July 13, 2006, 10:10 PM CT

Land-use Practices Impact Earth System

In a paper reported in the July 2006 issue of Global Change Biology, University of New Hampshire researchers George Hurtt, Steve Frolking, and coauthors show that land-use activities over the last 300 years have substantially altered the land surface in ways that are likely to have had profound effects on the Earth system. Land-use changes have impacted some 42-68 percent of the global land surface, as per the study, which used historical records, satellite data, and computer modeling to reconstruct 216 different global land-use reconstructions to derive the most comprehensive picture to-date.

"This is the first global land-use history description that's designed specifically to allow global carbon and climate models to assess the impacts of land-use history both on the past and current sources and sinks of carbon and climate," says Hurtt, assistant professor of natural resources at the UNH Institute for the Study of Earth, Oceans, and Space (EOS) and Department of Natural Resources.

As per Hurtt, this global land-use data will allow the next generation of coupled carbon-climate models, known as Earth-system models, to include the most advanced representations of land-use practices yet, including the first mapped estimates of the effects of shifting agriculture, logging, and secondary recovering lands.........

Posted by: Tyler      Permalink         Source

July 13, 2006, 6:44 PM CT

Impact Of Polluted Skies On Climate

NASA researchers have determined that the formation of clouds is affected by the lightness or darkness of air pollution particles. This also impacts Earth's climate.

In a breakthrough study published recently in the online edition of Science, researchers explain why aerosols -- tiny particles suspended in air pollution and smoke -- sometimes stop clouds from forming and in other cases increase cloud cover. Clouds not only deliver water around the globe, they also help regulate how much of the sun's warmth the planet holds. The capacity of air pollution to absorb energy from the sun is the key.

"When the overall mixture of aerosol particles in pollution absorbs more sunlight, it is more effective at preventing clouds from forming. When pollutant aerosols are lighter in color and absorb less energy, they have the opposite effect and actually help clouds to form," said Lorraine Remer of NASA's Goddard Space Flight Center, Greenbelt, Md. Remer worked closely with the study's lead author, the late Yoram Kaufman of Goddard, on prior research into this perplexing "aerosol effect".

With this new understanding, researchers working to predict how the Earth's climate is changing will be able to take a big step forward. The effect of the planet's constantly changing cloud cover has long been a problem for climate scientists. How clouds change in response to greenhouse-gas warming and air pollution will have a major impact on future climate.........

Posted by: Tyler      Permalink

July 13, 2006, 0:03 AM CT

Parana River Delta

The Parana River delta is a huge forested marshland about 20 miles (32 km) northwest of Buenos Aires, Argentina. The area is a very popular tour destination. Guided boat tours can be taken into this vast labyrinth of marsh and trees. The Parana River delta is one of the world's greatest bird-watching destinations.........

Posted by: Tyler      Permalink

July 12, 2006, 10:49 PM CT

Tiny Tremors And Earthquakes

The elusive science of earthquake prediction has been reinvigorated in recent years with the discovery of "non-volcanic tremors"--faint vibrations that originate deep inside active fault zones.

Since 2002, these mysterious signals have been recorded in seismically active sections of Japan, the Pacific Northwest and California's San Andreas Fault.

Seismologists think that non-volcanic tremors may eventually prove useful in forecasting major earthquakes. But to accomplish that, they first have to figure out exactly where the signals are located--a daunting task, because the vibrations are not impulsive, and hence their origin is difficult to locate.

Now, for the first time, seismologists from Stanford University and the University of Tokyo say they have finally pinpointed the source and likely cause of at least part of the tremor. Writing in the July 13 edition of the journal Nature, the research team concludes that some of the non-volcanic signals emanating from a Japanese fault zone are probably the by-products of "silent earthquakes"--slow-moving temblors that displace the ground without shaking it.

"Silent earthquakes do not generate seismic waves, so you don't feel them," said Gregory C. Beroza, professor of geophysics at Stanford and co-author of the Nature study. "However, it's possible that they foreshadow powerful seismic temblors of magnitude 8 and larger. Therefore, knowing when a silent event has occurred could contribute to seismic hazard forecasting. We think that non-volcanic tremor signals may be useful in monitoring silent quakes, which aren't that easy to detect."........

