September 14, 2006, 4:30 AM CT
Warming climate might affect polar bear population
Some travel agencies touting Arctic tours have been revving up their recent promotions to tourists about the increased likelihood they will spot polar bears in this region where several populations of polar bears live. As per researchers from NASA and the Canadian Wildlife Service, these increased Arctic polar bear sightings are probably correlation to retreating sea ice triggered by climate warming and not due to population increases as some may believe.
The new research suggests that progressively earlier breakup of the Arctic sea ice, stimulated by climate warming, shortens the spring hunting season for female polar bears in Western Hudson Bay and is likely responsible for the continuing fall in the average weight of these bears. As females become lighter, their ability to reproduce and the survival of their young decline. Also, as the bears become thinner, they are more likely to push into human settlements for food, giving the impression that the population is increasing. The study will be published this week in the recent issue of the Journal Arctic.
Claire Parkinson, a scientist at NASA's Goddard Space Flight Center, Greenbelt, Md., and Ian Stirling, a senior scientist with the Canadian Wildlife Service, Edmonton, Alberta, used NASA satellite observations captured from 1979 to 2004 to show the reduction in sea ice cover in several specific areas where there are known polar bear populations. In most of the areas studied, they observed that ice break-up in these areas has been occurring progressively earlier.........
Posted by: Tyler Permalink Source
September 13, 2006, 9:51 PM CT
Arctic Sea Ice Diminishing Rapidly
The Arctic Ocean's perennial sea ice, which survives the summer melt season and remains year-round, shrank abruptly by 14 percent between 2004 and 2005, as per a newly published study. Scientists observed that the loss of perennial ice in the East Arctic Ocean, above Europe and Asia, neared 50 percent during that time as some of the ice moved to the West Arctic Ocean, above North America.
The overall decrease in winter Arctic perennial sea ice totaled 730,000 square kilometers [280,000 square miles]--an area the size of Texas. Perennial ice can be three meters [10 feet] thick, or more. It was replaced in the winter by new, seasonal ice, which was only about 0.3 to two meters [one to seven feet] thick and more vulnerable to summer melt. The research was published 7 September in the journal Geophysical Research Letters.
The decrease in perennial ice raises the possibility that Arctic sea ice will retreat to another record low extent this year. This follows four summers of very low ice-cover, as observed by active and passive microwave instruments.
A team of seven scientists, led by Son Nghiem of NASA's Jet Propulsion Laboratory in Pasadena, California, used satellite data to measure the extent and distribution of perennial and seasonal sea ice in the Arctic. While the total area of all Arctic sea ice was stable in winter, the distribution of seasonal and perennial sea ice changed significantly.........
Posted by: Tyler Permalink Source
September 13, 2006, 9:14 PM CT
Expedition to polar research
What better way to engage students in science than to apply lessons learned from fieldwork? This is the philosophy of Alaska teachers participating in the Arctic Expedition for K-12 Teachers, a program organized by the International Arctic Research Center (IARC) at the University of Alaska Fairbanks and a handful of international agencies.
For 33 days teachers from Alaska, Canada, France, Gera number of, Russia, Sweden and England will take atmospheric measurements, collect ice cores, install ice mass balance sensors and more, all under the guidance of an international team of polar researchers. Teachers and researchers will work together to collect data. Their work is based on the Kapitan Dranitsyn, an icebreaker currently cruising through the Arctic Ocean.
Todd Hindman, a teacher from Nome City School District, said This will give my students an opportunity to learn about the environment they live in, which will engage them in a meaningful way both inside and outside of the traditional classroom walls.
The experience will enhance my teaching by increasing my understanding of ocean systems, said Katie Turner, a science teacher at West Anchorage High School. It will give me real world experience and knowledge to share with my students.
The expedition advances researchers work in the fields of meteorology, biology, chemistry and oceanography. Five IARC researchers are aboard the Kapitan Dranitsyn, too, as part of the Nansen and Amundsen Basins Observational System (NABOS). Their aim is to better understand a flow of anomalous warm Atlantic water entering the Arctic Ocean. Preliminary data suggests this infusion of water from the Atlantic is increasing the temperature of the Arctic waters.........
Posted by: Tyler Permalink Source
September 11, 2006, 8:21 PM CT
Mysteries Of Kilimanjaro
Kilimanjaro in Tanzania is Africa's highest mountain, and eventhough it has been studied scientifically for over 100 years, it still hides some mysteries. Andreas Hemp has conducted extensive research on Kilimanjaro and reveals some of the mountain's secrets in an article published recently in the African Journal of Ecology.
