In Africa, more fire equals less rain

Every year, subsistence farmers set fire to the savannas and outlying tropical forests of Africa - in the north during the winter and in the south during the summer. All together, the carbon emissions from these African fires account for 50% of the total global fire emissions in any given year! (That's a lot)

In previous work I've shown that fires in tropical regions can significantly impair the atmosphere's ability to build rain clouds (in science-land we call these clouds cumulus or cumulonimbus), and that the global effect from fires can substantially alter the wind circulation on Earth.

However, one thing all these previous studies have in common is that they relied heavily on climate models. Here at JPL, I've been exploring whether we can answer the question "what happens when smoke gets into clouds?" using only satellite data. (Luckily, here at NASA, we have plenty of satellite data)

The result is a recent manuscript published in the journal Geophysical Research Letters, where we showed that, during days when smoke emissions from fires were high, clouds were not allowed to grow like they would if the atmosphere was unpolluted.

NASA, in tandem with JPL, issued a press release on our findings, which were also picked up by Roland Pease of the BBC World Service who featured them on a recent episode of "Science in Action" (my interview starts around 21:30).