March 25, 2008, 8:10 PM CT

Antarctic ice shelf disintegrating

Satellite imagery from the University of Colorado at Boulder's National Snow and Ice Data Center shows a portion of Antarctica's massive Wilkins Ice Shelf has begun to collapse because of rapid climate change in a fast-warming region of the continent.

While the area of collapse involves 160 square miles at present, a large part of the 5,000-square-mile Wilkins Ice Shelf is now supported only by a narrow strip of ice between two islands, said CU-Boulder's Ted Scambos, lead scientist at NSIDC. "If there is a little bit more retreat, this last 'ice buttress' could collapse and we'd likely lose about half the total ice shelf area in the next few years".

In the past 50 years, the western Antarctic Peninsula has experienced the biggest temperature increase on Earth, rising by 0.9 degree F per decade. "We believe the Wilkins has been in place for at least a few hundred years, but warm air and exposure to ocean waves are causing a breakup," said Scambos, who first spotted the disintegration activity in March.

Satellite images indicate the Wilkins began its collapse on Feb. 28. Data revealed that a large iceberg, measuring 25.5 by 1.5 miles, fell away from the ice shelf's southwestern front, triggering a runaway disintegration of 220 square miles of the shelf interior. The Wilkins Ice Shelf is a broad sheet of permanent floating ice on the southwest Antarctic Peninsula roughly 1,000 miles south of South America......... Posted by: Tyler      Read more         Source

March 24, 2008, 8:32 PM CT

New findings from Tibetan Plateau suggest uplift occurred in stages

The vast Tibetan Plateau--the world's highest and largest plateau, bordered by the world's highest mountains--has long challenged geologists trying to understand how and when the region rose to such spectacular heights. New evidence from an eight-year study by U.S. and Chinese scientists indicates that the plateau rose in stages, with uplift occurring first in the central plateau and later in regions to the north and south.

"The middle part of the plateau was uplifted first at least 40 million years ago, while the Himalayan Range in the south and also the mountains to the north were uplifted significantly later," said Xixi Zhao, a research scientist at the University of California, Santa Cruz.

The team found marine fossils suggesting that the now lofty Himalayas remained below sea level at a time when the central plateau was already at or near its modern elevation, Zhao said. The average elevation of the plateau today is more than 4,500 meters (14,850 feet).

The scientists published their findings in the Proceedings of the National Academy of Sciences (online the week of March 24 and later in print). Zhao, who is affiliated with the Institute of Geophysics and Planetary Physics at UCSC, is the second author of the paper. First author Chengshan Wang of the China University of Geosciences in Beijing has been collaborating with Zhao and other UCSC scientists since 1996......... Posted by: Tyler      Read more         Source

March 18, 2008, 8:47 PM CT

Elevated CO2 From Manmade Emissions

Using data from the SCIAMACHY instrument aboard ESA's Envisat environmental satellite, researchers have for the first time detected regionally elevated atmospheric carbon dioxide - the most important greenhouse gas that contributes to global warming - originating from manmade emissions.

More than 30 billion tonnes of extra carbon dioxide (CO2) is released into the atmosphere annually by human activities, mainly through the burning of fossil fuels.

As per the latest report by the Intergovernmental Panel on Climate Change (IPCC), this increase is predicted to result in a warmer climate with rising sea levels and an increase of extreme weather conditions. Predicting future atmospheric CO2 levels requires an increase in our understanding of carbon fluxes.

Dr Michael Buchwitz from the Institute of Environmental Physics (IUP) at the University of Bremen in Gera number of and colleagues detected the relatively weak atmospheric CO2 signal arising from regional 'anthropogenic', or manmade, CO2 emissions over Europe by processing and analysing SCIAMACHY data from 2003 to 2005.

As illustrated in the image, the findings show an extended plume over Europe's most populated area, the region from Amsterdam in the Netherlands to Frankfurt, Gera number of......... Posted by: Tyler      Read more         Source

March 18, 2008, 8:23 PM CT

Arctic sea ice still at risk despite cold winter

Using the latest satellite observations, NASA scientists and others report that the Arctic is still on thin ice when it comes to the condition of sea ice cover in the region. A colder-than-average winter in some regions of the Arctic this year has yielded an increase in the area of new sea ice, while the older sea ice that lasts for several years has continued to decline.