The forests of Kilimanjaro are unusual for two reasons. One is that there is no bamboo zone, unlike the other East African mountains which have extensive bamboo forests. Another is that it was thought that there were only a few rare plants in the Kilimanjaro forests. Research by Hemp has explained the missing bamboo and uncovered a host of rare plants.
The missing bamboo is caused by a lack of elephants. Elephants are needed to create disturbance which encourages bamboo regeneration. However, on Kilimanjaro the lower slopes of the mountain are covered in cultivation preventing elephants from ascending into the forest "There are elephants on the dry side of the mountain" says Hemp "but the valleys are too steep and deep for elephants to traverse to the wet side where the bamboo could grow". The research demonstrates the complex links between plants and animals and the far reaching effects of changes caused by humans.
The rare plants were found in forest relicts in the deepest valleys of the cultivated lower areas suggesting that a rich forest flora once covered Mt. Kilimanjaro. The plants included a forest tree 40 m high that was new to science. "Kilimanjaro has long been excluded from the tropical rainforest biodiversity hotspot of Tanzania, but these exciting finds change the whole way we think about forest diversity of eastern Africa" said Jon Lovett, an expert in African biodiversity at the University of York.........
Posted by: Tyler Permalink Source
September 9, 2006, 7:53 AM CT
Ground movement risks identified
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Ground movements are responsible for hundreds of deaths and billions of Euros annually, and the threat they pose is increasing due to urbanisation and land use. ESA's GMES Service Element Programme is backing a project, Terrafirma, to help mitigate these risks.
To address these issues, Terrafirma is providing a Pan-European ground motion hazard information service to detect and monitor ground movements in relation to building stability, subsidence and ground heave, landslides, seismic activity and engineered excavations.
For over 15 years, Synthetic Aperture Radar Interferometry (InSAR) has been providing ground deformation data at centimetre precision. In the past five years, however, new ways of processing satellite radar images have been developed using Persistent Scatterer Interferometry (PSI) that allow ground movements over wide areas to be detected and monitored with even greater sensitivity.
Recent statistics show that 50% of the world population already live in cities, and megacities (over 10 million) are now commonplace. As the trend toward urbanisation continues, most major towns will undergo construction to accommodate new developments for newcomers.
New construction requires solid foundations to avoid costly planning mistakes, and underground works and metro-tunnelling have some surface effect that needs remediation and monitoring. The Terrafirma services can provide information to locate low-risk foundation sites and help save money on the remediation of existing structures.........
Posted by: Tyler Permalink Source
September 7, 2006, 8:20 PM CT
Siberian lakes and greenhouse gas
Frozen bubbles in Siberian lakes are releasing methane, a greenhouse gas, at rates that appear to be ". five times higher than previously estimated" and acting as a positive feedback to climate warming, said Katey Walter, in a paper published recently in the journal Nature.
Walter's project is the first time this type of bubbling has been accurately quantified. "We realized that our prior estimates were missing a very large and important component of lake emissions - in these bubbles were the dominant source of methane from lakes," said Walter, an International Polar Year post-doctoral fellow at the Institute of Arctic Biology at the University of Alaska Fairbanks.
As per Walter, her team's calculations increase the present estimate of methane emissions from northern wetlands by between 10 and 63 percent.
Water studied a unique type of permafrost in Siberia, called yedoma, which contains an estimated 500 gigatons of carbon, largely in the form of ancient dead plant material. "This material has been locked up in permafrost since the end of the last ice age," Walter said. "Now it is being released into the bottom of lakes, providing microbes a banquet from which they burp out methane as a byproduct of decomposition."
"Permafrost models predict significant thaw of permafrost during this century, which means that yedoma permafrost is like a time bomb waiting to go off - as it continues to thaw, tens of thousands of teragrams of methane can be released to the atmosphere enhancing climate warming," Walters said. "This newly recognized source of methane is so far not included in climate models".........
Posted by: Tyler Permalink Source
September 6, 2006, 7:46 PM CT
Greenhouse gas bubbling
Methane bubbles trapped in lake ice
Credit: Courtesy of Jeff Chanton, FSU Oceanography Departmen
A co-author of studyed by a Florida State University scientist and reported in the Sept. 7 issue of the journal Nature has observed that as the permafrost melts in North Siberia due to climate change, carbon sequestered and buried there since the Pleistocene era is bubbling up to the surface of Siberian thaw lakes and into the atmosphere as methane, a greenhouse gas 20 times more potent than carbon dioxide.
