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Water Evaporated from Trees Cools Global Climate

By Guest PostSeptember 17, 2011Environmentatmosphere, central park, earth, emissions of carbon dioxide, evaporated water, evaporation, george ban-weiss, global balance of energy, global climate, global warming, govindasamy bala, greenhouse gas, julia pongratz, ken caldeira, new york, vegetation, water, water vapor

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…)

UF Study Shows Tundra Fires Could Accelerate Climate Warming

By Guest PostJuly 31, 2011Environmentanaktuvuk river fire, arctic carbon cycle, arctic fires, arctic tundra, atmosphere, atmospheric carbon dioxide, canada, carbon, city of miami, ecologist, ecosystem ecology, global climate, global climate warming, greenhouse gases, michelle mack, Nature, north slope of alaska brooks range, organic matter, permafrost, radiocarbon dating, russia, smoke, soil bound carbon, ted schuur, terry chapin, tundra, university of alaska, university of florida, wildfires

GAINESVILLE, Fla. — After a 10,000-year absence, wildfires have returned to the Arctic tundra, and a University of Florida study shows that their impact could extend far beyond the areas blackened by flames.

In a study published in the July 28 issue of the journal Nature, UF ecologist Michelle Mack and a team of scientists including fellow UF ecologist Ted Schuur quantified the amount of soil-bound carbon released into the atmosphere in the 2007 Anaktuvuk River fire, which covered more than 400 square miles on the North Slope of Alaska’s Brooks Range. The 2.1 million metric tons of carbon released in the fire — roughly twice the amount of greenhouse gases put out by the city of Miami in a year — is significant enough to suggest that Arctic fires could impact the global climate, said Mack, an associate professor of ecosystem ecology in UF’s department of biology. (more…)

Significant Role of Oceans in Onset of Ancient Global Cooling

By Guest PostMay 28, 2011Environmentacc, american midwest, antarctic circumpolar current, antarctic intermediate water, benjamin cramer, benthic foraminifera, bridget wade, candace major, chengjie liu, deep sea drilling project, early cenozoic, environmental conditions, fossil skeletons, glaciations, global climate, global cooling pattern, global ocean circulation, global temperatures, greenhouse climate, icehouse, integrated ocean drilling program, isotopes, late eocene, marsupials, miriam katz, mixmaster of the ocean, ocean drilling program, ocean sediments, oceans, planktonic organisms, polar regions, sea floor, tropical jungles

*Evidence that early Antarctic Circumpolar Current development affected global climate*

Thirty-eight million years ago, tropical jungles thrived in what are now the cornfields of the American Midwest and furry marsupials wandered temperate forests in what is now the frozen Antarctic.

The temperature differences of that era, known as the late Eocene, between the equator and Antarctica were half what they are today. (more…)

Threading the Climate Needle: The Agulhas Current System

By Guest PostApril 28, 20111 commentEnvironmentagulhas current, agulhas retroflection, amoc, atlantic, atlantic meridional overturning circulation, atlantic ocean, climate change, climate modeling, east coast of africa, glacial cycles, global climate, gulf stream, indian ocean, lisa beal, national science foundation, northern hemisphere, paleoceanographic data

*Increased Agulhas “leakage” significant player in global climate variability*

The Agulhas Current which runs along the east coast of Africa may not be as well known as its counterpart in the Atlantic, the Gulf Stream. But now researchers are taking a closer look at this current and its “leakage” from the Indian Ocean into the Atlantic Ocean–and what that may mean for climate change.

In results of a study published in this week’s issue of the journal Nature, a team of scientists led by University of Miami Rosenstiel School of Marine & Atmospheric Science Oceanographer Lisa Beal, suggests that Agulhas leakage could be a significant player in global climate variability. (more…)

Corals Show Ocean Temperature Boundary Rising with Climate Change

By Guest PostOctober 14, 20101 commentEnvironment, Natureandrea grottoli, branwen williams, climate modelers, computer models, coral reef, corals, el niño, global climate, global warming, gorgonian, isotopes, nitrogen 14, nitrogen 15, ocean circulation, oceanography, offshore, ohio state university, pacific decadal oscillation, palau, pdo, satellite data, thermocline, western tropical pacific

WASHINGTON — Researchers looking at corals in the western tropical Pacific Ocean have found signs of a profound shift in the depth where warm surface water and colder deeper water meet—a shift predicted by computer models of global warming.

The finding is the first physical evidence supporting what climate modelers have been predicting as the effects of global climate change on the subsurface ocean circulation. (more…)

‘Sea Levels Rising in Parts of Indian Ocean’

By Guest PostJuly 15, 20102 commentsEnvironmentafrica, Antarctica, arabian sea, atmospheric, balaji rajagopalan, Bangladesh, bay of bengal, global climate, greenhouse gases, India, indian ocean, indo-pacific, Java, mascarenhas archipelago, naval research laboratory in Mississippi, ncar, sea levels, seychelles Islands, sri lanka, sumatra, Tanzania, university of colorado at boulder, weiqing han, Zanzibar

*Greenhouse gases are playing a role in changes, say scientists*

Newly detected rising sea levels in parts of the Indian Ocean, including the coastlines of the Bay of Bengal, the Arabian Sea, Sri Lanka, Sumatra and Java, appear to be at least partly a result of human-induced increases of atmospheric greenhouse gases, says a study led by the University of Colorado at Boulder.

(more…)

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