Rainforests across the tropics, from Indonesia to Central America and from Madagascar to the jungles around the Mekong River, are being cut or burned–to make way for ranches, farms, and palm oil plantations, to be logged for wood or cleared for roads and other human development. Around the world, 20 percent of the tropical rainforests have been cleared since the 1990s. Another 10 percent has been destroyed by climate change, which has increased temperatures, shorter dry seasons, and more frequent droughts.
A team of over 50 scientists and conservationists has now concluded that all this climate change is affecting the rich, damp forests. Forests are becoming less able to store carbon and water, and are at greater risk of collapse in many parts of the tropics. The projected rate of climate change, and the escalating land use activities could lead to forests becoming a source of carbon for the atmosphere.
Certain areas are more vulnerable than others. This team of experts, brought together by the National Geographic Society, with the support of Rolex, combined 40 years of satellite data with other forest observations to create a “vulnerability index,” which scientists plan to use in coming years to track which stretches of tropical rainforest need help the most urgently
It is possible for large areas of tropical rainforest to die or transition to a different state. That would devastate some of the most wildlife-rich regions on earth and potentially worsen climate change because intact rainforests slurp large volumes of carbon dioxide from the atmosphere. Although such a shift would generally occur slowly, scientists are concerned that forests like the Amazon could rapidly transform into something else.
“I think we all have this view that things are bad out there,” says Kristofer Covey, an ecologist and biochemist at Skidmore College and co-author of the study. The goal is to understand. What are the worst things? Which things are the worst? And to what extent? Can we use this information to make better future decisions?
They believe this will provide an early warning system that can direct limited conservation resources to the most vulnerable forests.
The state of tropical rainforests differs from one continent to the next. The Amazon is experiencing more water loss than Asian forests, and African forests are more susceptible to fire than others. Amazon forests are seeing a decline in productivity, but productivity is stable in Congo. However, productivity is increasing in tropical forests of China due to past abuses and substantial efforts to replant trees.
There are many ways to measure vulnerability of rainforests. Previous research focused mostly on small areas. Saatchi states that this confusion often confuses conservationists and researchers trying to determine the priority of forest restoration.
The Amazon continues to be at greatest risk
“The Amazon stands out as at particular risk even when considering it alongside other global rainforest challenges,” Covey says. “Widespread deforestation and a rapidly changing climate are significantly impacting ecosystem function across a variety of metrics,” Covey says.