Although deforestation contributes to less rainfall, to what extent some regions of the world, such as the Amazon rainforest, could see their rainfall reduced even more due to an increase in the amount of carbon dioxide (CO2 ) present in the earth’s atmosphere?
A study has examined the extent of this influence for the case of the Amazon rainforest, often nicknamed “the lung of the Earth.”
The higher the percentage of CO2 in the atmosphere, the less plants perspire, and the less moisture they emit into the atmosphere. This, therefore, tends to generate less rain.
The international team of David Montenegro Lapola, professor at the Center for Meteorological and Climate Research Applied to Agriculture (CEPAGRI), dependent on the University of Campinas (UNICAMP) in Brazil, has concluded that an increase of 50 percent the level of carbon dioxide (CO2) in the atmosphere could reduce rainfall in the Amazon as much or more than replacing the entire forest with pastures. Increasing CO2 would reduce the amount of water vapor emitted by the rainforest, causing a 12% annual decrease in the volume of rainfall, while total deforestation would reduce rainfall by 9%.
The results of this study constitute a warning about the need to act quickly and forcefully at the local level to reduce deforestation in the nine countries that share the Amazon basin and to act globally to reduce CO2 emissions into the atmosphere by from factories, vehicles, power plants and other large sources of CO2.
The direct effect that the increase in the amount of atmospheric carbon dioxide may have on the Amazon rainforest is a reduction in rainfall equivalent to or even greater than the reduction caused by the complete replacement of the forest by pastures. (Image: João Marcos Rosa / AmazonFACE)
Lapola is one of the coordinators of the AmazonFACE experiment. Installed not far north of Manaus, the experiment is aimed at increasing the level of CO2 in small patches of rainforest and will analyze the resulting changes in plant physiology and the atmosphere. The experiment could show the scenario of climate change that may be established on Earth within a few decades due to the action of global warming.
The study is titled “CO2 physiological effect can cause rainfall decrease as strong as large-scale deforestation in the Amazon”. And it has been published in the academic journal Biogeosciences, edited by the European Geosciences Union (EGU). (Source: NCYT from Amazings)