The main reason is agriculture. All the nutrient-richness is locked up in the forests themselves, so once they are burned and the nutrients from their ashes are used up, farmers are left with utterly useless soil.
So on they go to the next patch of forest: raze, plant, deplete, repeat. All told, agriculture is responsible for at least 80 percent of tropical deforestation.
Not surprisingly, agriculture causes emissions, too—in fact, farm emissions are second only to those of the energy sector in the dubious contest for the emissions title. In , farms were responsible for about 13 percent of total global emissions. Most farm-related emissions come in the form of methane cattle belching and nitrous oxide from fertilizers and the like. The uptick in mosquito-borne diseases, for example, or the rapid spread of roya, an insidious plant disease that threatens our supply of coffee are all indirect consequences of deforestation and global warming.
Dear EarthTalk : Is it true that cutting and burning trees adds more global warming pollution to the atmosphere than all the cars and trucks in the world combined? According to the World Carfree Network WCN , cars and trucks account for about 14 percent of global carbon emissions, while most analysts attribute upwards of 15 percent to deforestation.
The reason that logging is so bad for the climate is that when trees are felled they release the carbon they are storing into the atmosphere, where it mingles with greenhouse gases from other sources and contributes to global warming accordingly. The upshot is that we should be doing as much to prevent deforestation as we are to increase fuel efficiency and reduce automobile usage.
According to the Environmental Defense Fund EDF , a leading green group, 32 million acres of tropical rainforest were cut down each year between and —and the pace of deforestation is only increasing. REDD essentially works to establish incentives for the people who care for the forest to manage it sustainably while still being able to benefit economically.
Examples include using less land and therefore cutting fewer trees for activities such as coffee growing and meat and milk production. But until recently, no had attempted to understand that balance. Rain now falls in massive bursts more frequently than it once did, triggering record floods. Droughts come more often and, in some areas, last longer.
Trees that fare better in wet places are being outcompeted by tall, drought-tolerant species. Illegally set fires are on the rise again.
About 5. So, in , the National Geographic Society brought Covey, Soper, and a team of other Amazon experts together to begin trying to dissect how all of these pieces fit together. Resource extraction, damming rivers, and the conversion of forest for soybean and livestock production all alter the natural systems in a variety of ways. But most serve to warm the climate. Methane is a particularly important player. Humans have diminished that capacity. Rob Jackson , an earth systems scientist at Stanford University and a leading expert on global greenhouse emissions, considers the new research a worthwhile contribution.
Patrick Megonigal , associate director of research at the Smithsonian Environmental Research Center, agreed. When you consider the whole cast of other characters, the outlook in the Amazon is that the impacts of human activities will be worse than we realize. Many questions remain. The biggest for Megonigal is one that Lovejoy also worries about: How do all of these factors influence the local Amazon climate?
The duo believes that tipping point could be reached if as little as 20 to 25 percent of the rainforest is cleared. What happens in Brazil and neighboring countries in the Amazon affects the whole world.
They urged Biden to use trade with the U. When fossil fuels are burned, carbon from dead and decayed plants, animals and phytoplankton that lived hundreds of millions of years ago before dinosaurs existed , is released into the atmosphere in the form of carbon dioxide.
Haze from forest fires blankets a an area of deforestation. Burning fossil fuels, in combination with destruction of carbon sinks due to deforestation and other activities, has contributed to more and more carbon dioxide building up in the atmosphere — more than can be absorbed from existing carbon sinks such as forests.
The build-up of carbon dioxide in the atmosphere is driving global warming, as it traps heat in the lower atmosphere. Carbon dioxide levels are now at their highest in human history.
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