The Amazon rainforest is vulnerable through a combination of human influences, including deforestation, fire and climate change. As the world’s largest store of biodiversity and a major sink for carbon dioxide, the future fate of the Amazon rainforest is of concern to us all. Due to its exceptional biodiversity, around one quarter of all terrestrial species are currently found in the Amazon. The Amazon also represents a major sink for human emissions of carbon dioxide, currently absorbing around 2 billion tons per year. However, this buffer against rising greenhouse gas concentrations is vulnerable, as highlighted by the two major droughts in the past 10 years (in 2005 and 2010).
The 2005 and 2010 droughts!
These two droughts both caused substantial carbon loss turning the forest from a sink to a temporary source of carbon (if all was converted to carbon dioxide, equivalent to an impact of around 5 billion tons for each event). Some negative effects of the 2005 drought persisted for several years after the event. While the causes of these events are not well understood, they demonstrate that substantial drought is possible, and that the forest is sensitive to such rainfall deficits. Other recent work has confirmed that global forest species tend to have relatively narrow tolerance of drought. A concern exists that such droughts could become more common in the future, through climate change, but the fate of the Amazon is an even more complex question.
Amazon vulnerability to climate change from increased carbon dioxide – read how?
Even considering just the effect of future climate change from increasing carbon dioxide, the range of possible outcomes for the Amazon is large. A broad range of climate changes are projected, associated in part with uncertainty in how the tropical Pacific and Atlantic sea-surface temperatures will respond in the future and how this will influence regional rainfall patterns . However, climate models do show greater agreement on the risk of future drought in the eastern part of the Amazon.
*exerts from the Met Report on Amazon Dieback 2013