. The measurements, comparing values from 1958 through 2008, showed significant reductions in rainfall across large portions of the Northwest and Southeast. Idaho, Washington, Montana, Georgia and Florida had some of the most drastic changes in rainfall on the map. However, the opposite is not good either, she said, adding that increased soil moisture in some areas could potentially harbor insects and other pests. And, in general, "crops do not like to have their feet wet." Aside from concerns about rainfall, local temperature is also extremely important for crop performance. The reproductive development in many important grains is a process sensitive to temperature, said Paul Gepts, a professor of agronomy at the University of California, Davis. Some plants need cold winters One of the potential side effects of climate change is a trend toward milder winters in some regions. Vital plants, Gepts said, require a cold winter in order to properly develop their seeds for the next season. Rosenzweig agreed. Heat waves, at odd times of the year, affect the proper development of proteins within corn kernels, she said. "It is like scrambling eggs." Gepts also presented a number of well-known strategies for mitigating some of the possible economic effects of climate change on agriculture. Aside from breeding plants to be more drought-, heat- and pest-resistant, he also suggested varying the types of crops maintained on a particular site on the basis of environmental suitability.
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    Scientific American:
Hunter Cutting

Declining rainfall over 30 years helped fuel conflicts in sub-Sahara - 0 views

  • Some experts call the genocide in Darfur the world's first conflict caused by climate change. After all, the crisis was sparked, at least in part, by a decline in rainfall over the past 30 years just as the region's population doubled, pitting wandering pastoralists against settled farmers for newly scarce resources, such as arable land.
  • Agricultural economist Marshall Burke of the University of California, Berkeley and his colleagues have analyzed the history of conflict in sub-Saharan Africa between 1980 and 2002 in a new paper in Proceedings of the National Academy of Sciences.
  • "We find that civil wars were much more likely to happen in warmer-than-average years, with one degree Celsius warmer temperatures in a given year associated with a 50 percent higher likelihood of conflict in that year," Burke says. The implication: because average temperatures may warm by at least one degree C by 2030, "climate change could increase the incidences of African civil war by 55 percent by 2030, and this could result in about 390,000 additional battle deaths if future wars are as deadly as recent wars."
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  • In fact, temperature change offered a better prediction of impending conflict in the 40 countries surveyed than even changes in rainfall, despite the fact that agriculture in this region is largely dependent on such precipitation. Burke and his fellow authors argue that this could be because many staple crops in the region are vulnerable to reduced yields with temperature changes—10 to 30 percent drops per degree C of warming.
  • "If temperature rises, crop yields decline and rural incomes fall, and the disadvantaged rural population becomes more likely to take up arms," Burke says. "Fighting for something to eat beats starving in their fields."
  • Whereas 23 years in 40 countries provides a relatively large data set, it does not exclude other possible explanations, such as violent crime increasing with temperature rise, a drop in farm labor productivity or population growth. "Fast population growth could create resource shortage problems, as well," notes geographer David Zhang of the University of Hong Kong, who previously analyzed world history back to A.D. 1400 to find linkages between war and temperature change. Those results were also published in 2007 in Proceedings of the National Academy of Sciences. But "the driver for this linkage," Zhang says," is resource shortage, mainly agricultural production, which is caused by climate change." Burke and his colleagues specifically excluded records from prior to 1980, because of the conflict rampant in the wake of Africa's emerging colonial independence after World War II. "A lag of a couple of decades would leave sufficient time for post-independence turmoil to wear out," Burke argues. "We took the approach that the best analogue to the next few decades were the last few decades."
  • Proving the link—and providing a specific mechanism for the increase in conflict, whether agricultural productivity or otherwise—remains the next challenge. "I believe that the historical experience of human society of climate change would provide us [with] the evidence of how climate cooling and warming during the last thousand years created human crisis, and also the lessons for human adaptive choices for climate change," Zhang notes. "We feel that we have very clearly shown the strong link between temperature increases and conflict risk," Burke adds. But "what interventions will make climate-induced conflict less likely?"
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    Article in Scientific American, based on study published in the Proceedings of the National Academy of Sciences. Study also addresses role of rising temperatures
Hunter Cutting

