Leading climate scientists from Brazil, Australia, and Europe urge rewilding farmland back to forest land in tropical regions to mitigate climate crises. Restoring degraded natural lands would store vast amounts of CO2 while avoiding biodiversity loss and species extinctions. But there’s more to it than merely planting as many trees as possible. Their modeling suggests that the location of the land being restored matters too.
Lead author Bernardo Strassburg said:
“If you plant trees in areas where forests did not previously exist, it will mitigate climate change but at the expense of biodiversity.”
Strassburg and his colleagues at Brazil’s Pontifical Catholic University found that 465 gigatons of carbon dioxide could be removed from the atmosphere by returning 30% of the farmland in several vital areas worldwide and protecting the rest still in good condition. That’s around 50% of the total rise in greenhouse gas since the Industrial Revolution. The transformation would also prevent approximately 70% of predicted species extinctions.
Strassburg said:
“There is a well-known ecological relation between how much a species has lost of its original range and the probability of extinction. As habitat is restored, the probability of extinction is reduced.”
The team identified several of the critical areas where interventions would be most effective. Coastal wetlands and upland peat were included in addition to forests. The coastal regions of West Africa, Brazil, and much of Southeast Asia were high-priority areas, but hotspots were identified on every continent.
Strassburg said:
“Restoring nature did not have to be at the expense of agriculture and food production. If restoration is not properly planned, it could lead to a risk to agriculture and the food sector, but it can increase agricultural productivity if done properly. We can produce enough food for the world and restore 55% of our current farmland with a sustainable intensification of farming.”
Of the 2870 million hectares of farmland the scientists analyzed, around 54% had initially been forest, 25% grassland, and the rest shrubland, arid land, or wetland. They evaluated the land types according to animal habitat, the cost-effectiveness of conversion to their original state, and carbon storage potential. Areas that were optimal for all three criteria were designated the highest priority. The study also included maps of the geographic distribution of over 22,000 animal species to analyze biodiversity effects.
Strassburg said:
“We were surprised by the magnitude of what we found – the huge difference that restoration can make. Most of the priority areas are concentrated in developing countries, which can be a challenge but also means they are often more cost-effective to restore.”
Nature restoration accounts for only about 1% of the global finance devoted to the climate crisis. However, nature-based solutions are among the cheapest methods of storing CO2 and carry the additional benefit of protecting wildlife.
Nathalie Pettorelli, a Zoological Society of London senior research fellow who was not involved in the study, said:
“This paper provides further scientific evidence that ecological restoration is a sensible and financially viable solution to address the global climate and biodiversity crises. However, how ecosystems will be restored is as important as where and how much will be restored. Ensuring that the best science is used to make decisions about how to restore each local ecosystem will be key.”
Alexander Lees, Manchester Metropolitan University’s senior lecturer in biodiversity, who was also not involved with the research, said:
“[This] analysis indicates that we can take massive strides towards mitigating the loss of species and increasing atmospheric carbon dioxide by restoring just 15% of converted lands. The global community needs to commit to this pact to give back to nature post-haste – it’s the deal of the century, and like most good deals available for a limited time only.”
This study focused on land-based restoration, but the oceans can also help mitigate climate change. Swansea University’s senior lecturer in marine biology, Richard Unsworth, who is director of an initiative that restores vital marine habitats called Project Seagrass, said:
“The study focused on land, but the oceans also offer vast benefits linked to biodiversity and opportunities for absorbing carbon dioxide and mitigating climate change. Marine habitat restoration is also vital for our planet and arguably more urgent given the rapid degradation and loss of marine ecosystems. We need restored ocean habitats such as seagrass and oysters to help promote biodiversity but also to help secure future food supply through fisheries, and lock up carbon from our atmosphere.”
Rewilding, wherever it takes place, would require international cooperation. If national borders pose a constraint to efforts, then the biodiversity and climate benefits could drop dramatically.
