It will also cause climate feedbacks that will decrease the productivity of pasture and soybeans – the reason advanced for felling the trees in the first place.
The researchers are from the Brazilian federal universities of Viçosa, Pampa, Minas Gerais and the Woods Hole Research Center in the United States.
They predict that by 2050 a decrease in precipitation caused by deforestation will reduce pasture productivity by 30 percent in the governance scenario and by 34 percent in the business-as-usual scenario.
They say increasing temperatures could cause a reduction in soybean yield by 24 percent in the governance scenario and by 28 percent under the business-as-usual scenario.
Stark conclusion It is significant that the study finds relatively little difference between the outcomes of the two scenarios, perhaps suggesting that Brazil needs to tighten its environmental legislation drastically and to enforce it more effectively.
Perhaps the authors’ starkest conclusion is that a combination of the forest biomass removal itself, and the resulting climate change, which feeds back on ecosystem productivity, could result in biomass on the ground declining by up to 65 percent between 2041 and 2060.
And all this would achieve little or nothing in terms of food production. The researchers write: “Total agricultural output may either increase much less than expected proportional to the potential expansion in agricultural area, or even decrease, as a consequence of climate feedbacks from changes in land use.
“We expected to see some kind of compensation or off-put, but it was a surprise to us that high levels of deforestation could be a no-win scenario – the loss of environmental services from the deforestation may not be offset by an increase in agricultural production.”
The study shows that the effects of deforestation will be felt most in the eastern Pará and northern Maranhão regions. Here the local precipitation appears to depend strongly on the forests, and changes in land cover would drastically affect the local climate, possibly to the point where agriculture became unviable.
“Beyond this limit, the feedbacks that we demonstrated start to introduce significant losses in agricultural production.”
This article originally appeared at The Daily Climate, the climate change news source published by Environmental Health Sciences, a nonprofit media company.
