Scary fact of the week
An American researcher has concluded that, by 2021, the Amazon rainforest will no longer be able to generate enough rainfall to sustain itself.
Monica de Bolle, a senior fellow at the Peterson Institute for International Economics in Washington DC, has warned that runaway deforestation coupled with the destructive policies of Brazil’s far-right president, Jair Bolsonaro, is pushing the forest towards the point where it will no longer be able to produce enough rainfall to sustain itself.
The latest thinking is that the rainforest makes the rain rather than the other way round. The forests pull in large amounts of water vapour from nearby areas and from nearby bodies of water. As the vapour condenses into rain, the atmospheric pressure drops and that sucks in yet more water vapour. This whole rainforest-water vapour system which maintains the forests of the Amazon Basin is called a biotic pump.
It is believed that the tipping point will come when 25% of the Amazon rainforest has been felled or burned. At this point the forest will not be able to generate enough rainfall to keep the biotic pump running and the forest will slowly degrade and revert to savannah-like grassland.
Already, more than 17% of the Amazon’s rainforest has been felled and Brazil’s space research institute has reported that deforestation in August this year was 222% higher than it was in August 2018. If this level of destruction continues it will bring the forests dangerously close to the estimated tipping point as soon as 2021.
The newly elected President Bolsonaro has vowed to develop the rainforest. He has attacked environmental protection agencies and refused international assistance with this year’s record breaking forest fires. His government is encouraging mining and agriculture in the Amazon Basin.
It has been calculated that the Amazon rainforest contains 10% of all biomass on Earth. This means that when deforestation takes place, the enormous amounts of carbon that the forest stores are released into the atmosphere as carbon dioxide. Some researchers think that when the rainforest reaches the dangerous tipping point at which it will no longer be able to sustain itself, it will be the Earth’s tipping point as well.