Africa's Congo rainforest has experienced drastic loss of greenness in the past decade due to climate change, according to a University at Albany and State University of New York study.
The finding was based on a new analysis of NASA satellite data of the second largest tropical rainforest in the world. For the study, researchers used Enhanced Vegetation Index to determine the percentage of green cover in the Congo rainforest. The greenness is deemed to be one of the reliable indicators of forest health.
The researchers observed steady decrease in greenness, also sometimes referred to as browning. The slow response of Congo forest is in contrast with the quick reaction in the Amazon, where tree mortality is witnessed on a large scale.
Besides the browning of forest canopy, climate factors also posed an extra stress on the vegetation growth including higher land surface temperatures and decreased cloudiness. Although low-level cloud cover increases photosynthesis, it also results in the depletion of soil moisture.
"Forests of the Congo Basin are known to be resilient to moderate climate change because they have been exposed to dry conditions in the past few hundred years," Sassan Saatchi of Jet Propulsion Lab, co-author of the study, said in a news release. "However, the recent climate anomalies as a result of climate change and warming of the Atlantic Ocean have created severe droughts in the tropics, causing major impacts on forests."
The researchers found that the persistent drought since 2000 can affect the biodiversity and carbon storage of the Congo rainforest. It can also lead to habitat loss of 400 species of animals (including elephants, chimpanzees, bonobos, and gorillas among others); 10, 000 species of tropical plants (30 percent unique to the forest); 1000 species of birds and 700 species of fish, according toWorld Wildlife Fund.
"It's important to understand these changes because most climate models predict tropical forests may be under stress due to increasing severe water shortages in a warmer and drier 21st century climate," researcher Liming Zhou said.
In further studies, researchers would be analyzing the effects of climate change on individual tree species. It is believed that severe droughts might benefit deciduous trees at the cost of evergreen trees.
The study is published in the journal Nature.
