New Study Shows Tropical Forests at Risk as Leaves Overheat
A new study has revealed that leaves in tropical forests across South America and Southeast Asia are reaching dangerously high temperatures that could hinder their ability to photosynthesize. The study, published in Nature, highlights the potential consequences for the world’s forests.
The researchers found that leaves begin to fail in their photosynthetic process when their temperatures exceed 46.7 degrees Celsius (116 Fahrenheit). While this may seem high, the study shows that leaves can get much hotter than the surrounding air temperature. Using temperature data from thermal satellite sensors on the International Space Station and on-the-ground observations, the scientists discovered that some forest canopy temperatures exceeded 40 degrees Celsius (104 Fahrenheit).
Currently, only 0.01% of leaves are passing the critical temperature threshold, but as the world warms, this percentage is expected to increase. The report warns that if global warming exceeds 4 degrees Celsius (7.2 Fahrenheit), the amount of leaves surpassing critical temperature thresholds could rise to 1.4%, potentially causing large-scale leaf loss and tree deaths. Tropical forests cover approximately 12% of the planet and are home to more than half of the world’s species. They also play a crucial role in carbon absorption and climate regulation.
“There are all sorts of potential feedbacks once you start losing bits of forests, even leaves on individual trees,” said Christopher Doughty, a report author and associate professor in ecoinformatics at Northern Arizona University.
While the figures may seem small, the risk is significant due to the critical role tropical trees play in sustaining life, the climate system, and the planet. Almost all life, including humans, depends on photosynthesis for food either directly or indirectly. Kevin Collins, a senior lecturer in environment and systems at the Open University, emphasized the importance of tropical forests, stating, “The findings indicate that global warming is putting this vital process at risk.”
However, Chloe Brimicombe, a climate scientist at the University of Graz, cautioned that the study’s numbers are small and tropical forests may be more resilient to climate change than suggested. She highlighted the complexity of trees and forest dynamics. Nonetheless, the report authors stress the importance of their research in providing insights into how tropical forests will respond to climate change.
“It’s a little bit of a canary in the coal mine that we’re starting to see,” said Joshua Fisher, a climate scientist at Chapman University and a report author. He emphasized the need to detect these changes before they become widespread.
While global warming poses a risk to tropical forests, the study also highlights other immediate concerns, such as deforestation, wildfires, and droughts. Christopher Still, a forest ecosystem professor at Oregon State University, emphasized the need to focus on not just drought but also the temperatures leaves are reaching.
Overall, the study underscores the vulnerability of tropical forests to climate change and the potential repercussions for global ecosystems and the planet’s future.