Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. 24/7 Space News .




ICE WORLD
Black Carbon Driving Himalayan Melt
by Staff Writers
San Francisco CA (SPX) Feb 08, 2010


This map of the change in annual linear snow cover from 1990 to 2001 shows a thick band (blue) across the Himalayas with decreases of at least 16 percent while a few smaller patches (red) saw increases. The data was collected by the National Snow and Ice Data Center.

The fact that glaciers in the Himalayan mountains are thinning is not disputed. However, few researchers have attempted to rigorously examine and quantify the causes. Lawrence Berkeley National Laboratory scientist Surabi Menon set out to isolate the impacts of the most commonly blamed culprit-greenhouse gases, such as carbon dioxide-from other particles in the air that may be causing the melting. Menon and her collaborators found that airborne black carbon aerosols, or soot, from India is a major contributor to the decline in snow and ice cover on the glaciers.

"Our simulations showed greenhouse gases alone are not nearly enough to be responsible for the snow melt," says Menon, a physicist and staff scientist in Berkeley Lab's Environmental Energy Technologies Division. "Most of the change in snow and ice cover-about 90 percent-is from aerosols. Black carbon alone contributes at least 30 percent of this sum."

Menon and her collaborators used two sets of aerosol inventories by Indian researchers to run their simulations; their results were published online in the journal Atmospheric Chemistry and Physics.

The actual contribution of black carbon, emitted largely as a result of burning fossil fuels and biomass, may be even higher than 30 percent because the inventories report less black carbon than what has been measured by observations at several stations in India. (However, these observations are too incomplete to be used in climate models.) "We may be underestimating the amount of black carbon by as much as a factor of four," she says.

The findings are significant because they point to a simple way to make a swift impact on the snow melt. "Carbon dioxide stays in the atmosphere for 100 years, but black carbon doesn't stay in the atmosphere for more than a few weeks, so the effects of controlling black carbon are much faster," Menon says. "If you control black carbon now, you're going to see an immediate effect."

The Himalayan glaciers are often referred to as the third polar ice cap because of the large amount of ice mass they hold. The glacial melt feeds rivers in China and throughout the Indian subcontinent and provide fresh water to more than one billion people.

Atmospheric aerosols are tiny particles containing nitrates, sulfates, carbon and other matter, and can influence the climate. Unlike other aerosols, black carbon absorbs sunlight, similar to greenhouse gases. But unlike greenhouse gases, black carbon does not heat up the surface; it warms only the atmosphere.

This warming is one of two ways in which black carbon melts snow and ice. The second effect results from the deposition of the black carbon on a white surface, which produces an albedo effect that accelerates melting. Put another way, dirty snow absorbs far more sunlight-and gets warmer faster-than pure white snow.

Previous studies have shown that black carbon can have a powerful effect on local atmospheric temperature. "Black carbon can be very strong," Menon says. "A small amount of black carbon tends to be more potent than the same mass of sulfate or other aerosols."

Black carbon, which is caused by incomplete combustion, is especially prevalent in India and China; satellite images clearly show that its levels there have climbed dramatically in the last few decades. The main reason for the increase is the accelerated economic activity in India and China over the last 20 years; top sources of black carbon include shipping, vehicle emissions, coal burning and inefficient stoves. According to Menon's data, black carbon emitted in India increased by 46 percent from 1990 to 2000 and by another 51 percent from 2000 to 2010.

However, black carbon's effect on snow is not linear. Menon's simulations show that snow and ice cover over the Himalayas declined an average of about one percent from 1990 to 2000 due to aerosols that originated from India. Her study did not include particles that may have originated from China, also known to be a large source of black carbon.

See "Black soot and the survival of the Tibetan glaciers," by James Hansen, et al., published last year in the Proceedings of the National Academy of Sciences. Also the figure is an average for the entire region, which saw increases and decreases in snow cover. As seen in the figure, while a large swath of the Himalayas saw snow cover decrease by at least 16 percent over this period, as reported by the National Snow and Ice Data Center, a few smaller patches saw increases.

Menon's study also found that black carbon affects precipitation and is a major factor in triggering extreme weather in eastern India and Bangladesh, where cyclones, hurricanes and flooding are common. It also contributes to the decrease in rainfall over central India. Because black carbon heats the atmosphere, it changes the local heating profile, which increases convection, one of the primary causes of precipitation.

While this results in more intense rainfall in some regions, it leads to less in other regions. The pattern is very similar to a study Menon led in 2002, which found that black carbon led to droughts in northern China and extreme floods in southern China.

"The black carbon from India is contributing to the melting of the glaciers, it's contributing to extreme precipitation, and if black carbon can be controlled more easily than greenhouse gases like CO2, then it makes sense for India to regulate black carbon emissions," says Menon.

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research for DOE's Office of Science and is managed by the University of California. Visit our Website at www.lbl.gov/

.


Related Links
Lawrence Berkeley National Laboratory
Beyond the Ice Age






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





ICE WORLD
Himalaya glacier error 'cost us dear': UN climate panel chief
London (AFP) Feb 3, 2010
The embattled chief of the UN climate change panel admitted Wednesday that a mistake in a landmark 2007 report had damaged the body's credibility, in an interview with a British newspaper. But Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change (IPCC), refused to apologise in the interview with the Guardian for the erroneous claim that global warming could melt Himal ... read more


ICE WORLD
Moon Exploration is Not Dead

Seed Bank For The Moon

Obama to propose abandoning US return to Moon: report

NASA Adds Israeli Technical Expertise To Lunar Science Research

ICE WORLD
Craters Young And Old In Sirenum Fossae

Spirit Prepares for Winter

A Stationary Spirit

Spirit Bogged In Sand: Now A Stationary Research Platform

ICE WORLD
Orbital Sciences Happy While Lockheed Is Sad

Dragon Spacecraft Completes Cargo Loading Milestone

CSF Comments On NASA Commercial Crew Program And Budget Increase

Obama trims US space ambitions

ICE WORLD
UK's First China Space Race Exhibition Launched

No Spacewalk From Tiangong-1

China's Mystery Spacelab

China launches orbiter for navigation system: state media

ICE WORLD
Russian cargo ship docks with ISS

Russia Sends Space Freighter To ISS

NASA Provides Inside Look At ISS With Streaming Video

Endeavour to bring high-tech 'sunroom' to ISS

ICE WORLD
Arianespace Wins ESA Contract

SpaceX And Spacecom Sign Contract

Arianespace To Launch The First Ten Galileo Satellites

Activities At Esrange Space Center 2010

ICE WORLD
New Technique For Detecting Earth-Like Planets

New technique helps search for another Earth

NASA's Rosetta "Alice" Spectrometer Reveals Earth's UV Fingerprint

Make A Play Date With Planet Explorers At The Adler

ICE WORLD
US book publishers smiling again as Kindle rivals emerge

Apple iPad to ignite tablet computer market: ABI

Google tailoring tablet computer software

New Simulation Tool Could Shorten Manufacturing Design Process




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement