Tropical forests on the edge of critically high temperature range.Credit: bogdanhoria/ Getty Images
Tropical forests could be getting closer to a critical-high temperature threshold than previously anticipated, a new study suggests. The study, published in Nature, shows that the combination of climate change and local deforestation might push the hottest tropical forest regions dangerously close to, or potentially over, a critical temperature threshold if these forests experience an additional warming of around 4°C.
The researchers analysed land surface temperatures data from the world’s tropical forests in Central Africa, Asia, Australia, Brazil and Puerto Rico combined with high-resolution data from thermal imaging on the International Space Station.
They found that during hot and dry periods the canopy of tropical forests can reach temperatures of around 34°C, with some individual leaves going above 40°C. This study shows that more than 1% of tropical forest leaves are approaching and at times exceeding temperatures past which they cannot function.The critical temperature at which tropical trees' photosynthesis starts to fail is around 46.7°C. The study suggests that tropical forests can tolerate an increase in air temperatures of up to 3.9°C before their metabolic functions may be severely affected. However, there is still uncertainty about the adaptability of tropical trees and how leaf death might impact the overall health of forests.
Christopher Doughty, from the School of Informatics, Computing, and Cyber Systems, Northern Arizona University, warn that the 4.0 °C estimate is within “the ‘worst-case scenario” outlined in climate change predictions for tropical forests. However he points out that it is still possible to influence the fate of tropical forests, which are “vital bastions of carbon, water, and biodiversity,” Doughty says.
Doughty told Nature Africa that tropical forests are vitally important due to their biodiversity and climate regulating properties. Reducing carbon input into the atmosphere must be done at a global scale with global cooperation. However, reducing local deforestation should also be done at a more local/country scales.” he said.
