The big picture: tropical forest lossJune 19, 2009
The vast tropical forests of the Amazon and Congo Basins, as well as those in Indonesia, represent the bulk of tropical forest threatened by deforestation. But how important are forests in other countries to climate change mitigation?
The Terrestrial Carbon Group (TCG) has completed several studies analyzing where forests are most threatened and likely to be lost — and how this will intensify global climate change. They use spatial and economic models, based on global forest cover maps from the United Nations Environmental Programme’s World Conservation Monitoring Centre to help us understand the dimensions of forest loss and climate change.
Incredibly, the TCG model predicts that 10 countries alone would account for 66 percent of all the greenhouse gas emissions through deforestation. That’s right — 10 countries represent two-thirds of all likely carbon dioxide emissions from forests.
How much forest is at risk of conversion and why? To find out, TCG analyzed three layers of data and global forest cover maps. They included the following.
1. All areas effectively protected by law (hectares of parks adjusted by index of governance). TCG concluded that as much as 81 percent of tropical forest is not effectively protected by law, and is therefore subject to deforestation.
2. All areas not suitable biophysically for agriculture (the “very marginal,” “marginal,” or “moderate” locations). The study determined that 85 percent of tropical forest is suitable for agriculture, and is therefore subject to deforestation.
3. All areas not feasible economically to deforest (crops would grow, but not worth the investment). TCG estimated that 79 percent of tropical forest is suitable for agriculture and is economically feasible to deforest, and is therefore subject to deforestation.
Considering all of these factors, TCG says nearly 63 percent of tropical forest is at risk of deforestation if we continue with business as usual, rather than creating the mechanisms and incentives necessary to stop deforestation. This amounts to approximately 175 billion tons of greenhouse gas emissions from more than 2.1 billion acres (868 million hectares) of forest, which at average rates of deforestation (29 million acres — or 12 million hectares — per year) will be gone in about 70 years. That’s less than the average life span for a child born in the United States today.
One hundred and seventy-five billion tons emitted over 70 years equates to about 82 parts per million of greenhouse gas emissions into the atmosphere. That means deforestation alone would increase global temperatures by about two degrees Celsius before the end of the century.
For more information, see TCG’s excellent policy briefs, which go beyond this modeling to suggest why and how we need to set tough reference emission levels to maintain and protect forest carbon.