The temperature benefits resulting from realistic efforts to replace cropland with forests are small, according to a study published online in Nature Geoscience. The researchers conclude that afforestation is not a substitute for reducing greenhouse gas emissions.

The United Nations considers the conversion of croplands or marginal lands into forests — known as afforestation — as one of the key climate change mitigation strategies available to governments.

Vivek Arora and Alvaro Montenegro used an Earth system numerical model to examine the potential of five afforestation scenarios to reduce warming between 2081 and 2100. They found the temperature benefits would be minimal; even the unrealistic scenario of converting 100% of the area now occupied by croplands to forest reduces warming by only around 0.45 ℃.