The world has lost almost six Californias worth of forest since 2000

Deforestation at this scale is having a tremendous ecological impact, on both species and climate. From 2000 to 2011, deforestation effectively added 14.5 billion tonnes (16 billion tons) of carbon to the atmosphere, about 13% of the world’s total contribution to climate change.
 
But good data on worldwide forest loss are hard to come by. Many countries report deforestation on their own soil, but define it in differing ways. In Canada, if a stand of trees is cut down, but the stumps aren’t removed, government scientists do not consider it a loss, because the forest will eventually grow back. A similar definition holds in Indonesia, but not in other countries. This makes it impossible to stitch together a consistent global picture from national figures.