Purdue researchers propose way to incorporate deforestation into climate change treaty

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The approach, titled "Preservation Pathway," would provide carbon credits for developing countries that both set aside a portion of existing forests and slow the rate at which the remaining forests are cut down.

A key point in the approach is its call for a deceleration of deforestation, Gurney said.

"Deceleration - continuously reducing the rate of deforestation - is the only way to ultimately reach zero," he said. "A fixed reduction or decline in deforestation will only delay complete forest destruction."

Gurney applied the idea of deceleration to the common chore of mowing a lawn.

"You could slow down the lawn mower, but it would still eventually cut down all of the grass," he said. "You have to continue to slow down at each turn until you hit the point where the mower is not moving. That's the only way to leave some uncut grass."

Tropical deforestation currently accounts for roughly one-fifth of the global emissions of carbon dioxide, the most important human-derived greenhouse gas, Gurney said.

"This approach brings together the two main goals being discussed in international climate change policy: preserving existing forest and reducing deforestation," said Gurney, who is an assistant professor in the departments of Earth and Atmospheric Science and Agronomy. "It also provides an incentive for developing countries to join in the Kyoto Treaty because they can sell the carbon credits they earn. Many developed countries will need to purchase credits to meet the greenhouse gas emissions reductions currently being discussed. Forests are a major resource for developing countries. We must compensate them fairly for the value of this resource."

Unlike fossil fuel emissions' effect on climate, deforestation is poorly understood, Gurney said.

"The issue of deforestation is very complicated," he said. "We are not only concerned with the carbon emitted into the atmosphere when trees are cut down, but also with preserving forests because they provide food, medicine and a natural habitat."

Gurney and co-author Leigh Raymond, a Purdue associate professor of political science, detailed the Preservation Pathway approach in a paper that was published March 24 in the journal Carbon Balance and Management.

Raymond, who also is an associate director of Purdue's Climate Change Research Center, said the approach allows countries to choose what will work for them and provides an incentive for participation.

"The Preservation Pathway allows countries to select how much of the existing forest it will save," he said. "The greater the amount of forest preserved, the more credits the country earns. A country must also show a deceleration in deforestation of forest not set aside."

Raymond said the paper is a commentary to start discussion on the policy recommendation.

"Carbon emissions and stored carbon are the two big issues of climate change policy," he said. "The big question is how to deal with stored carbon in forests. Should a country get credit for the forests that exist on its land? Is that fair?"

The ultimate goal of the Kyoto treaty is to have the whole world involved and actively working to reduce emissions that cause climate change, he said.

"The emissions and practices of one country affect the entire world," Raymond said. "We must get the developing countries on board. This approach enables that and also opens up the credit trading system. This will help the developed countries obtain the carbon credits they need and will improve the success of policies because more players are involved."

Gurney said the approach has technical advantages over current proposed deforestation policies that would create a baseline and compare deforestation rates relative to it.

"The baseline approach would use historical data and projections of the future, which is technically very difficult to do," Gurney said. "We have a poor understanding and limited historical data on deforestation rates, and predicting what the baseline may be in the future is always iffy."

The Preservation Pathway approach would use satellite imagery to measure success.

Satellites could be used to monitor the forests' canopy cover, which allows for measurement of relative change from one year to the next.

"The Preservation Pathway would only require a relative rate of change and not precise measurements," Gurney said. "It is extremely difficult to reliably measure the emissions from large forest expanses. To accomplish that would require someone on the ground taking measurements, and there are tropical forests where few people have ever set foot.

"This approach relies on the tools we have now and what we know, and it avoids what we don't know," he said. "It gets around some of the technical problems and scientific uncertainties that often slow policy-making."

Next, the research team will evaluate details of the proposed policy. The team will use specific countries as examples and will evaluate various aspects of the approach, including to what degree a satellite can evaluate deforestation rates and what amount of money would be sufficient compensation for the earned credits.

"This approach is a path between now and the end of deforestation," Gurney said. "It does not dictate a percentage rate drop over a set period of time. It is a path all the way to the end, and each can take the path at their own pace."

Purdue University