In turn, that bubbling methane held captive as carbon under the permafrost for more than 40,000 years is accelerating global warming by heating the Earth even more --- exacerbating the entire cycle. The ominous implications of the process grow as the permafrost decomposes further and the resulting lakes continue to expand, as per FSU oceanography Professor Jeff Chanton and co-author of studys at the University of Alaska-Fairbanks.
"This is not good for the quality of human life on Earth," Chanton said.
The scientists devised a novel method of measuring ebullition (bubbling) to more accurately quantify the methane emissions from two Siberian thaw lakes and in so doing, revealed the world's northern wetlands as a much larger source of methane release into the atmosphere than previously believed. The magnitude of their findings has increased estimates of such emissions by 10 to 63 percent.........
Posted by: Tyler Permalink Source
September 6, 2006, 5:01 AM CT
World fruit flies on three continents
Old World fruit fly, Drosophila subobscura superimposed over chromosomes from the species.
Fast-warming climate appears to be triggering genetic changes in a species of fruit fly that is native to Europe and was introduced into North and South America about 25 years ago.
"This is a clear signal on three different continents that climate change is occurring, and that genetic change is going along with it," said Raymond Huey, a University of Washington biology professor who is co-author of a paper describing the findings, published Aug. 31 in Science Express, the online edition of the journal Science.
The research deals with an Old World fruit fly species called Drosophila subobscura, which originally ranged from the Mediterranean Sea to Scandinavia. European biologists who studied the insect's genetic makeup more than 40 years ago noted that sections of chromosomes were inverted, something like taking part of a bar code from a consumer product and flipping it backwards. The biologists found that the frequency of particular inversions was correlated with the latitude where a given insect was found. Inversions that were common in the north were uncommon in the south, and vice versa.
The fruit flies were accidentally introduced to the Pacific Coast of Chile in the late 1970s and to the North American West Coast in the early 1980s, probably on cargo ships. They spread rapidly, and in North America they are now found from near Santa Barbara, Calif., to northern Vancouver Island in British Columbia.........
Posted by: Ashley Permalink Source
September 6, 2006, 4:55 AM CT
Antarctica has warmed in last 150 years
Despite recent indications that Antarctica cooled considerably during the 1990s, new research suggests that the world's iciest continent has been getting gradually warmer for the last 150 years, a trend not identifiable in the short meteorological records and masked at the end of the 20th century by large temperature variations.
Numerous ice cores collected from five areas allowed researchers to reconstruct a temperature record that shows average Antarctic temperatures have risen about two-tenths of a degree Celsius, or about one-third of a degree Fahrenheit, in 150 years. That might not sound like much, but the overall increase includes a recorded temperature decline of nearly 1 degree in the 1990s, said David Schneider, a University of Washington postdoctoral researcher in Earth and space sciences.
"Even if you account for the cooling in the '90s, we still see that two-tenths of a degree increase from the middle of the 1800s to the end of the 20th century," said Schneider, the lead author of a paper detailing the work published Aug. 30 in Geophysical Research Letters.
The main reason that Antarctica appears to have cooled during the 1990s is that a natural phenomenon called the Antarctic Oscillation, or Southern Annular Mode, was largely in its positive phase during that time. The Antarctic Oscillation is so named because atmospheric pressure in far southern latitudes randomly oscillates between positive and negative phases. During the positive phase, a vortex of wind is tightly focused on the polar region and prevents warmer air from mixing with the frigid polar air, which keeps Antarctica colder.........
Posted by: Tyler Permalink Source
September 5, 2006, 9:13 PM CT
Life Beyond Carbon
Photo / Donna Coveney
John Heywoo
If all nations burned gasoline for transportation at the same rate as the United States, world gasoline consumption would rise nearly ten-fold, with a corresponding hike in the concentration of greenhouse gases.
That's just one reason why it is imperative that nations work to create a more sustainable transportation system, says John Heywood, director of MIT's Sloan Automotive Lab and the Sun Jae Professor of Mechanical Engineering.
"As the countries in the developing world rapidly motorize, the increasing global demand for fuel will pose one of the biggest challenges to controlling the concentration of greenhouse gases in the atmosphere," Heywood writes in "Fueling Our Transportation Future," an article he wrote for the recent issue of Scientific American.
Heywood is one of three MIT professors who tackle energy in the magazine's September issue, whose cover proclaims the theme "Energy's Future: Beyond Carbon".
While Heywood's article focuses on improving transportation efficiency, MIT Professors John Deutch and Ernest Moniz explore the possibilities of expanding nuclear power to reduce emissions of greenhouse gases.
All three professors are members of MIT's Energy Research Council, which issued a report in May exploring how MIT can help solve the global energy crisis.........
Posted by: Sarah Permalink Source
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