Black carbon: a short-lived warming agent with big effects
Climate Progress reported yesterday on a new study about the warming effects of black carbon published in the peer reviewed journal Journal of Geophysical Research-Atmospheres. The study reveals that black carbon (dark particles of soot emitted by various kinds of combustion) is roughly twice as powerful a warming agent as previously thought, and it is the second most important climate forcing agent after carbon dioxide in terms of warming experienced thus far (methane is a close third).
The figure below, taken from the article, summarizes the complexities surrounding black carbon’s emissions and effects.
This research is important because:
1) It is yet another example (like the melting rate of Greenland’s glaciers) where the climate models have in the past significantly underestimated the warming effects of human activities. As we learn more, the climate problem continues to grow more worrisome.
2) Unlike carbon dioxide, nitrous oxide, and methane, black carbon (BC) has a very short lifetime in the atmosphere (on the order of a week). Reductions of BC emissions will lead to rapid reductions in the warming effect, so we can have a big impact on warming relatively quickly, if we focus on the sources of those emissions that exert the highest warming effect.
3) BC emissions (in the form of small particulate matter) are tied to significant human health effects, and the benefits of reducing these emissions are large enough to justify reducing them, irrespective of climate benefits. The World Health Organization estimates that about 2 million people die each year from pollution from indoor combustion of solid fuels, the same kinds of combustion tied to BC emissions.
4) The biggest sources of BC are burning forests and savannas, coal and biomass in residential applications, and diesel fuel. As the world warms, it’s likely that black carbon from burning forests will increase, which is a positive feedback associated with a climate change.
5) Even if we are successful in reducing BC emissions, we’ll still need to reduce emissions of carbon dioxide, methane, nitrous oxide, and other long-lived forcing agents, because their long-term effects remain a real concern.
Related posts
Cold Cash, Cool Climate: A summary of the argument
Why climate change causes BIG increases in severe weather
An effective graph summarizing the climate conundrum
Why fossil fuel abundance is an illusion
