Storing carbon through tree planting, preservation costs more than thought

Dec. 1 (UPI) -- Planting trees and protecting forests are two of the myriad strategies for keeping carbon out of the atmosphere.

Of all the options, they're considered the most eco-friendly, or greenest, but new research suggests planting and protecting trees does come with costs -- and those costs are quite a bit larger than has been previously estimated.

According to a new study, published Tuesday in the journal Nature Communications, planting trees and conserving forests could reduce carbon dioxide emissions by as much 6 gigatons a year between 2025 and 2055.

Researchers calculated the reductions would come with an annual price tag of $393 billion.

"There is a significant amount of carbon that can be sequestered through forests, but these costs aren't zero," study co-author Brent Sohngen, professor of environmental economics at the Ohio State University, said in a news release.

According to Sohngen and his colleagues, previous studies looking at the role of forest conservation in the global effort to curb climate change have largely ignored the effects on forest land use, management and trade.

The new analysis showed protecting existing forests is a more cost effective way to curb carbon emissions than planting new trees.

In places where forest harvesting is an essential economic activity, the study's authors suggest changes to how and when trees are harvested -- as opposed to total protection -- could offer a more cost-effective strategy for carbon reductions.

Sohngen and company determined forest protection measures are likely to deliver the most bang for their buck in Brazil, the Democratic Republic of Congo and Indonesia.

Unlike previous studies that have attempted to audit the economic impacts of various carbon sequestration, the latest calculus accounted for what researchers call "carbon leakage."

When trees are planted on agricultural lands in one part of the world, researchers suggest market demands can trigger deforestation in other parts of the world.

The study's authors are in agreement with the broader scientific community that carbon emissions must be significantly reduced to avoid catastrophic climate impacts. However, they suggest more work must be done to identify the most cost-effective strategies for curbing emissions.

"Until now, there has been limited research investigating the costs of climate change mitigation from forests," said lead study author Kemen Austin.

"Better understanding the costs of mitigation from global forests will help us to prioritize resources and inform the design of more efficient mitigation policies," said Austin, a senior policy analyst with RTI International, a nonprofit research institute based in North Carolina.

Planting and protecting trees alone, however, won't be enough to prevent catastrophic climate change, researchers said. Efforts to conserve forests must be accompanied by robust efforts to scale green energy, like solar and wind power.

"What we see is that you should devote about a third of your effort to this stuff and two-thirds to the other stuff -- to reducing coal, to investing in solar, to switching to electric," Sohngen said. "If you want your total mitigation to be as cheap as possible, that's what you would do."