Brazilian savannah

Denis A. C. Conrado

[RIO DE JANEIRO] Global warming alone will cause an 18 per cent reduction in Amazon tropical rainforest if the most severe scenario projected by the Intergovernmental Panel on Climate Change (IPCC) becomes reality.

The study ― from Brazil's National Institute of Space Research (INPE) and the Institute of Aeronautics and Space ― only considers the effect of climate change on vegetation and not the impact of human deforestation activities.

"If we consider human deforestation, the forest loss would be even more severe," says lead researcher Luis Salazar, from the INPE.

The area will be replaced by savannah by the year 2099, say researchers.

The study ― to be published in Geophysical Research Letters ― combines data from models of vegetation distribution in Brazil with data from IPCC climate models.

The calculations are based on the IPCC's most severe scenario of greenhouse gas emissions, which predicts an increase of 2–6 degrees Celsius in regional temperatures this century.

According to the researchers, the loss of this tropical forest will increase the area currently covered by savannah ― characterised by grasslands with scattered trees and drought-resistant underbrush ― by almost 30 per cent.

The researchers estimated the forest loss over the century in three stages, with 3.1 per cent disappearing by 2029, and 9.3 per cent by 2059.

They predicted that the southeastern region of the Amazon ― located near the border of the current savannah ― would suffer most of the losses.

"Our findings reinforce the need of climate change mitigation to avoid a dangerous interference with the ability of natural ecosystems to adapt to it," said Salazar.

Conversely, the researchers point out that this century's projected climate conditions will be favourable to the Brazilian Atlantic rainforest, with an increase in area of around two per cent.

"Unfortunately, changes in the land-use have left only seven per cent of its original area," said Salazar.