The Amazon rainforest is most likely now a net contributor to warming of the planet, according to a first-of-its-kind analysis from more than 30 scientists.
For years, researchers have expressed concern that rising temperatures, drought, and deforestation are reducing the capacity of the world’s largest rainforest to absorb carbon dioxide from the atmosphere, and help offset emissions from fossil-fuel burning. Recent studies have even suggested that some portions of the tropical landscape already may release more carbon than they store.
But the inhaling and exhaling of CO2 is just one way this damp jungle, the most species-rich on Earth, influences the global climate. Activities in the Amazon, both natural and human-caused, can shift the rainforest’s contribution in significant ways, warming the air directly or releasing other greenhouse gases that do.
Drying wetlands and soil compaction from logging, for example, can increase emissions of the greenhouse gas nitrous oxide. Land-clearing fires release black carbon, small particles of soot that absorb sunlight and increase warmth. Deforestation can alter rainfall patterns, further drying and heating the forest. Regular flooding and dam-building releases the...