Amazon deforestation may shrink Himalayan snow and Antarctic ice

Rapid deforestation of the Amazon rainforest could influence the temperature and precipitation over the Tibetan plateau 15,000 kilometres away.

Saini Yang at Beijing Normal University in China and her colleagues analysed global climatological data from 1979 to 2019 to identify correlations in temperature and precipitation between the Amazon rainforest and other areas. Such links are called “teleconnections”.

They focused on the Amazon rainforest in particular because of its significance as a major carbon sink and as a climatic “tipping point” that could see forest turn to savannah beyond a certain threshold of warming and human-driven deforestation.

The researchers found that since 1979, warm temperatures in the Amazon correlated with warm temperatures over the Tibetan plateau and the West Antarctic ice sheet; more precipitation in the Amazon was associated with less precipitation in those regions.

By analysing changing temperatures in the regions between the Amazon and those distant areas, they were also able to trace the path through which energy or materials such as black carbon released in forest fires might propagate through the atmosphere. Their analysis showed the route remained consistent under different future warming scenarios.

The collapse of the West Antarctic ice sheet is a known tipping point. Melting snow on the Tibetan plateau is not, but the region is warming more rapidly than much of the rest of the globe, and changes to snow and ice there could have consequences for ecosystems and the billions of people that rely on its snowmelt for water, says Yang.

Victor Brovkin at the Max Planck Institute for Meteorology in Germany says the teleconnections are an interesting find, but is sceptical that variability in the Amazon causes the changes elsewhere. He says the Amazon is too small an area to overcome the influence of the tropical oceans and the researchers don’t present a physical mechanism to explain any influence.

If the Amazon does have an influence on these regions however, it could mean there is a higher risk the Amazon tipping point might set others off, says Jonathan Donges at the Potsdam Institute for Climate Impact Research in Germany. “It adds an additional potential domino that can fall.”