*Computer simulations of global climate lead to new conclusions*
Earth’s deep oceans may absorb enough heat at times to flatten the rate of global warming for periods of as long as a decade–even in the midst of longer-term warming. This according to a new analysis led by scientists at the National Center for Atmospheric Research (NCAR).
The study, based on computer simulations of global climate, points to ocean layers deeper than 1,000 feet as the main location of the “missing heat” during periods such as the past decade when global air temperatures showed little trend. (more…)
Washington, DC — Scientists have long debated about the impact on global climate of water evaporated from vegetation. New research from Carnegie’s Global Ecology department concludes that evaporated water helps cool the earth as a whole, not just the local area of evaporation, demonstrating that evaporation of water from trees and lakes could have a cooling effect on the entire atmosphere. These findings, published September 14 in Environmental Research Letters, have major implications for land-use decision making.
Evaporative cooling is the process by which a local area is cooled by the energy used in the evaporation process, energy that would have otherwise heated the area’s surface. It is well known that the paving over of urban areas and the clearing of forests can contribute to local warming by decreasing local evaporative cooling, but it was not understood whether this decreased evaporation would also contribute to global warming (more…)
*Research at Greenland and Antarctic shows decline in methane and ethane levels*
Recent data from NSF-funded research in both Greenland and Antarctica demonstrate that fossil-fuel related emissions of both methane and ethane, two of the most abundant hydrocarbons in the atmosphere, declined at the end of the twentieth century, according to a paper published Thursday in the journal Nature.
The causes of the decline in methane emission rates to the atmosphere have been puzzling scientists for some time. This new study shows that a change in human activities may have played a key role in the recent leveling off of methane, which, being a potent greenhouse gas contributes to global temperatures. (more…)
The 2011 Arctic sea ice extent maximum that marks the beginning of the melt season appears to be tied for the lowest ever measured by satellites, say scientists at the University of Colorado Boulder’s National Snow and Ice Data Center.
The CU-Boulder research team believes the lowest annual maximum ice extent of 5,650,000 square miles occurred on March 7. The maximum ice extent was 463,000 square miles below the 1979-2000 average, an area slightly larger than the states of Texas and California combined. The 2011 measurements were tied with those from 2006 as the lowest maximum sea ice extents measured since satellite record keeping began in 1979. (more…)
AUSTIN, Texas — Global warming is clearly affecting plants and animals, but we should not try to tease apart the specific contribution of greenhouse gas driven climate change to extinctions or declines of species at local scales, biologists from The University of Texas at Austin advise.
“Yes, global warming is happening. Yes, it is caused by human activities. And yes, we’ve clearly shown that species are impacted by global warming on a global scale,” says Parmesan, associate professor of integrative biology. (more…)
Since the 1970s, hydrogen has been touted as a promising alternative to fossil fuels due to its clean combustion —unlike the combustion of fossil fuels, which spews greenhouse gases and harmful pollutants, hydrogen’s only combustion by-product is water. Compared to gasoline, hydrogen is lightweight, can provide a higher energy density and is readily available. But there’s a reason we’re not already living in a hydrogen economy: to replace gasoline as a fuel, hydrogen must be safely and densely stored, yet easily accessed. Limited by materials unable to leap these conflicting hurdles, hydrogen storage technology has lagged behind other clean energy candidates. (more…)
*Waterways receiving nitrogen from human activities are significant source*
What goes in must come out, a truism that now may be applied to global river networks.
Human-caused nitrogen loading to river networks is a potentially important source of nitrous oxide emission to the atmosphere. Nitrous oxide is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. (more…)
ANCHORAGE, Alaska – Sea-ice habitats essential to polar bears would likely respond positively should more curbs be placed on global greenhouse gas emissions, according to a new modeling study published in the journal, Nature.
The study, led by the U.S. Geological Survey, included university and other federal agency scientists. The research broke new ground in the “tipping point” debate in the scientific community by providing evidence that during this century there does not seem to be a tipping point at which sea-ice loss would become irreversible. (more…)
