So much of the Earth’s forest has been destroyed that the tropics now emit more carbon than they capture, scientists have found.
Tropical forests previously acted as a vital carbon “sink”, taking carbon from the atmosphere and turning it into oxygen, but the trend has reversed: they now emit almost twice as much carbon as they consume.
Scientists said ending deforestation and degradation in the tropics could reduce global carbon emissions by 8 per cent.
In a paper published in the journal Science, researchers from Boston University and the Woods Hole Research Center said there is a limited window of opportunity to reverse the trend by restoring forested areas. 
They used a new method to assess carbon density, measuring levels not just in areas of complete deforestation but also places where more subtle losses have been caused by forest degradation and disturbance.
Satellite images, laser technology and field measurements were used to record how vast …