Chopping Down Rainforests Could Endanger Energy Supply
Brazil is the third greatest user of hydroelectricity in the world, with 80 percent of its energy coming from this source. The government has invested billions of dollars to build huge hydroelectric plants including one at Belo Monte on the Xingu River in the rainforest. When completed, this $14.4 billion project will have a maximum output of 11,233 megawatts and be the world’s third-largest, behind China’s Three Gorges and Itaipu, on the border between Brazil and Paraguay.
These grand plans are meant to furnish Brazil with a steady supply of power as well as to fill up reservoirs prior to the country’s hosting of the World Cup in 2014, not to mention the 2016 Olympics in Rio de Janeiro. The last thing the country needs is a repeat of the 2001-2002 apagão (“big blackout”) in which electricity was rationed, to the detriment of Brazil’s economy. But a new scientific study suggests that the well-publicized loss of rainforests, whose clearing has occurring in developing the country’s infrastructure, could mean a significant reduction in the amount of energy that hydroelectric projects can provide.
River flow has been observed to increase after trees along streams have been cut down. Without the trees and their roots, the water in the soil goes into streams and rivers, rather than being taken up into the atmosphere. The new research, just published in the Proceedings of the National Academy of Sciences, (PNAS) suggests a different story.
According to researchers from the Amazon Institute for Environmental Research in Brasília, large swaths of tropical rainforest produce rain clouds as the moisture from the trees’ leaves evaporates. In other words, chopping down trees actually decreases rainfall and therefore the amount of water in rivers including the Xingu River where, as you’re reading this, some 20,000 laborers are working round the clock to build Belo Monte. The scientists say that deforestation could mean that as much as 40 percent of the power which Belo Monte is to generate will be lost by 2050.
The PNAS study reveals yet another of the losses to the environment due to the loss of the rainforests. Deforestation contributes to climate change as the numbers of carbon dioxide-absorbing trees disappear. It also threatens the livelihood and the survival of indigenous communities who have faced displacement from their centuries-old homes and the flooding of their reserves.
Many Indian protesters have said they have not been sufficiently included in decisions about projects such as Belo Monte and have launched a legal challenge against its construction. When asked if any hydroelectric power on the Xingu would be all right, Juma Xipaia says in the Economist: “No. It is impossible. For us, the water is everything.”
The Economist also cites a recent survey of of 1,222 Amerindians from 20 tribes across the country who said they wanted what most other Brazilians do: ”better health care and education, sanitation and electricity, more income and jobs.” The hydroelectric power plant at Itaipu was built in the 1970s under the military government then ruling Brazil. While it “destroyed some of the world’s loveliest waterfalls” and also flooded 1,350 square kilometers of land and displaced 10,000 families, it now provides 17 percent of Brazil’s electricity and 73 percent of Paraguay’s. While it is smaller than the massive plant China built at the Three Gorges (which also led to the displacement of many from farmlands), Itaipu is said to be “highly efficient” and provides more energy.
The authors of the PNAS study note that their findings go against “conventional wisdom.” The Brazilian government is moving ahead with a plan to build a total of 48 dams, with Belo Monte one of 30 planned in the rainforest. But if more research shows how necessary trees are for producing the water powering hydroelectric energy plants, Brazil could find itself without rainforests but with huge and idle structures built to harness the power of rivers that, after the trees are cut down, have dried up.
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