What’s black and dirty and messing with the climate?
Soot, derived from many sources, needs to be looked at more closely by atmospheric researchers.
PRNewsFoto/Green Works/Laura Morton
Soot nags at climate scientists like a child demanding a parent’s attention. While soot has played a minor role compared with the rock stars of climate change – carbon dioxide and other greenhouse gases – that perspective is changing. Recent research suggests that black carbon soot must be reckoned with.
Soot particles affect cloud formation and precipitation. Because it absorbs sunlight, soot can cool the surface while warming air aloft. The balance between such warming and cooling affects regional climates.
Last week, the Proceedings of the National Academy of Sciences carried a report by Renyi Zhang at Texas A&M University and colleagues on the first study of what happens when the dirty black particles soak up sulfuric acid. This combination significantly changes the role these particles play in the atmosphere.
These changes could have “profound implications on visibility, human health, and direct and indirect climate forcing,” the scientists note, adding that the details of these processes “remain highly uncertain, considerably hindering efforts to assess their impact on visibility, human health, and climate.”
Clearing up that uncertainty should be a research priority.
Last March, V. Ramanathan at Scripps Institution of Oceanography and Greg Carmichael at the University of Iowa reviewed what’s known about soot’s effects in Nature Geoscience. They noted that black carbon pollution could be the most powerful agent driving global warming after carbon dioxide. They said it’s time “to examine if black carbon is also having a large role in the retreat of arctic sea ice and Himalayan glaciers as suggested by recent studies.”