Faster dieback of rainforests altering tropical carbon sinks under climate change
Debashis Nath, Reshmita Nath, Wen Chen
Abstract
Carbon sinks in the tropical rainforests are restricting the global warming to attain unprecedented heights. However, deforestation and climate change is switching them to a net carbon source at some of the deforested patches. Using machine learning algorithm we predict that more than 50% of the tropical rainforests will undergo rapid “Savannisation”/transformation by the end of 21 st century under high emission scenarios. Climate change projects ‘El Niño-like’ warming condition, which decreases precipitation in the rainforests and favors atmospheric dryness. In Central Amazonia vegetation degradation saturates the carbon sink and more than 25% of the rainforests will transform into a net carbon source due to increase in soil microbial respiration. This transition will accelerate if Eastern Pacific/Global temperature warms beyond 1.5 ◦ K/2.3 ◦ K (by 2050’s) and will undergo a steeper transit by ~2075 (2.45 ◦ K/3.8 ◦ K warming). This alteration will exacerbate global warming and has consequences for policies that are intended to stabilize Earth’s climate.