In addition to the loss of habitat, trees, and the carbon dioxide reservoir, cutting down rainforests can have other unintended consequences. Unfortunately, the Amazon rainforest may have shrunk to the point where it can no longer produce enough rainfall for southern areas of Brazil. This is an ecological disaster in the making, and here’s how it’s happening…
The Amazon rainforest generates about 20 billion tons of water vapor each day from its 1.4 billion acres of trees. To put this into context, that’s about the same amount of water that flows out of the Amazon River each day. Removing a substantial portion of this water from the ecosystem naturally has consequences, and drought is one of them.
The vibrant city of São Paulo is the largest in Brazil, with around 21 million people in its metro area; naturally, it requires a phenomenal amount of water. According to Antonio Nobre, a respected Earth scientist, the mass destruction of the Amazon rainforest is causing the current drought in that area.
There are also natural processes that are compounding to the drought problem in the Amazon.
When trees absorb water from the ground, they transfer it to the leaves; this water then evaporates, creating humongous quantities of water vapor. This process is known as transpiration. In addition, tree roots keep the soil stable and slow down the process of water running off into the river. Without these trees, water runs directly into the river and is carried directly out to sea.
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In addition to water, the sheer amount of water vapor produced by the Amazon rainforest has to go somewhere, and it tends to head south due to prevailing wind currents. If less water vapor is produced, less rain falls; this would cause a drought somewhere in the south of South America.
Because São Paulo is at the end of the Tiete River – which runs directly south of the Amazon basin – any fall in volume in the rainfall upstream makes itself known quite quickly. There are two dams along the Tiete River; falls in water volume mean that they produce less hydroelectric power, which leads to an increased use of fossil fuels or rolling blackouts.
Other effects are even less subtle,
such as less water for crops and increased reliance on food produced in the Amazon basin, which leads to increased rainforest clearance, which perpetuates the cycle. Of course, people also need water to survive, and a general lack of water in this rather warm country means that thousands, if not millions, could die from the drought.
Another cause comes from thousands of miles away – by the American thirst for beef. Millions of acres of the Amazon are chopped down each year to make way for beef ranches and soybean plantations, and it’s going to get worse as the U.S. Department of Agriculture now allows fresh beef to come in from Brazil and Argentina. This may well lead to a spike in demand and further pressure on the rainforest.
So how can you stop this?
The answer isn’t particularly radical, surprisingly. A reduction in beef consumption, including beef produced for fast food, would help to reduce beef prices. If it is not economical to produce beef, Brazilian ranchers will not be able to produce it. If you do choose to buy beef, make sure you know where it is from; buy local whenever you can. If everyone makes small changes in their buying habits and their diets, it’s possible to make a big difference and help protect the Amazon rainforest.