On March 18 the researchers said they think that the increased area of sea ice this winter is due to recent weather conditions, while the decline in perennial ice reflects the longer-term warming climate trend and is a result of increased melting during summer and greater movement of the older ice out of the Arctic.

Perennial sea ice is the long-lived, year-round layer of ice that remains even when the surrounding short-lived seasonal sea ice melts away in summer to its minimum extent. It is this perennial sea ice, left over from the summer melt period, that has been rapidly declining from year to year, and that has gained the attention and research focus of scientists. As per NASA-processed microwave data, whereaccording toennial ice used to cover 50-60 percent of the Arctic, this year it covers less than 30 percent. Very old ice that remains in the Arctic for at least six years comprised over 20 percent of the Arctic area in the mid to late 1980s, but this winter it decreased to just six percent......... Posted by: Tyler      Read more         Source

March 11, 2008, 10:54 PM CT

Climate change and transportation

While every mode of transportation in the U.S. will be affected as the climate changes, potentially the greatest impact on transportation systems will be flooding of roads, railways, transit systems, and airport runways in coastal areas because of rising sea levels and surges brought on by more intense storms, says a new report from the National Research Council. Though the impacts of climate change will vary by region, it is certain they will be widespread and costly in human and economic terms, and will require significant changes in the planning, design, construction, operation, and maintenance of transportation systems.

The U.S. transportation system was designed and built for local weather and climate conditions, predicated on historical temperature and precipitation data. The report finds that climate predictions used by transportation planners and engineers may no longer be reliable, however, in the face of new weather and climate extremes. Infrastructure pushed beyond the range for which it was designed can become stressed and fail, as seen with loss of the U.S. 90 Bridge in New Orleans after Hurricane Katrina.

"The time has come for transportation professionals to acknowledge and confront the challenges posed by climate change, and to incorporate the most current scientific knowledge into the planning of transportation systems," said Henry Schwartz Jr., past president and chairman of Svedrup/Jacobs Civil Inc., and chair of the committee that wrote the report. "It is now possible to project climate changes for large subcontinental regions, such as the Eastern United States, a scale better suited for considering regional and local transportation infrastructure." ......... Posted by: Tyler      Read more         Source

March 11, 2008, 5:34 AM CT

China's Carbon Dioxide Emissions

The growth in China's carbon dioxide (CO2) emissions is far outpacing prior estimates, making the goal of stabilizing atmospheric greenhouse gases much more difficult, as per a new analysis by economists at the University of California, Berkeley, and UC San Diego.

Prior estimates, including those used by the Intergovernmental Panel on Climate Change, say the region that includes China will see a 2.5 to 5 percent annual increase in CO2 emissions, the largest contributor to atmospheric greenhouse gases, between 2004 and 2010. The new UC analysis puts that annual growth rate for China to at least 11 percent for the same time period.

The study is scheduled for print publication in the recent issue of the Journal of Environmental Economics and Management, but is now online.

The researchers' most conservative forecast predicts that by 2010, there will be an increase of 600 million metric tons of carbon emissions in China over the country's levels in 2000. This growth from China alone would dramatically overshadow the 116 million metric tons of carbon emissions reductions pledged by all the developed countries in the Kyoto Protocol. (The protocol was never ratified in the United States, which was the largest single emitter of carbon dioxide until 2006, when China took over that distinction, as per numerous reports.)......... Posted by: Tyler      Read more         Source

February 28, 2008, 10:30 PM CT

What caused westward expansion in the United States?

Western Expansion during the nineteenth century was an important determinant of geographic distribution and economic activity in the United States today. However, while explanations abound for why the migration occurred from the low price of land to a pioneering spirit little empirical work has been done to determine which specific market forces were the most important drivers.

Applying quantitative analysis to historical explanations, a new study by economist Guillaume Vandenbroucke of the University of Southern California finds that the price of land was significantly less important to Westward Expansion than population growth and technological innovation leading to a decrease in transportation costs.

