Featured Research

from universities, journals, and other organizations

Dirty Snow May Warm Arctic As Much As Greenhouse Gases

Date:
June 7, 2007
Source:
University of California - Irvine
Summary:
The global warming debate has focused on carbon dioxide emissions, but scientists at UC Irvine have determined that a lesser-known mechanism -- dirty snow -- can explain one-third or more of the Arctic warming primarily attributed to greenhouse gases.

Annual mean temperature change due to dirty snow in degrees Celsius.
Credit: Image courtesy of University of California - Irvine

The global warming debate has focused on carbon dioxide emissions, but scientists at UC Irvine have determined that a lesser-known mechanism – dirty snow – can explain one-third or more of the Arctic warming primarily attributed to greenhouse gases.

Snow becomes dirty when soot from tailpipes, smoke stacks and forest fires enters the atmosphere and falls to the ground. Soot-infused snow is darker than natural snow. Dark surfaces absorb sunlight and cause warming, while bright surfaces reflect heat back into space and cause cooling.

“When we inject dirty particles into the atmosphere and they fall onto snow, the net effect is we warm the polar latitudes,” said Charlie Zender, associate professor of Earth system science at UCI and co-author of the study. “Dark soot can heat up quickly. It’s like placing tiny toaster ovens into the snow pack.”

The study appears this week in the Journal of Geophysical Research.

Dirty snow has had a significant impact on climate warming since the Industrial Revolution. In the past 200 years, the Earth has warmed about .8 degree Celsius. Zender, graduate student Mark Flanner, and their colleagues calculated that dirty snow caused the Earth’s temperature to rise .1 to .15 degree, or up to 19 percent of the total warming.

In the past two centuries, the Arctic has warmed about 1.6 degrees. Dirty snow caused .5 to 1.5 degrees of warming, or up to 94 percent of the observed change, the scientists determined.

The amount of warming by dirty snow varied from year to year, with higher temperatures in years with many forest fires. Greenhouse gases, which trap outgoing energy, are primarily responsible for the remaining temperature increase and are considered the Earth’s most important overall climate changing mechanism. Other human influences on Arctic climate change are particles in the atmosphere, including soot; clouds; and land use.

Humans create the majority of airborne soot through industry and fuel combustion, while forest and open-field fires account for the rest. Because of human activity, greenhouse gas levels have increased by one-third in the last two centuries.

“A one-third change in concentration is huge, yet the Earth has only warmed about .8 degrees because the effect is distributed globally,” Zender said. “A small amount of snow impurities in the Arctic have caused a significant temperature response there.”

Previous studies have analyzed dirty snow’s effect on climate, but this is the first to take into account realistic emissions from forest fires in the Northern Hemisphere and how warming affects the thickness of the snow pack.

In some polar areas, impurities in the snow have caused enough melting to expose underlying sea ice or soil that is significantly darker than the snow. The darker surfaces absorb sunlight more rapidly than snow, causing additional warming. This cycle causes temperatures in the polar regions to rise as much as 3 degrees Celsius during some seasons, the scientists say.

“Once the snow is gone, the soot that caused the snow to melt continues to have an effect because the ground surface is darker and retains more heat,” Zender said.

Dirty snow is prevalent in East Asia, Northern Europe and Northeastern United States.

Zender believes policymakers could use these research results to develop regulations to mitigate global warming. Limiting industrial soot emissions and switching to cleaner-burning fuels would leave snow brighter, he says. New snow falls each year, and if it contained fewer impurities, the ground would brighten and temperatures would cool. Carbon dioxide lives in the atmosphere for a century, so cutting back on emissions can prevent further warming but does not produce immediate cooling.

UCI scientist James Randerson and Philip Rasch, a scientist at the National Center for Atmospheric Research in Boulder, Colo., also worked on the study. The National Science Foundation and NASA funded this research.


Story Source:

The above story is based on materials provided by University of California - Irvine. Note: Materials may be edited for content and length.


Cite This Page:

University of California - Irvine. "Dirty Snow May Warm Arctic As Much As Greenhouse Gases." ScienceDaily. ScienceDaily, 7 June 2007. <www.sciencedaily.com/releases/2007/06/070606113327.htm>.
University of California - Irvine. (2007, June 7). Dirty Snow May Warm Arctic As Much As Greenhouse Gases. ScienceDaily. Retrieved August 28, 2014 from www.sciencedaily.com/releases/2007/06/070606113327.htm
University of California - Irvine. "Dirty Snow May Warm Arctic As Much As Greenhouse Gases." ScienceDaily. www.sciencedaily.com/releases/2007/06/070606113327.htm (accessed August 28, 2014).

Share This




More Earth & Climate News

Thursday, August 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Big Waves, Minor Flooding from Hurricane

Big Waves, Minor Flooding from Hurricane

AP (Aug. 27, 2014) Thundering surf spawned by Hurricane Marie pounded the Southern California coast Wednesday, causing minor flooding in a low-lying beach town. High surf warnings were posted for Los Angeles County south through Orange County. (Aug. 27) Video provided by AP
Powered by NewsLook.com
Calif. Quake Underscores Need for Early Warning

Calif. Quake Underscores Need for Early Warning

AP (Aug. 26, 2014) Researchers at UC Berkeley are testing a prototype of an earthquake early warning system that California is pursuing years after places like Mexico and Japan already have them up and running. (August 26) Video provided by AP
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Brazil Tries Genetically Modified Mosquitoes to Fight Dengue

Brazil Tries Genetically Modified Mosquitoes to Fight Dengue

AFP (Aug. 25, 2014) A factory in the industrial state of Sao Paulo produces genetically modified mosquitoes to fight dengue, a deadly tropical disease more prevalent in Brazil than anywhere else in the world. Duration: 00:57 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins