NASA scientists have designed an index to assess the impact of global warming and human exploitation on the world's largest tropical forests. Their study shows that the Amazon is less resilient than the Congo Basin forest.
From Siberia and Australia to Greece, Brazil, Turkey, Sardinia, Canada and California... this summer, the list of areas of the world facing devastating and deadly fires is sadly long. But tropical forests such as the Amazon, the Congo Basin or those of Southeast Asia (especially Borneo, in Indonesia) are facing two major threats: global warming and deforestation due to human activity.
In order to assess the precise impact on every rainforest on the planet, scientists at NASA's Jet Propulsion Laboratory (in Southern California, USA) have developed the "tropical forest vulnerability index (TFVI)." This tool, accessible to scientists as well as the general public, makes it possible to evaluate the possible tipping points, which could see tropical forests turn into savannas.
"The hope is that the larger global community of scientists and policy makers, particularly in tropical countries, will now make use of the index to systematically assess the vulnerability of rainforest resources and to develop nature-based solutions to meet their commitments to the Paris Agreement," notes Sassan Saatchi of NASA's Jet Propulsion Laboratory, in a news release.
The study00344-4), published in mid-July in the One Earth journal, shows that the three main rainforest areas of the world cited above have different degrees of sensitivity to deforestation and climate change. Since the 1990s, 15-20% of tropical forests have been cut down and another 10% have been damaged by fire.
The Amazon is the most threatened forest in the world, both by drought and by exploitation. The Congo Basin, however, is more resilient, partly because it has been facing drought for a longer period of time, even though it is subject to extreme climatic conditions similar to those in the Amazon. Meanwhile, "in Asia, tropical forests appear more vulnerable to land use and fragmentation," the study notes.
The index was designed using data combining satellite and soil recordings from 1982 to 2018, as well as global precipitation measurements. Researchers then correlated stressors (temperature, water availability, extent of degradation) with data on the amount of living forest biomass, the ability of plants to absorb carbon dioxide, and the amount of water released by trees into the atmosphere.