From 1800 to 1900, the United States tripled in size, from less than one million square miles to more than three million square miles. The geographic distribution of population also shifted, from about seven percent living in the West to roughly 60 percent. To examine what forces were most directly responsible for the magnitude of this movement and land accumulation, Vandenbroucke takes into account such factors as the amount of land available in the Eastern United States, wage and productivity growth in the East, and improvements in technologies and transportation infrastructures......... Posted by: Tyler      Read more         Source

February 28, 2008, 9:42 PM CT

The rain-making bacteria

LSU professor of biological sciences, in partnership with colleagues in Montana and France, recently found evidence that rain-making bacteria are widely distributed in the atmosphere. These biological particles could factor heavily into the precipitation cycle, affecting climate, agricultural productivity and even global warming. Christner and colleagues will publish their results in the prestigious journal Science on Feb. 29.

Christners team examined precipitation from global locations and demonstrated that the most active ice nuclei a substrate that enhances the formation of ice are biological in origin. This is important because the formation of ice in clouds is mandatory for snow and most rainfall. Dust and soot particles can serve as ice nuclei, but biological ice nuclei are capable of catalyzing freezing at much warmer temperatures. If present in clouds, biological ice nuclei may affect the processes that trigger precipitation.

The concept of rain-making bacteria isnt far-fetched. Cloud seeding with silver iodide or dry ice has been done for more than 60 years. A number of ski resorts use a commercially available freeze-dried preparation of ice-nucleating bacteria to make snow when the temperature is just a few degrees below freezing.

My colleague David Sands from Montana State University proposed the concept of bioprecipitation over 25 years ago and few researchers took it seriously, but evidence is beginning to accumulate that supports this idea, said Christner......... Posted by: Tyler      Read more         Source

February 26, 2008, 10:15 PM CT

Destruction of Sumatra forests driving global climate

Turning just one Sumatran province's forests and peat swamps into pulpwood and palm oil plantations is generating more annual greenhouse gas emissions than the Netherlands and rapidly driving the province's elephants into extinction, a new study by WWF and partners has found.

The study observed that in central Sumatra's Riau Province nearly 10.5 million acres of tropical forests and peat swamp have been cleared in the last 25 years. Forest loss and degradation and peat decomposition and fires are behind average annual carbon emissions equivalent to 122 percent of the Netherlands total annual emissions, 58 percent of Australia's annual emissions, 39 percent of annual UK emissions and 26 percent of annual German emissions.

Riau was chosen for the study because it is home to vast peatlands estimated to hold Southeast Asias largest store of carbon, and contains some of the most critical habitat for Sumatran elephants and tigers. It also has Indonesia's highest deforestation rate, substantially driven by the operations of global paper giants Asia Pulp & Paper (APP) and Asia Pacific Resources International Holdings Limited (APRIL).

At last December's Bali Climate Change Conference, the Indonesian minister of Forestry pledged to provide incentives to stop unsustainable forestry practices and protect Indonesia's forests. The governor of Riau province has also made a public commitment to protect the province's remaining forest......... Posted by: Tyler      Read more         Source

February 26, 2008, 10:05 PM CT

Voyage to Southern Ocean

Researchers will embark this week from Punta Arenas, Chile, on the tip of South America, to spend 42 days amid the high winds and waves of the Southern Ocean. Here they hope to make groundbreaking measurements to explain how huge fluxes of climate-affecting gases move between atmosphere and sea, and vice-versa.

The cruise, which departs Feb. 28, should provide important information on how the greenhouse gas carbon dioxide moves between the ocean and atmosphere, said the cruises chief scientist, David Ho of Columbia Universitys Lamont-Doherty Earth Observatory. Comprising 30 percent of global seas, the Southern Ocean is a source of great uncertainty, he said. So its potentially important to our understanding of the global system.

Humans put about 6 billion metric tons of CO2 into the air each year, mainly by fossil-fuel burning and deforestation. About a third is believed to be absorbed by oceans, and a third by plants or other components of land. The rest stays in the airmuch of the reason why atmospheric CO2 is now building and climate is warming. However, there are huge uncertainties in the calculationsmade so far mostly through indirect means--and fluxes seem highly variable from year to year, with some parts of the oceans habitually giving up CO2 while others absorb it. (The Southern Ocean commonly absorbs it.) "Understanding how atmospheric carbon dioxide reacts with these cold surface waters is important for determining how the ocean uptake of carbon dioxide will respond to future climate change, said Christopher Sabine, an oceanographer at the U.S. National Oceanic and Atmospheric Administration (NOAA). NOAA, NASA and the National Science Foundation are cosponsoring the cruise......... Posted by: Tyler      Read more         Source