Posted by: Tyler      Permalink         Source

July 11, 2006, 8:46 PM CT

Preserving a Wild West

When Americans think of the Wild West, we often conjure cowboys and ranchlands, grizzly bears and mountains, or a great plain where the buffalo once roamed. But Dr. Joel Berger, senior scientist with the Wildlife Conservation Society's North America Program, thinks of pronghorn. As the fastest land animal in North America, these lithe antelope migrate annually across tremendous distances, at speeds of up to 55 miles per hour.

Given the significant size of the pronghorn population-which numbers almost half a million in Wyoming alone-their plight has not inspired great sympathy. But this distinctly American species has become a casualty of one of the most provocative issues of our time: the national energy crisis. As Western lands become increasingly subject to development, the conservation of Rocky Mountain wildlife is losing ground-literally.

Berger and his team in the WCS Teton Field Office, which includes scientists Dr. Kim Murray Berger and Dr. Jon Beckmann, are working on two projects to carve out a home for pronghorn in the face of the impending human footprint. One is the creation of a permanently protected migration corridor for the antelope. This ambitious project would conserve the most extensive trail of its kind in the Western Hemisphere, and one that has been in use since the end of the last Ice Age. The scientists' other project is a study on how natural gas development in the Rockies influences the pronghorn that winter there. Shell Exploration & Production Company, Ultra Resources, Inc., and other energy groups are funding this five-year investigation, an important collaboration between the industry and conservation sectors.........

Posted by: Tyler      Permalink         Source

July 11, 2006, 7:11 AM CT

Key Migrant In Yellowstone Ecosystem

A mammal that embarks on the longest remaining overland migration in the continental United States could vanish from the ecosystem that includes Yellowstone and Grand Teton National Parks, according to a study by the Wildlife Conservation Society (WCS) and National Park Service. No, it's not the bison, the grizzly bear, or even the wolf, but the pronghorn antelope, which travels more than 400 miles between fawning grounds and wintering areas. Second only to caribou in the Arctic for long distance migration in the Western Hemisphere, this isolated population and its ancient migration route could disappear because of continued development and human disturbance outside the parks according to the study, which appears in the latest issue of the journal Biology Letters.

The study says that pronghorn have used the existing migration route in and out of the Yellowstone ecosystem for at least 6,000 years. Animals travel up to 30 miles a day, clambering over 8,500-foot mountain passes, and moving through bottlenecks now barely wider than a football field due to recent residential development. Increased petroleum extraction could further impact the migration route. Six of eight antelope migration corridors in and out of the Yellowstone ecosystem have already been lost.

"It's amazing that this marathon migration persists in a nation of almost 300 million people," said WCS researcher Joel Berger, the study's lead author. "At the same time, the migration is in real trouble, and needs immediate recognition and protection".........

Posted by: Tyler      Permalink         Source

July 11, 2006, 6:52 AM CT

Environmental Impacts Of Corn Ethanol And Biodiesel

The first comprehensive analysis of the full life cycles of soybean biodiesel and corn grain ethanol shows that biodiesel has much less of an impact on the environment and a much higher net energy benefit than corn ethanol, but that neither can do much to meet U.S. energy demand.

The study would be reported in the July 11 Proceedings of the National Academy of Sciences.

The scientists tracked all the energy used for growing corn and soybeans and converting the crops into biofuels. They also looked at how much fertilizer and pesticide corn and soybeans mandatory and how much greenhouse gases and nitrogen, phosphorus, and pesticide pollutants each released into the environment.

"Quantifying the benefits and costs of biofuels throughout their life cycles allows us not only to make sound choices today but also to identify better biofuels for the future," said Jason Hill, a postdoctoral researcher in the department of ecology, evolution, and behavior and the department of applied economics and lead author of the study.

The study showed that both corn grain ethanol and soybean biodiesel produce more energy than is needed to grow the crops and convert them into biofuels. This finding refutes other studies claiming that these biofuels require more energy to produce than they provide. The amount of energy each returns differs greatly, however. Soybean biodiesel returns 93 percent more energy than is used to produce it, while corn grain ethanol currently provides only 25 percent more energy.........

