The research provides a positive model for protecting a forest region that is a hub for biodiversity, including serving as a key habitat for endangered chimpanzees. At the same time, it also validates the effectiveness of a "Payments for Ecosystems Services" program of the sort that could bolster the battle against global deforestation and its impact as a leading driver of climate change.
More such programs could be supported under a broader United Nations initiative called REDD+ (Reducing Emissions from Deforestation and Forest Degradation in Developing Countries), in which richer countries and other international funders make payments to developing nations in exchange for protecting their vital trees. That quest that has only become more urgent after an explicit shout-out to the importance of combating deforestation, and REDD+, in the 2015 Paris climate agreement.
In the new study, just published as a working paper by the National Bureau of Economic Research, owners of forested land in 60 villages in the Hoima and Kibaale districts of western Uganda were offered $ 28 per year (70,000 Ugandan shillings) over two years for every hectare of forest that they did not harvest or chop down for other economic reasons. By comparison, in 61 other villages, nothing was offered — but rates of deforestation were monitored by satellite in all villages.
The result was that while forest cover decreased by between 7 and 10 percent in the "control" villages, it only dropped between 2 to 5 percent in the designated "treatment" villages, suggesting that the incentive payments were preventing a significant number of landowners from selling large trees for timber or charcoal, or chopping down forest to grow more crops.
"This study I think of as an important proof of concept that this did have a big impact, and a lot of the money that was being paid was really creating new forest cover that would have disappeared absent the program," said Seema Jayachandran, an economist at Northwestern University who led the research, which was conducted with colleagues from Stanford, the Carnegie Institution for Science and the Porticus Foundation.
The study validates the idea that deforestation can be battled in a cost-effective way, a policy possibility that emerges in part because of vast global economic inequities. This has created a situation where encouraging forest preservation in relatively poorer, developing countries, where forests are often relied on for livelihoods, turns out to be more cost effective.
"In terms of the global impact, we don't care if a tree is kept intact in the U.S. versus in Uganda, but the income someone is getting for that tree in Uganda is less than they're getting in the U.S.," said Jayachandran.
The study estimated that the cost of delaying the emission of a ton of carbon dioxide to the atmosphere under this program was just 57 cents — but the benefit of doing so, based on calculations using the EPA's standard "social cost of carbon" measurement, was $ 1.11.