61% of the world's lost forests can be restored to significantly reduce greenhouse emissions

 Newswise — An international collaboration of scientists with the participation of a RUDN ecologist has for the first time assessed the natural potential of the world's forests to retain carbon. The results can be called hopeful - those regions where forests can still be restored have great potential and will help reduce the amount of greenhouse gases. The results were published in Nature.

The climate crisis threatens ecosystems and humanity. Forests, which contain 80–90% of the Earth's plant biomass, play a key role in mitigating it. Forests absorb carbon emissions, so fewer forests mean more carbon in the atmosphere. To make timely decisions, it is important to know how forest carbon reserves are distributed around the world, where forests can be restored and carbon returned from the atmosphere, and where the ecosystem cannot be restored. However, there is no unambiguous data on this - existing estimates vary several times. An international collaboration of scientists with the participation of an ecologist from RUDN University has compiled the first global map of a forest’s ability to store carbon. 

“Humans have destroyed almost half of the Earth's natural forests. We continue to lose another 0.9–2.3 gigatons of carbon each year—about 15% of annual human carbon dioxide emissions. Environmental initiatives should reduce forest loss. A key step for this is to gain a comprehensive understanding of the global distribution of carbon in forests and the potential of forests to recapture carbon after restoration,” Dmitry Kucher, Ph.D., head of the Scientific Center for Research, Integrated Design and Development of Urban and Agricultural Development of the RUDN University said. 

Scientists used almost all available sources: satellite images, forest inventory data, and ground measurements. Based on these data, the authors built several models. The result was a map of natural “forest potential” - that is, how much carbon a forest could store if there were no anthropogenic influence. 

Despite regional differences, forecasts appeared to be in good agreement globally. The difference between satellite and ground-based estimates was no more than 12%. The world's forests now store 328 gigatons of carbon less than they could. Of this potential, 102 gigatons are in urban areas, cropland, and grassland, where forest restoration is unlikely. However, the remaining potential (226 gigatons) occurs in areas where human influence is less pronounced. Most of this potential (61%) is in forested areas that can recover. This means that reforestation can significantly reduce the amount of carbon in the atmosphere.

“Forests cannot replace emission reductions, but conservation, restoration, and sustainable management make an important contribution to achieving global climate and biodiversity goals,” Dmitry Kucher, Ph.D., head of the Scientific Center for Research, Integrated Design and Development of Urban and Agricultural Development of the RUDN University said.