School of GeoSciences

Global Change Ecology: Mathew Williams

Explainers - sharing our science

The role of Amazon forest loss on climate change

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Human activity has removed more than one tenth of trees and plants from the Amazon rainforest since the 1960s, according to our latest research (Exbrayat and Williams, 2015). The picture above shows the results of forest clearance in central Amazonia, with shrubs and trees regrowing.

Widespread removal of trees has contributed 1.5 per cent to the recent rise in the amount of carbon dioxide in the atmosphere, increasing the potential impacts of climate change.

Deforestation of the Amazon has only increased the total amount of carbon in the atmosphere very slightly compared to fossil-fuel emissions.

The rainforest would store 12 per cent more carbon in its vegetation, and cover a much larger area, had this deforestation not taken place.

Our study is the first to show the scale of Amazon deforestation by determining the impact humans have had on the ability of the rainforest to store carbon.

Trees absorb carbon dioxide from the atmosphere in order to grow, and this helps offset changes brought about by climate change.

We have made maps to show what size the Amazon would be today if humans had not deforested large areas of land.

High-resolution satellite images have only been available since 2000, so we made virtual models to work out how the rainforest changed in earlier decades. We used these to study how the loss of trees reduced the rainforest's ability to store carbon.

Destruction of large areas of the Amazon also impacts on the biodiversity of the rainforest and could lead to the loss of many animal and plant species.

Our study, published in the journal Geophysical Research Letters, was funded by the Natural Environment Research Council.

Our study indicates that the impact of large-scale deforestation on the Amazon carbon balance has been partially offset by ongoing regrowth of vegetation despite sustained human activity. Overall, our results provide a baseline to better understand the global carbon cycle.