Scripps Institution of Oceanography, UC San Diego researchers say carefully balanced mitigation of air pollution is necessary to keep greenhouse effects in check after an analysis of east Asian air sampled during and after the 2008 Summer Olympics in Beijing.

Soot and other forms of the particulate air pollutant black carbon vary in their ability to cause global warming, meaning that the effects of pollution control campaigns will vary based on which sources of pollution are targeted. Black carbon is a major component of soot — produced in diesel exhaust, wood-burning and other activities — and is increasingly viewed as a major contributor to global and regional warming. American and Korean scientists behind the analysis found that fossil fuel-based soot particles ejected into the atmosphere are more efficient at trapping sun’s heat than soot particles produced by biomass burning.

The difference comes from the relative amount of sulfates intermingled with each type of black carbon. Brightly surfaced sulfate particles are often produced during the burning of coal and other fossil fuels but can have a mitigating effect against global warming by reflecting solar radiation instead of absorbing it. Removal of sulfate pollution without corresponding removal of black carbon could exacerbate global warming by diminishing their net cooling effect.

Results of the National Science Foundation-funded study appear in the July 25 online issue of the journal Nature Geoscience.

“In-situ sampling of air can give us practical insights into mitigation of climate change,” said Scripps climate and atmospheric scientist Veerabhadran Ramanathan, the study’s lead researcher.

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Smoke rises from a clay stove and blackens the walls of a poorly ventilated kitchen hut somewhere in south Asia. The smoke eventually escapes and adds to a perpetual haze that darkens the horizons over large swaths of poverty-filled regions.

The smoke continues to rise. Its floating soot particles heat the atmosphere as they absorb sunlight and at the same time, they may also cool things at ground level with the dimness they provide. The soot and other forms of black carbon eventually fall back to the ground, having traveled as far as the Himalayas. Onto this bright snow and ice they add a veneer of blackness that hastens melt rates and diminishes glacial stores of drinking water.

The practice of biomass burning – using sticks, grass, or cow dung as free cooking fuel – combines with the production of diesel exhaust from vehicles everywhere to create a large contributor to global warming, possibly second only to carbon dioxide emissions. By accelerating snowmelt, it makes the planet more heat-absorbent as sunlight falls less on the bright ice and snow and more on dark land and water.

[See related coverage: Is global warming making us sicker?]

This smog, of course, has other unpleasant side effects carbon dioxide doesn’t have. The women using crude cookstoves and the children at their feet are first in line to suffer from respiratory problems every time they prepare a meal. Household black carbon emissions have been estimated to cause 2 million or more premature deaths throughout the developing world every year. Even with the smog control efforts in urban areas of the developed world, pollution continues to affect health even in relatively affluent countries.

Veerabhadran Ramanathan, a professor of climate and atmospheric sciences at Scripps Institution of Oceanography at UC San Diego, was one of those children. Spending summers with his grandmother in the village of Eraharam in southern India, he would watch her wheeze through the cooking hour, preparing dishes with a delicious smoky flavor infused at great cost.

Ramanathan grew up to be a scientist who was among the first to understand on a regional and global scale how particulate pollution can simultaneously attenuate and accelerate global warming. His career tracks neatly with the growth of public awareness of climate change and the dangers it poses to the planet. Now his newest project is informed as much by memory as by data.

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Despite oft-repeated claims by sources ranging from the United Nations to music star Paul McCartney, it is simply not true that consuming less meat and dairy products will help stop climate change, says a University of California authority on farming and greenhouse gases.

UC Davis Associate Professor and Air Quality Specialist Frank Mitloehner says that McCartney and the chair of the U.N.’s Intergovernmental Panel on Climate Change ignored science last week when they launched a European campaign called “Less Meat = Less Heat.” The launch came on the eve of a major international climate summit, which runs today through Dec. 18 in Copenhagen.

McCartney and others, such as the promoters of “meatless Mondays,” seem to be well-intentioned but not well-schooled in the complex relationships among human activities, animal digestion, food production and atmospheric chemistry, says Mitloehner.

“Smarter animal farming, not less farming, will equal less heat,” Mitloehner said. “Producing less meat and milk will only mean more hunger in poor countries.”

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Tackling climate change by reducing carbon dioxide and other greenhouse emissions will have major direct health benefits in addition to reducing the risk of climate change, especially in low-income countries, according to a series of six papers appearing today (Nov. 25) in the British journal The Lancet.

Two University of California, Berkeley, authors of the papers — Kirk R. Smith, professor of global environmental health, and Michael Jerrett, associate professor of environmental health sciences — presented the results today at a press conference in Washington, D.C.

The press conference, held at the end of a half-day discussion of the studies’ policy implications, also included Linda Birnbaum, director of the National Institute of Environmental Health Sciences (NIEHS) and National Toxicology Program. United Kingdom coauthors were patched in via satellite from London, where they participated in a simultaneous forum and press conference.

The studies, three of them coauthored by Smith and one coauthored by Jerrett, used case studies to demonstrate the co-benefits of tackling climate change in four sectors: electricity generation, household energy use, transportation, and food and agriculture.

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UCTV’s  magazine program features a look at how doctors at UC Davis’ Pain Management Clinic are teaching patients to cope with chronic pain without becoming addicted to drugs. Then, another angle on climate change – what UC scientists are discovering about its impact on human health. And finally, from the Scripps Institution of Oceanography at UC San Diego, searching for exotic medicines in the tropics of Panama.

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