West, South bake in unseasonably early heat wave - 0 views

  • the heat so far this June has been exceptional -- and, in some cases, record-breaking.
  • A strong upper-level high-pressure system, more reminiscent of midsummer than early June, has been responsible for the unusual spike in temperatures, which has extended from the Desert Southwest through the Southern Plains and into the deep South. The heat peaked in the Southwest on Sunday and Monday. The temperature soared to 110 degrees in Las Vegas on Sunday -- the earliest 110-degree reading on record -- and temperatures approached 120 degrees in Death Valley on both Sunday and Monday. The National Weather Service issued excessive-heat warnings and heat advisories for southern Nevada, the deserts of California and portions of Arizona, warning residents of the need to remain hydrated and limit outdoor activity.
  • In Las Vegas, the high temperature will be close to 105 degrees today and near 100 degrees on Wednesday, which will mark seven consecutive days with 100-plus temperatures.The unusually hot weather has been persistent in the Southern Plains, Missouri Valley and parts of the deep South so far in June as well. Temperatures have averaged five to eight degrees above normal across this region, including a 100-degree temperature in Dallas on Saturday, and heat advisories remain in effect in parts of Louisiana.
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    An AOL report on a record breaking heat wave bringing in an uncharacteristically early start to the summer season for the Southwestern United States. This event is consistent with the long-term trend of a change in the seasons driven by climate change.
Hunter Cutting

Flooding now regular event for Mulegé river in Baja - 0 views

  • A picturesque Baja town has been hammered repeatedly by the escalating tempo of flooding from tropical storms.
  • “Before we got here in 1982, there had been two floods on record,” Christopher, a retired Californian and Rotary Club member, told me. “The floods of 1914 and 1955. Then since 2006, we had three floods — almost one every year! I’m starting to get tired of rebuilding the roof and everything else.”
  • Why the frequency of floods now after so many quiet years? “I think it’s global warming,” said Christopher.
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  • There is agreement on one issue: excess greenhouse gases in the atmosphere will increase the intensity of storms (in general) and especially rainfall, since warmer conditions allow more water vapor to be sucked from the air. The higher risk of flooding is especially problematic for coastal areas because of storm surge. Researchers analyzing streamflows in large basins and GHG trends conclude that so-called 100-year floods likely will become more frequent.
Hunter Cutting

Big snow storms not inconsistent with - and may be amplified by - a warming planet - 0 views

