The Impact of Climate Change on the Amazon

For many, the Amazon evokes images of dense rainforests full of diverse plant and animal life. It is a place of wonder and mystery. Unfortunately, the Amazon is quickly becoming a place threatened by global warming and an ever changing world climate.

According to a report to the World Wildlife Fund for Nature entitled "The Amazon's Vicious Cycles" by Daniel C. Nepstad, the Amazon greatly impacts climate "by acting as a giant consumer of heat close to the ground, absorbing half of the solar energy that reaches it through the evaporation of water from its leaves."

This means that the Amazon actually helps reduce the amount of solar energy by acting as a giant air conditioner. Essentially, this energy is transformed through the evaporation of huge amounts of water from the forest's leaves and other surfaces. This process in crucial because it produces the clouds that sustain the forest with rainfall.

The Amazon also plays a vitally important role as a storehouse of carbon, which many of you know is a main contributor to global warming through its release into the atmosphere as carbon dioxide. Trees in the Amazon, according to Nepstad, contain 90-140 billion tons of carbon. This is equivalent "to 9 to 14 years of current global, annual, human induced carbon emissions - estimated in 2007 at approximately 10 billion tonnes per year".

Right now, carbon is leaking out of the Amazon rainforest at a rate of 0.2 to 0.3 billion tons per year. This rapid release of carbon is due to large portions of the rainforest being converted for use as cattle pastures or other agriculture means. The amount of carbon being released into the atmosphere can double when severe drought increases the risks of forest fires.

Images courtesy of panda.org The Amazon's Vicious Cycles

"When all Amazon countries are combined, carbon emissions from this region may reach 0.4 to 0.5 billion tonnes per year even without considering emissions from forest fire", Nepstad writes.

Many of you know that the forests of the Amazon are highly resistant to fire. Over the past 2 millennia, the Amazon forest would burn regularly at 400-700 year intervals during periods of drought. Today, with human transformation of the forest landscape, the periods between first has shortened dramatically. Instead of catching fire every century or so, some forest are catching fire every 5-15 years! Every time the forest burns, it becomes more and more susceptible to frequent fires.

So what does climate change mean to the future of the Amazon? For several decades, teams of scientists have worked on computer models to answer this very question. According to these models, the Amazon is heading towards a drier, warmer future. Nepstad says, "Counteracting these trends are emerging changes in landholder behavior, recent successes in establishing large blocks of protected areas in active agricultural frontiers, important market trends favoring forest stewardship, and a possible new international mechanism for compensating tropical nations for their progress in forest conservation, that could reduce the likelihood of a large-scale dieback of the Amazon forest complex."

It would appear that efforts are being made to protect the Amazon region from declining completely. However, avoiding this scenario, according to Nepstad, may depend on substantial global reductions in greenhouse gas emissions.