Asia and soot: Black carbon even worse than thought
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Asia and soot: Black carbon even worse than thought

A new study published in the Journal of Geophysical Research-Atmospheres claims that black carbon, or soot, is twice the climate change driver as previously estimated by the UN Intergovernmental Panel on Climate Change (IPCC).

Black carbon is produced by incompletely burning fossil fuels and biomass (wood, crop waste, dung etc.) in low tech and dirty ways, such as with open fires, rudimentary cooking stoves, slash and burn agriculture and fuel oil-burning cargo ships. Besides being poisonous and resulting in medical problems such as low birth weight and cardio-pulmonary diseases, black carbon is a powerful, “short-lived climate forcer”. This means that the impact on climate caused by soot is, in comparison to CO2, is immediate and doesn’t last long. Therefore cutting black carbon has been viewed as a “quick fix” for climate change.

From the Times of India:

The new assessment found black carbon emissions caused significantly higher warming over the Arctic and other regions, could affect rainfall patterns, including those of the Asian monsoon system, and have led to rapid warming in the northern United States, Canada, northern Europe and northern Asia.

The study found that a lot more black carbon is produced globally than previously thought. Installing filters and changing habits in areas where people produce large amounts of soot by burning coal and biomass could lower temperatures in the short term, buying more time for reducing CO2 emissions.

One of the co-authors of the new report, Professor Piers Forster of Leeds University, is quoted in the Independent:

There are exciting opportunities to cool climate by cutting soot emissions, but it is not straightforward. Reducing emissions from diesel engines and domestic wood and coal fires is a no-brainer, as there are tandem health and climate benefits. If we did everything we could to reduce these emissions, we could buy ourselves up to half a degree [Celsius] less warming, or a couple of decades of respite.

However, soot also contains elements that block the sun and cool the climate, so the issue is not so straightforward as simply reducing all black carbon-producing practices. Burning vegetation out in the open may have an aggregate cooling effect, according to Forster, who believes cutting soot from diesel engines is a good way to start.

Either way, soot and smog are having catastrophic effects on human health, especially in Asia. Reducing black carbon is worth it in terms of both immediate health benefits as well as short-term climate change.

Read more from BBC News and Science 2.0.


Indoor cooking fire, India, pic: Karan Singh Rathore /