Although the levels in increased atmospheric carbon dioxide (CO2) as a direct outcome of the burning of fossil fuels have been extensively studied, the amount of CO2 produced as a direct result of tropical deforestation has been inadequately examined. In fact, emissions that are a direct result of anthropogenic land-use modifications represent the most ambiguous and under-studied of that set of human activities that impact the planetary carbon cycle.
There are many factors that make this avenue of investigation particularly challenging. They include the following:
- An assessment of the rates of deforestation in relation to the amount of carbon contained within soils and vegetation
- The methodology used in clearing carbon and the fate of the cleared material
- The response of the soil-based carbon pool to the deforestation
- The longer term impact of the drastic modification of land cover that results from tropical deforestation.
In order to more effectively quantitate the carbon emissions that are a direct result of tropical deforestation, Dr. Nancy L. Harris and her colleagues at the Ecosystem Services Unit of Winrock International in Arlington Virginia used satellite observations of the loss of forest cover and mapped forest carbon stocks. With these tools and methodologies, this group was able to estimate gross carbon emissions in targeted tropical regions between the years 2000 and 2005.
The result they obtained from this systematic approach was 0.81 petagrams of carbon emissions per year – a petagram is equivalent to 1000 trillion grams. This value corresponds to ~ 1.8 trillion pounds of carbon emissions per year. The authors of this study believe that their approach serves as a much more reliable model for estimating global progress on curbing CO2 emissions from deforestation.