Study: *Impacts of Amazonian deforestation and projected twenty-first-century climate change on the South Asian summer monsoon*

Published in: *Global and Planetary Change*

Publication Date: November 2020

Authors: Yali Luo and others

Key Points:

-Amazon forest loss significantly reduces precipitation throughout the South Asian region during summer.

-The loss of Amazon forests affects the large-scale atmospheric circulation patterns, altering monsoon systems and leading to decreased precipitation.

-Amazon forest protection is crucial not only for local ecosystems but also for maintaining the regional and global climate and water resources.

Summary:

The Amazon rainforest plays a crucial role in regulating the global climate, affecting regional and global atmospheric circulation patterns and subsequently influencing monsoon systems worldwide. However, deforestation in the Amazon has raised concerns about its potential impact on monsoon rainfall in distant regions. This study aims to quantify the impacts of Amazonian deforestation and projected twenty-first-century climate change on the South Asian summer monsoon, which provides rainfall to nearly 1.2 billion people in the region.

Methods:

The researchers used climate model simulations with different scenarios. Specifically, they compared simulations without deforestation and simulations with varying degrees of Amazon deforestation, as well as simulations representing pre-industrial conditions and future projections under different climate change scenarios. The model analyzed precipitation patterns and other meteorological parameters to evaluate the impact of Amazonian deforestation on the South Asian summer monsoon.

Findings:

- Amazonian deforestation leads to significant reductions in precipitation and an increase in the frequency and intensity of droughts over the South Asian region during summer.

- The effect is particularly pronounced over the central and eastern parts of South Asia, where monsoon rainfall declines by 10% to 25%.

- The results suggest that Amazonian deforestation disrupts the global atmospheric circulation, including the Walker circulation and the Hadley circulation, which in turn alter the monsoon systems.

Implications:

- The study highlights the teleconnections between Amazonian deforestation and the South Asian summer monsoon, demonstrating that local land use changes can have far-reaching effects on regional climate patterns.

- The results emphasize the importance of Amazon forest protection, not only for preserving local biodiversity and regulating regional climate but also for maintaining the stability of monsoon rainfall in distant regions.