(CNN) -- The loss of native tropical forests accounts for more than 10% of the carbon emissions responsible for the changing climate, receiving much-deserved attention at the recent U.N. climate change conference in
When forests are cleared and burned, the carbon contained in the trees and other vegetation -- roughly half of their dry weight -- is released into the atmosphere as carbon dioxide, the main greenhouse gas contributing to global warming. Most of the carbon dioxide emissions caused by human activity come from fossil fuels. But native tropical forests average about 150 tons of carbon per hectare, and millions of hectares are cleared and burned every year.
Over the past decade, governments and industry have responded to growing pressure to reverse deforestation, sometimes committing to reducing it to zero. But with few exceptions, we've lacked the tools to assess accountability.
This changed when Science magazine published a groundbreaking analysis of annual deforestation on the entire planet between 2000 and 2012. With the help of Google Earth and using advanced computing techniques,
professor Matthew Hansen and his colleagues analyzed unprecedented amounts of
satellite imagery at a 30-meter scale. Their work allows anyone with a computer, tablet or
smartphone and a decent Internet connection to see clearly where the world's
forests are growing and where they are being destroyed. University of Maryland
Go to Global Forest Change and click on different regions. Use the pulldown menu to see the state of forests all over the world from 2000 to 2012, using several measurements. Go to the damage locations like the swath of the
Siberian forest fires, palm oil plantations in Borneo,
and many more. Distant regions are close at hand, the range of forests becomes
easy to grasp, and the speed at which many of the forests are vanishing grows
far more difficult to ignore.
More than 60 governments have signed on to the World Wildlife Fund's pledge to achieve "zero net deforestation" by 2020. The pledge specifically excludes offsetting native forest loss with tree plantations, although regrowing forests on abandoned lands can be subtracted from any "gross" deforestation.
With the new digitized maps and data available online, civil society watchdogs can and should hold governments accountable for making progress toward their targets. read more: