Soot from vehicle exhaust, power generation and burning biomass is the second most important contributor to global warming. Photo: euthophication & hypoxia via flickr.
More on the high, but heretofore largely neglected, role that soot plays in increasing global warming: Research from Stanford University shows that soot is second only to carbon dioxide in its warming contribution, and that reducing it may be the only way we can stop Arctic sea ice melting. In doing so we'll also prevent some 1.5 million premature deaths annually due to improved air quality.Soot Comes Out of the Atmosphere in Weeks, Not Decades
Since soot--which in this context comes from older diesel engines and burning other fossil fuels, industrial sources, inefficient biomass cookstoves used in many developing nations--comes out of the atmosphere in a matter of weeks, not decades or centuries like carbon dioxide or other greenhouse gases, removing the source of pollution is highly effective in both stopping the warming effects as well as improving air quality.
See animation of Arctic sea ice decline at NASA; image via flickr
Clean Energy, Electric Vehicles & Rural Electrification the Solution
But back to the research itself... Stanford's Mark Jacobson examined the effects of two types of soot (black & brown), from both burning fossil as wells as burning biomass, on heating clouds, snow and ice. He found that the combination of this soot has a greater warming effect than methane, which is normally classified as the second most important contributor to the greenhouse effect.
Jacobson says that eliminating this soot could reduce warming above the Arctic Circle by up to 1.7°C over the next 15 years. Over the past century the Arctic has warmed by at least 2.5°C, and is continuing to warm.
The study found the lowest-cost, most-effective way of quickly reducing soot is to put particle traps on vehicles burning fossil fuels and by converting vehicles to run on electricity generated from clean sources. In areas where biomass cookstoves are the norm, Jacobson says providing electricity to these areas from clean sources, would reduce the use of biofuels for heating and cooking, thereby reducing both the amount of soot produced as well as having major positive health effects.
Read more: Stanford University
Aerosols Also Implicated in Glacier Melting, Changing Weather Patterns
Other research examining the effects of soot on melting glaciers and changing weather pattens in South Asia has reached similar conclusions: Beyond increasing atmospheric warming, because the soot coats the surface of the snow and ice it changes the albedo of the surface, allowing it to absorb more sunlight and thereby accelerating melting.
Furthermore due to the atmospheric warming effect of soot, it has been cited as "a major factor in triggering extreme weather in eastern India & Bangladesh," as well as being linked to decreases in rainfall in central India.
photo: McKay Savage via flickr
In the United States, new research from the City College of New York on the effects of particle pollution on weather patterns around Manhattan has shown that aerosols can either increase or decrease local rainfall, sometimes creating situations where one area will be deluged while a neighboring town will remain dry.
In short, aerosols can be linked to poorer air quality (both indoor and outdoor) and deaths because of this, changing short-term weather patterns, and long-term climatic changes contributing to melting of both Arctic sea ice and glaciers. The good news is, once the source of pollution is removed or reduced, the effects stop comparatively quickly.
More on Global Warming Causes:
90% of Himalayan Glacier Melting Caused by Aerosols & Black Carbon
Black Soot Coating Himalayan Glaciers is Accelerating Melting
Ignoring Soot Pollution Means We're 8 More Years Behind Schedule in Tackling Climate Change
Cargo Ships Emit Twice As Much Soot As Previously Thought