Satellites provide more consistent data, indicating lower CO2 emissions levels from deforestation -- study

Tiffany Stecker, E&E reporter
Published: Friday, June 22, 2012

Carbon emissions figures from deforestation could be half to three-quarters lower than previous estimates, according to new estimates that rely on satellite data.

The researchers from Winrock International, the World Bank, the California Institute of Technology's Jet Propulsion Laboratory, Applied GeoSolutions and the University of Maryland found that 810 million metric tons of carbon dioxide per year was released between 2000 and 2005 as a result of deforestation -- only
25 to 50 percent of recently published estimates. The study was published in Science yesterday.

This means carbon emissions from deforestation account for only 7 to 14 percent of total greenhouse gases from human activity. The level that is generally given for deforestation emissions is around 20 percent. This is the first study to rely exclusively on satellite data from NASA, leaving out the deforestation numbers that countries submit regularly to the U.N. Food and Agriculture Organization (FAO).

The methods used to collect the FAO data are inconsistent across the world and often outdated, leaving highly uncertain numbers for deforestation emissions, said Nancy Harris, lead author of the report and carbon and a land-use specialist with Winrock International.

"The methods used to report those numbers are all over the place," Harris added.

The novelty of this study, said co-author Alexander Lotsch, is that it is one of the first to use consistent methods and data across all tropical countries.

A better benchmark for difficult negotiations

Countries could use this study as a first benchmark, to be refined further down the road using similar sets of data, added Lotsch, a senior carbon finance specialist with the World Bank's Forest Carbon Partnership Facility.

The data have important implications for REDD+, or Reducing Emissions from Deforestation and Forest Degradation, an international system to pay landowners not to cut down forests. Negotiators at the recent U.N. Framework Convention on Climate Change meeting in Bonn, Germany, began to set guidelines for monitoring and reporting forest carbon losses, in order to provide a uniform system across the world. The parties agreed to push the discussion for guidance to the annual climate conference in Doha, Qatar, this December (ClimateWire, May 29).

These measurements are essential for setting levels on which reductions in deforestation will be measured -- and eventually offering a number to international bodies to decide how much forest owners will be paid. One of the biggest barriers to REDD+ is the inconsistent and outdated methods many forest- holding countries use to report tree density.

The study found Indonesia and Brazil to be -- not surprisingly -- among the highest emitters from deforestation, accounting for 55 percent of total emissions from tropical deforestation.

About 40 percent of the losses were concentrated in the dry tropics with less soil moisture-- areas like east and southern Africa and southern Brazil. These losses accounted for only 17 percent of total carbon emissions.

After an aggressive pace of deforestation in the 1990s, land clearing began to slow down in the first half of the 2000s. At the same time, satellite imagery to track forest biomass was becoming more sophisticated.

Today, rates of deforestation in Brazil are dropping. Forests are growing in China, and India has maintained its forest cover despite economic pressures.

"Globally, there is a picture emerging that is relatively positive," said Lotsch.

Reprinted from ClimateWire with permission from Environment & Energy Publishing, LLC. www.eenews.net. 202-628-6500

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