Posted by: Tyler      Permalink         Source

July 9, 2006, 8:05 PM CT

Large Forest Fires Linked To Climate Change

Large forest fires have occurred more frequently in the western United States since the mid-1980s as spring temperatures increased, mountain snows melted earlier and summers got hotter, as per new research.

Almost seven times more forested federal land burned during the 1987-2003 period than during the prior 17 years. In addition, large fires occurred about four times more often during the latter period.

The research is the most systematic analysis to date of recent changes in forest fire activity in the western United States. The increases in fire extent and frequency are strongly linked to higher March-through-August temperatures and are most pronounced for mid-elevation forests in the northern Rocky Mountains.

The new finding points to climate change, not fire suppression policies and forest fuel accumulation, as the primary driver of recent increases in large forest fires.

"I see this as one of the first big indicators of climate change impacts in the continental United States," said research team member Thomas W. Swetnam, director of the Laboratory of Tree-Ring Research at The University of Arizona in Tucson.

"We're showing warming and earlier springs tying in with large forest fire frequencies. Lots of people think climate change and the ecological responses are 50 to 100 years away. But it's not 50 to 100 years away -- it's happening now in forest ecosystems through fire."........

Posted by: Tyler      Permalink         Source

July 7, 2006, 9:27 PM CT

Western U.S. Wildfires

A new study led by researchers at Scripps Institution of Oceanography at the University of California, San Diego, implicates rising seasonal temperatures and the earlier arrival of spring conditions in connection with a dramatic increase of large wildfires in the western United States.

In the most systematic analysis to date of recent changes in forest fire activity, Anthony Westerling, Hugo Hidalgo and Dan Cayan of Scripps Oceanography, along with Tom Swetnam of the University of Arizona, compiled a database of recent large western wildfires since 1970 and compared it with climate and land-surface data from the region. The results show that large wildfire activity increased "suddenly and dramatically" in the 1980s with longer wildfire seasons and an increased number and more potent wildfires.

The new findings, reported in the July 6 issue of Science Express (the advance online version of the printed journal Science), point to climate change, not fire suppression policies and forest accumulation, as the primary driver of recent increases in large forest fires.

"The increase in large wildfires appears to be another part of a chain of reactions to climate warming," said Cayan, a coauthor of the paper and director of Scripps' Climate Research Division. "The recent ramp-up is likely, in part, caused by natural fluctuations, but evidence is mounting that anthropogenic effects have been contributing to warmer winters and springs in recent decades".........

Posted by: Tyler      Permalink         Source

July 4, 2006, 9:32 AM CT

Earth Observation Satellites And Polar Year 2007-2008

Thousands of researchers from 60 countries will be conducting research during International Polar Year 2007-2008 and will, for the first time during an International Polar Year, be armed with satellite measurements offering complete coverage of the polar regions, which play a vital role in the Earth's climate and ecosystems.

Having access to near-continuous satellite data of these regions over long periods of time is important for researchers to identify and analyse long-term climatic trends and changes. ESA will provide current and historical data, dating back 15 years, from its ERS-1, ERS-2 and Envisat satellites as well as data collected from many non-ESA satellites.

Dr. David Carlson, Director of the International Programme Office for the Polar Year, predicts a number of uses of satellite data: "A number of scientists use satellite data as part of their daily activities. During IPY those scientists will push to extract more and more information from the satellites, especially to understand recent and current distributions of snow and ice. We will use every form of satellite data - passive visual, active microwave, and even sensitive gravity measurements - to understand changes in the global ice sheets".

Since their advent satellites have contributed to a greater understanding of polar regions, helped identify the strong links these regions have with Earth's terrestrial, ocean and atmospheric processes and made startling observations. For example, within days of its launch in 2002, ESA's environmental satellite Envisat captured the disintegration of the Larsen-B ice shelf in Antarctica, surprising researchers because of the rapid rate at which the shelf broke apart.........

Posted by: Brooke      Permalink         Source

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