A new study reports that charcoal particles left by wildfires in sediments of 35 North American lake beds don't readily support the theory that comets exploding over the continent 12,900 years ago sparked a cooling period known as the Younger Dryas.
Earth
Taking up valuable land and growing edible crops for biofuels poses a dilemma: Is it ethical to produce inefficient renewable energies at the expense of an already malnourished population? David Pimentel and his colleagues from Cornell University in New York highlight the problems linked to converting a variety of crops into biofuels. Not only are these renewable energies inefficient, they are also economically and environmentally costly and nowhere near as productive as projected. Their findings (1) are published online this week in Springer's journal Human Ecology.
The first comprehensive assessment of the climate cooling potential of different geoengineering schemes has been carried out by researchers at the University of East Anglia (UEA).
Funded by the Natural Environment Research Council and published today in the journal 'Atmospheric Chemistry and Physics Discussions', the key findings include:
Princeton, NJ – January 27, 2009 – A new study by researchers at Princeton University's Woodrow Wilson School of Public and International Affairs has found that global climate change may lead to the retreat of some invasive plant species in the western United States, which could create unprecedented ecological restoration opportunities across millions of acres throughout America. At the same time, global warming may enable other invasive plants to spread more widely.
New data, published today, disproves the recent theory that a large comet exploded over North America 12,900 years ago, causing a shock wave that travelled across North America at hundreds of kilometres per hour and triggering continent-wide wildfires.
Dr Sandy Harrison from the University of Bristol and colleagues tested the theory by examining charcoal and pollen records to assess how fire regimes in North America changed between 15 and 10,000 years ago, a time of large and rapid climate changes.
Bayreuth/Leipzig. More frequent freeze-thaw cycles in winter can increase biomass production according to the results of a recent study conducted by the Helmholtz Center for Environmental Research (UFZ), the University of Bayreuth and the Helmholtz Center in Munich. For their experiment at the Ecological-Botanical Garden of the University of Bayreuth the researchers installed underground heating on their plots, thereby enabling five additional thawing periods to take place in the winter of 2005/2006.
Unchecked global warming would leave ocean dwellers gasping for breath. Dead zones are low-oxygen areas in the ocean where higher life forms such as fish, crabs and clams are not able to live. In shallow coastal regions, these zones can be caused by runoff of excess fertilizers from farming. A team of Danish researchers have now shown that unchecked global warming would lead to a dramatic expansion of low-oxygen areas zones in the global ocean by a factor of 10 or more.
HILO, Hawaii January 23, 2009—New technology deployed on airplanes is helping scientists quantify landscape-scale changes occurring to Big Island tropical forests from non-native plants and other environmental factors that affect carbon sequestration.
U.S. Forest Service and Carnegie Institution scientists involved in the research published their findings this month in the journal Ecosystems and hope it will help other researchers racing to assess threats to tropical forests around the world.
(Flagstaff, Ariz.- Jan. 23, 2009) - Global warming is speeding up the mortality of trees, and Northern Arizona University research is providing some of the data to prove it.
Pete Fulé, an NAU associate professor in the School of Forestry and a director of the university's Ecological Restoration Institute, is a coauthor of "Widespread Increase of Tree Mortality Rates in the Western United States," an article to be published in the Jan. 23 issue of Science journal.
Did a catastrophic flood of biblical proportions drown the shores of the Black Sea 9,500 years ago, wiping out early Neolithic settlements around its perimeter? A geologist with the Woods Hole Oceanographic Institution (WHOI) and two Romanian colleagues report in the January issue of Quaternary Science Reviews that, if the flood occurred at all, it was much smaller than previously proposed by other researchers.
Trees are dying twice as fast as they did three decades ago in older forests of the western United States and scientists suspect warming temperatures are a contributing factor.
CORVALLIS, Ore. – Regional warming and drought stress are the "dominant contributors" to a rapid increase of tree mortality in old growth forests across the West during the past 50 years, a new report concludes, with the Pacific Northwest the hardest hit of all areas studied.
The findings, to be published Friday in the journal Science, suggest that a persistent increase in the mortality rate would ultimately cause a 50 percent reduction in the average tree age in forests, a potential reduction in average tree size and make many forests vulnerable to abrupt dieback.
Tree death rates have more than doubled over the last few decades in old-growth forests of the western United States, and the most probable cause of the worrisome trend is regional warming, according to a U.S. Geological Survey-led (USGS) study published in Science on January 23.
The study found that the increase in dying trees has been pervasive. Tree death rates have increased across a wide variety of forest types, at all elevations, in trees of all sizes, and in pines, firs, hemlocks, and other kinds of trees.
A new study led by the U.S. Geological Survey and involving the University of Colorado at Boulder indicates tree deaths in the West's old-growth forests have more than doubled in recent decades, likely from regional warming and related drought conditions.
Scientists at Penn State University and the Virginia Commonwealth University have discovered a way to produce hydrogen by exposing selected clusters of aluminum atoms to water. The findings are important because they demonstrate that it is the geometries of these aluminum clusters, rather than solely their electronic properties, that govern the proximity of the clusters' exposed active sites. The proximity of the clusters' exposed sites plays an important role in affecting the clusters' reactions with water.