Last night I watched an interesting documentary on the Amazon rainforest dealing with the consequences of a changing climate. The documentary is part of the 6-prt TV climate series ‘Tipping points’ and investigates how the rainforest manages to deal with our shifting climate.
Parts of the forest show first signs of changes, with big trees dying and fewer growing as these trees need a lot of water to stay healthy. While the death of such huge trees causes a fair bit of destruction, new trees emerge in the gaps. However, these are smaller trees that need less water and grow less high. Together with deforestation, fires and more frequent draughts it is a first step towards an ecological tipping point where our rainforests could turn into savannahs.
Often rainforests are described as our lungs, as they remove carbon dioxide from the atmosphere and produce oxygen and keep our atmosphere in balance by doing so. Recently NASA found that the Amazon inhales more CO2 than it emits and the forest therefore reduces global warming. However, when dying the forests releases CO2 into the atmosphere, which is estimated to be 1.9 billion tons each year.
Deforestation and fires to clear forest for farmland has already changed the regional climate drastically in terms of rainfall patterns and distribution.
Furthermore, the climatic phenomenon of the El Nino Southern Oscillation is associated with dry conditions in Brazil and the northern Amazon and its frequency increased in the past years and is expected to further increase in the future.
This is a drastic change for nature and for humans as we rely on these forests to somehow keep our atmosphere in balance.
The rainforest stores an equivalent of about 15 years of human-caused emissions in its soil and biomass and a massive die-back could greatly accelerate climate change. About 2 billion tons of CO2 are taken out of the air each year by the rainforests photosynthesis, however, during draughts in 2005 and 2010 this process reversed with 3 billion tons of CO2 emitted by the Amazon. This caused a net 5 billion ton increase in CO2 to the atmosphere.
Our changing climate, fires and more frequent draughts in change with sudden floods are pushing the Amazon to a tipping point and we are closer than you would think, with large areas dying or being already dead. If we loose the rainforest, the climate will change drastically and nature will never be the same, as we know it now.