The new research suggests that leaf death could become a new factor in the predicted"tipping point" where tropical forests transition due to climate change and deforestation into savannah-like landscapes.
A tiny percentage of upper canopy leaves have already crossed that threshold, reaching temperatures so high—above 47 degrees Celsius—as to prevent photosynthesis, the study published inCurrently, some leaves exceed such critical temperatures only 0.01 percent of the time, but impacts could quickly scale up because leaves warm faster than air, the researchers said.of these leaves goes up by eight degrees," lead author Christopher Doughty of Northern Arizona University told journalists.
Doughty and his team used data from the NASA ECOSTRESS satellite—designed to measure plant temperatures—validated with ground observations, based in part on sensors attached to individual leaves.There remain uncertainties as to how high leaf temperatures might impact the forest as a whole, the scientists cautioned.
They also harbor half or more of the world's plant biodiversity, with at least 40,000 different tree species, according to the Intergovernmental Panel on Climate Change .