Amazon deforestation may start feeding on itself

Source: The Economist

From The Economist:

SINCE THE 1970s nearly 800,000km² of Brazil’s original 4m km² (1.5m square miles) of Amazon forest has been lost to logging, farming, mining, roads, dams and other forms of development—an area equivalent to that of Turkey and bigger than that of Texas. Scientists worry this is uncomfortably close to the threshold for tree loss, of between 20 and 25%, beyond which deforestation begins to feed on itself, turning much of the Amazon basin into drier savannah known as cerrado. Under Jair Bolsonaro, the right-wing president of Brazil who was inaugurated in January, the Amazon appears to be rushing towards that tipping point.

The deforestation rate had slowed between 2004 and 2012, when the government beefed up its environmental protection agency, Ibama, and an international Amazon Fund was created to pay for conservation projects. But it began ticking up again after a weakening of environmental legislation and budget cuts during Brazil’s recession of 2014-2016. Between August 2017 and July 2018 Brazil lost 7,900km² of Amazon forest—nearly a billion trees. This year’s figure is almost sure to be higher. Preliminary satellite data showed that 920 km² were cleared in June, 88% more than the same month in 2018. In July 2,255 km² were cleared, a startling 278% more than the same month last year (see chart).

Environmentalists blame Mr Bolsonaro’s insouciance about the Amazon. It is a “virgin” that should be “exploited” for agriculture, mining and infrastructure projects, he says. The environment minister, Ricardo Salles, fired 21 of Ibama’s 27 heads; he has yet to replace most of them, crippling the agency’s enforcement duties. In response to increasing alarm about the jump in tree-clearing, Mr Bolsonaro fired the head of the agency that tracks deforestation, called the data “lies” and told a journalist that those concerned about the environment should eat less and “shit every other day.”

The consequences of the destruction of the Amazon rain forest will be severe.

The forest also influences the water cycle on a regional and perhaps even global scale. As moisture comes off the Atlantic Ocean it falls on the forest as rain. This water gets sucked up by deep roots, then moves through plants and across the surface of leaves before returning to the atmosphere. Winds blowing over the uneven forest canopy create turbulence, which allows the atmosphere to absorb more moisture.

All this water then moves like a giant flowing river in the sky, falling as rain and then evaporating again and again until it reaches the Andes. Ultimately, the forest produces at least half of its own rain.

"One water vapor molecule may be recycled five to seven times before it leaves the system, either through the atmosphere or the Amazon River," says Carlos Nobre, a climate scientist with the University of Sao Paulo's Institute for Advanced Studies.

But experts increasingly fear this delicate exchange could collapse. The loss of just a fraction more of this moisture-creating forest could lead far more of it to dry out, which would reduce rainfall even more, in a self-reinforcing spiral. Already, climate change, decades of logging, and land-clearing by intentionally set wildfires have sparked record-setting droughts in 2005, 2010, and 2015-2016.
Even as Bolsonaro prepares to take office, the Amazon is already changing.

The dry season is lengthening and rainfall has dropped by a quarter in some regions. Meanwhile, precipitation, when it comes, sometimes arrives in more intense bursts, leading to massive floods in 2009, 2012, and 2014. The region's climate system is oscillating more wildly.

In the study she led, published in the journal Global Change Biology with more than a hundred other scientists as co-authors, Esquivel-Muelbert found that during the past 30 years, more drought-tolerant plant species have appeared in the Amazon, while species that predominantly emerge in wet areas are declining. Fast-growing trees and taller trees that are better at accessing the sun are outcompeting shorter, damp-loving species.

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Brazil's (and Indonesia's) massive deforestation more than undoes the rest of the world's reforestation efforts.  Sometimes I am convinced that mankind is doomed, thanks to our own greed and stupidity.  And what is it about the extreme right that they are so hostile to facts?