  • there was a detailed study of “the relationships of the storm frequencies to seasonal temperature and precipitation conditions” for the years “1901–2000 using data from 1222 stations across the United States.”  The 2006 study, “Temporal and Spatial Characteristics of Snowstorms in the Contiguous United States” (Changnon, Changnon, and Karl [of National Climatic Data Center], 2006) found we are seeing more northern snow storms and that we get more snow storms in warmer years: The temporal distribution of snowstorms exhibited wide fluctuations during 1901–2000, with downward 100-yr trends in the lower Midwest, South, and West Coast. Upward trends occurred in the upper Midwest, East, and Northeast, and the national trend for 1901–2000 was upward, corresponding to trends in strong cyclonic activity…..
  • Results for the November–December period showed that most of the United States had experienced 61%– 80% of the storms in warmer-than-normal years. Assessment of the January–February temperature conditions again showed that most of the United States had 71%–80% of their snowstorms in warmer-than-normal years. In the March–April season 61%–80% of all snowstorms in the central and southern United States had occurred in warmer-than-normal years…. Thus, these comparative results reveal that a future with wetter and warmer winters, which is one outcome expected (National Assessment Synthesis Team 2001), will bring more snowstorms than in 1901–2000. Agee (1991) found that long-term warming trends in the United States were associated with increasing cyclonic activity in North America, further indicating that a warmer future climate will generate more winter storms.
  • the U.S. Global Change Research Program (USGCRP) U.S. Climate Impacts Report from 2009, which reviewed the literature and concluded: Cold-season storm tracks are shifting northward and the strongest storms are likely to become stronger and more frequent.
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  • Large-scale storm systems are the dominant weather phenomenon during the cold season in the United States. Although the analysis of these storms is complicated by a relatively short length of most observational records and by the highly variable nature of strong storms, some clear patterns have emerged.112 [Kunkel et al., 2008] Storm tracks have shifted northward over the last 50 years as evidenced by a decrease in the frequency of storms in mid-latitude areas of the Northern Hemisphere, while high-latitude activity has increased. There is also evidence of an increase in the intensity of storms in both the mid- and high-latitude areas of the Northern Hemisphere, with greater confidence in the increases occurring in high latitudes.112 [Kunkel et al., 2008] The northward shift is projected to continue, and strong cold season storms are likely to become stronger and more frequent, with greater wind speeds and more extreme wave heights.68 [Gutowski et al, 2008]
  • The northward shift in storm tracks is reflected in regional changes in the frequency of snowstorms. The South and lower Midwest saw reduced snowstorm frequency during the last century. In contrast, the Northeast and upper Midwest saw increases in snowstorms, although considerable decade-to-decade variations were present in all regions, influenced, for example, by the frequency of El Niño events.112 [Kunkel et al., 2008]
  • Then we have this apparently as yet unpublished research presented by Dr James Overland of the NOAA/Pacific Marine Environmental Laboratory at the recent International Polar Year Oslo Science Conference (IPY-OSC) where he was chairing “a session on polar climate feedbacks, amplification and teleconnections, including impacts on mid-latitudes.” “Cold and snowy winters will be the rule, rather than the exception,” says Dr James Overland…. 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.
  • Even though these storms occurred during warmest winter on record, I think the best way to talk about it until Overland publishes his work is the way NCAR’s Kevin Trenberth did on NPR (audio here): RENEE MONTAGNE, host:  With snow blanketing much of the country, the topic of global warming has become the butt of jokes. Climate skeptics built an igloo in Washington, D.C. during last weeks storm and dedicated it to former Vice President Al Gore, who’s become the public face of climate change. There was also a YouTube video called “12 Inches of Global Warming” that showed snowplows driving through a blizzard.For scientists who study the climate, it’s all a bit much. As NPRs Christopher Joyce reports, they’re trying to dig out. CHRISTOPHER JOYCE: Snowed-in Washington is where much of the political debate over climate change happens. So it did not go unnoticed when a Washington think-tank that advocates climate action had to postpone a climate meeting last week because of inclement weather. That kind of irony isnt lost on climate scientists. Most don’t see a contradiction between a warming world and lots of snow. Heres Kevin Trenberth, a prominent climate scientist at the National Center for Atmospheric Research in Colorado. Mr. KEVIN TRENBERTH (Scientist, National Center for Atmospheric Research): The fact that the oceans are warmer now than they were, say, 30 years ago, means there’s about, on average, 4 percent more water vapor lurking around over the oceans than there was, say, in the 1970s. JOYCE: Warmer water means more water vapor rises up into the air. And what goes up, must come down. Mr. TRENBERTH: So one of the consequences of a warming ocean near a coastline like the East Coast and Washington, D.C., for instance, is that you can get dumped on with more snow, partly as a consequence of global warming. JOYCE: And Trenberth notes that you don’t need very cold temperatures to get big snow. In fact, when the mercury drops too low, it may be too cold to snow. There’s something else fiddling with the weather this year: a strong El Nino. That’s the weather pattern that, every few years, raises itself up out of the western Pacific Ocean and blows east to the Americas. It brings heavy rains and storms to California and the South and Southeast. It also pushes high-altitude jet streams farther south, which brings colder air with them. Trenberth also says El Nino can lock in weather patterns like a meteorological highway, so that storms keep coming down the same track. True, those storms have been big ones – record breakers. But meteorologist Jeff Masters, with the Web site Weather Underground, says it’s average temperatures — not snowfall — that really measure climate change. There’s more water vapor lurking around the oceans, and whatever the proximate cause of any one snow storm, there is little doubt that global warming means the overwhelming majority of East Coast storms will be sweeping in more moisture and dumping it on the ground.
Hunter Cutting

9 of 25 Pika populations in Nevada/Utah gone as temps rise - 0 views

  • As temperatures have risen across the American West, scientists who study the pika have discovered that it is disappearing from lower elevations. In the Sierra Nevada, for instance, biologists at the University of California, Berkeley, found that the pika had moved upslope 500 feet to cooler climes over the past 90 years. Another study determined that nine of 25 pika populations in the Great Basin of Nevada and Utah have vanished over the past century, with surviving pikas migrating up 900 feet.
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