13 July 2016
by Annette Kirk and Nanci Bompey
Planting new forests could contribute more to the mitigation of climate change than previously thought, according to a new study in Geophysical Research Letters, a journal of the American Geophysical Union.
Land use changes strongly affect the exchange of carbon between the atmosphere and the land. As a result, extending the world’s forest cover has been frequently suggested as a way to increase terrestrial carbon sinks and reduce global warming. Previous research has examined the effects of planting new forests under present day environmental conditions, but it has neglected future changes in climate and carbon dioxide, according to the scientists at the Max Planck Institute for Meteorology who authored the new study. The side effects of increasing forest cover on energy and water fluxes are also not well understood. For example, increased forest cover is darker, which has a warming effect, but a higher leaf area can lead to more water evaporation, which has a cooling effect.
In the new study, the authors modeled the potential climate effects of increasing forest cover under a future high carbon dioxide emission scenario. They find that the carbon sequestration potential of intense reforestation is higher than previous estimates. This is due to the combined effect of land use changes and the enhanced carbon uptake of the terrestrial biosphere in a warm and high carbon dioxide climate, according to the new study.
In their simulations, reforestation leads to a slight reduction in global warming by the end of the century compared to a scenario that includes deforestation. The largest annual mean warming reductions are found in sparsely populated areas, indicating that adaptation to global warming in large regions of the world will still be needed. But the results also suggest that the reduction of temperature extremes can reduce the need for adaptation in some regions.
—Annette Kirk is head of communications at the Max Planck Institute for Meteorology. Nanci Bompey is AGU’s public information manager. This post originally appeared as a news release on the Max Planck Institute for Meteorology website.