July 24, 2024
Nearly half of all viable tree-planting locations would be more cost-effective at reducing emissions if forests were restored using a “natural regeneration” approach
ARLINGTON, Va. (July 24, 2024) – A first-of-its-kind study, published today in the scientific journal Nature Climate Change, offers a deeper understanding of reforestation as a climate strategy – its climate mitigation potential and the most-cost-effective methods to pursue in different locations. The study finds that there is up to 10 times more low-cost, carbon removal potential from well-planned reforestation projects than previous official estimates suggested. In many areas, this potential remains untapped.
As countries work toward meeting their Paris Agreement targets to keep global warming within 1.5 degrees Celsius, this research can provide guidance on the most cost-effective type of reforestation for a given location or situation – information that could prove useful given recent estimates that the level of investment in nature-based solutions needs to triple by 2030 to achieve the Paris climate targets.
Reforestation – the restoration of tree cover to areas that have been deforested – is a Natural Climate Solution that has been identified by the Intergovernmental Panel on Climate Change (IPCC) as a mitigation option with high potential. And yet, much of the estimated costs of reforestation have, until now, been based only on theoretical modeling and projections.
This study is the first to calculate the cost-per-ton of reforestation (how much carbon can be removed from the atmosphere at a given cost) by compiling data on actual costs from reforestation projects across low- and middle-income countries.
Reforestation methods often entail planting new trees of a single species, to refill the land that was previously deforested. However, researchers found that, for 46% of forests, allowing trees to regrow naturally would sequester more carbon at lower cost. Natural regeneration allows the deforested land to regrow on its own, with human intervention only needed to keep the area protected from additional damage as it recovers.
“We found that natural regeneration is more cost-effective at reducing emissions in almost half of forests, meaning that this more biodiverse method of reforestation is vastly underutilized,” said Jonah Busch, the lead author of the study who conducted the research during his Climate Economics Fellowship at Conservation International. “If everyone only reforested across the world with one method, we’d miss out on the climate benefits of a more varied approach.”
Researchers found that using a mix of the two reforestation methods would remove about 40% more carbon (44% more than natural regeneration, 39% more than tree-planting) than either one alone. The research created five unique spatial datasets that were combined to show the most cost-effective reforestation method, cell-by-cell.
Reforestation projects with an estimated cost-per-ton below USD$ 20 are considered low-cost options. The study finds that there is an opportunity for 10 times more carbon removal from low-cost reforestation projects than previous IPCC estimates indicated.
“The opportunity for low-cost reforestation appears much more plentiful than previously thought; this suggests reforestation projects are worth a second look by communities that might have prejudged them to be cost prohibitive,” said Busch. “While reforestation can’t be the only solution to climate change, our findings suggest it should be a bigger piece of the puzzle than previously thought.”
Reforestation is a relatively accessible and affordable way to remove carbon from the atmosphere. It’s for this reason that reforestation factors so heavily into the guidelines and recommendation of the global Sustainable Development Goals (SDGs), international social and environmental benchmarks set by the United Nations – particularly SDG 15, “Life on land.”
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Quote Bank
“Between now and 2030, natural climate solutions, such as reforestation, represent the most feasible and cost-effective way to reach gigatons of carbon removal the IPCC has identified as needed to reach Paris Targets. By providing actionable guidance on where and how to reforest, we hope our work will spur public and private actors to increase the speed and scale of this critical climate solution.” – Matthew Potts, professor and S.J. Hall Chair in Forest Economics at the University of California, Berkeley
“Our results illustrate that a mix of planted and naturally regenerated forests is often the best way to balance society’s demands on forests. Carbon payments can provide a sufficient reforestation incentive on their own in some places, while the net cost of carbon sequestration can be reduced in other places by earning income from sustainable wood harvests.” – Jeff Vincent, professor of forest economics and management at Duke University’s Nicholas School of the Environment
“Generally speaking, we can let forests regenerate on their own, which is slow but cheap, or take a more active approach and plant them, which speeds up growth but is more expensive. Our study compares these two approaches across reforestable landscapes in low- and middle-income countries, identifying where naturally regenerating or planting forests is likely to make more sense. If your objective is to sequester carbon as quickly and as cheaply as possible, the best option is a mix of both naturally regenerating forests and planting forest.” – Jacob Bukoski, assistant professor at Oregon State University’s College of Forestry
“We have limited time and resources to tackle climate and deploy reforestation at scale. This work helps to pinpoint both the places and the methods where you can get the greatest carbon returns per hectare of investment at the lowest costs. It also shines further light on the potential for letting nature grow as a powerful climate solution.” – Susan Cook-Patton, senior forest restoration scientist at The Nature Conservancy
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About Conservation International: Conservation International protects nature for the benefit of humanity. Through science, policy, fieldwork and finance, we spotlight and secure the most important places in nature for the climate, for biodiversity and for people. With offices in 30 countries and projects in more than 100 countries, Conservation International partners with governments, companies, civil society, Indigenous peoples and local communities to help people and nature thrive together. Go to Conservation.org for more, and follow our work on Conservation News, Facebook, Twitter, TikTok, Instagram and YouTube.