Climate Benefits of Intact Amazon Forests and the Biophysical Consequences of Disturbance

The loss of forest cover in the Amazon has a significant impact on the local climate in Brazil, according to a new study by School of Earth and Environment researchers.

Using satellite data, Dr Jess Baker and Professor Dominick Spracklen, have evaluated the climatic consequences of deforestation in the Amazon between 2001 and 2013.

They found that deforestation causes the local climate to warm - and that warming intensified as the severity of deforestation increased.

Intact forests in the region, with less than 5% canopy loss, had the most climate stability over the ten years, showing only small increases in temperature. Areas that had tree cover reduced to below 70% warmed 0.44°C more than neighbouring intact forests during the study period.

The differences between intact and disturbed forests were most pronounced during the driest part of the year, when temperature increases of up to 1.5°C were observed in areas affected by severe deforestation. This increase is additional to global temperature rises driven by climate change.

“The Amazon wildfires have reminded us all of the important role that forests play in our global systems. But it cannot be overlooked that intact Amazon forests are also crucially important for Brazil’s own local climate. said Dr Baker.

“A healthy intact Amazon forest helps regulate the local climate and can even act as a buffer to the warming effects of climate change, compared with disturbed forests.” she continued.

“Deforestation decreases the amount of water emitted to the atmosphere from the forest through a process called evapotranspiration.” said study co-author Dominick Spracklen, a Professor of Biosphere-Atmosphere Interactions.

“Evapotranspiration can be thought of as the forest ‘sweating’; when the moisture emitted by the forests evaporates it cools the local climate. Deforestation reduces evapotranspiration, taking away this cooling function and causing local temperatures to rise. As temperatures rise this increases drought stress and makes forests more susceptible to burning.” he added.

Further information:

The paper Climate Benefits of Intact Amazon Forests and the Biophysical Consequences of Disturbance is published 30 August 2019.

It is part of a special issue on intact forests in Frontiers in Forests and Global Change.