The Amazon Heats Up Over recent decades, human activity has had a dramatic impact on the global climate and local weather. We've altered the atmosphere, warmed the land and made the ocean hotter, melting ice and raising sea levels. And all of that has happened very quickly. The planet is now heating up two to three times faster than at any time during the last 65 million years. That means that extreme weather events that used to happen once a century happen once a month — or even once a day. A NASA study found that between 1979 and 2013 the Amazon basin has seen a 15 percent increase in wildfires, an 11 percent reduction in forest coverage, and an 80 percent increase in deforestation. According to one study, the total area burned is the same as that burned in the US between 1984 and 1994. Between 2003 and 2013 fires burned over half the total area of the Amazon. [Amazon Fire Season: 7 Ways to Help] The climate change that caused this fire season is not the fault of one person or region, but it's not hard to pick out some causes. Over the past several decades, farmers in Brazil have been pushing deep into the forest to take advantage of the fertile alluvial soils that the rainforest leaves in its wake. This is especially true in the dry season, when a year's worth of rainfall in the forest evaporates, leaving behind the rich minerals. A 2007 study found that the deforestation rate has accelerated as soil has become depleted, making the forest more vulnerable to fire. The result is a long-term drying trend in the Amazon that has been matched by rising temperatures. The Amazon is still wet during the wet season, but warmer temperatures cause storms to be much less intense than they once were. The wet season is shorter and more extreme. [Billion-Dollar Earth: Earth's Top 10 Most Valuable Biomes] Since 1994, average annual precipitation over much of the Amazon basin has decreased by nearly 4 inches per decade. That adds up to a loss of roughly 40 percent of the region's annual precipitation. To put it another way, an area that's wet half the year is now wet for half the time. Over the past few years, scientists have found a link between droughts and tree die-offs in the Amazon. This makes it even easier for the forest to become a tinder box. Warmer temperatures and drier soils have also made the forest more vulnerable to forest fires. The Amazon is currently on fire for almost three months out of every year. A 2013 study found that, by mid-century, the area burned could triple to 200,000 square kilometers (80,000 square miles) every year. This study used the most comprehensive set of climate model simulations yet produced. The simulations were run at the National Center for Atmospheric Research in Boulder, Colo., and combined high-resolution weather and climate models with outputs from 25 different computer models of the Amazon's biosphere. The Amazon fires of this summer are yet another example of the devastating impacts of humans on the Earth's climate, but that doesn't make the task of putting out the fires any easier. The only hope for these fires is a quick recovery from this season's dry spell. Follow us @livescience, Facebook & Google+. Original article on Live Science.