This article discusses how a combination of El Niño and climate change might spell the end for tropical forests.
- NASA’s Orbiting Carbon Observatory-2 (OCO-2) allowed scientists to study the response of the world’s tropical rainforests to the 2015-16 El Niño in more detail than every before, potentially providing insight into the longer-term response of tropical forests to escalating climate change.
- During the El Niño, OCO-2 recorded a sudden global surge in CO2 emissions (above 400 ppm for a full year, the highest in modern history), an effect significantly enhanced by tropical forest emissions in South America, Africa, and Southeast Asia – all responded to the El Niño by temporarily shifting from carbon sink to carbon source.
- However, each region responded differently: El Niño brought extreme drought to South America, and trees there stopped absorbing CO2. In Southeast Asia, major forest fires raged in extremely dry conditions, quickly releasing stored carbon. In Africa, rainfall was normal, but high temperatures drove increased ecosystem respiration.
- Scientists worry that a tipping point could be reached where tropical forests collapse, but more study is needed. Given the great uncertainties as to how tropical forests will respond to a warming world, taking action now to keep forests standing and healthy may offer the single best hope for mitigating negative impacts, say researchers.