Restoring degraded environments, such as by planting trees, is often touted as a solution to the climate crisis. But our new research shows this, while important, is no substitute for preventing fossil fuel emissions to limit global warming. We calculated the maximum potential for responsible nature restoration to absorb carbon dioxide in the atmosphere. And we found that, combined with ending deforestation by 2030, this could reduce global warming 0.18 degrees Celsius by 2100. In comparison, current pledges from countries put us on track for 1.9-2 degrees Celsius. This is far from what’s needed to mitigate the catastrophic impacts of climate change, and is well above the 1.5 degrees Celsius goal of the Paris Agreement. And it pours cold water on the idea we can offset our way out of ongoing global warming. The priority remains rapidly phasing out fossil fuels, which have contributed 86 percent of all CO2 emissions in the past decade.

Deforestation must also end, with land use, deforestation and forest degradation contributing 11 percent of global emissions. Growing commitments to net-zero climate targets have seen an increasing focus on nature restoration to remove CO2 from the atmosphere, based on claims nature can provide over one-third of climate mitigation needed by 2030. However, the term “nature restoration” often encompasses a wide range of activities, some of which actually degrade nature. This includes monoculture tree plantations, which destroy biodiversity, increase pollution and remove land available for food production. Indeed, we find the hype around nature restoration tends to obscure the importance of restoring degraded landscapes, and conserving existing forests and other ecosystems already storing carbon. This is why we applied a “responsible development” framework to nature restoration for our study. Broadly, this means restoration activities must follow ecological principles, respect land rights and minimise changes to land use.

This requires differentiating between activities that restore degraded lands and forests (such as ending native forest harvest or increasing vegetation in grazing lands), compared to planting a new forest. The distinction matters. Creating new tree plantations means changing the way land is used. This presents risks to biodiversity and has potential trade-offs, such as removing important farmland. On the other hand, restoring degraded lands does not displace existing land uses. Restoration enhances, rather than changes, biodiversity and existing agriculture. We suggest this presents the maximum “responsible” land restoration potential that’s available for climate mitigation.

We found this would result in a median 378 billion tonnes of CO2 removed from the atmosphere between 2020 and 2100. That might sound like a lot but, for perspective, global CO2 equivalent emissions were 59 billion tonnes in 2019 alone. This means the removals we could expect from nature restoration over the rest of the century is the same as just six years worth of current emissions. Based on this CO2 removal potential, we assessed the impacts on peak global warming and century-long temperature reduction. We found nature restoration only marginally lowers global warming ~ and any climate benefits are dwarfed by the scale of ongoing fossil fuel emissions, which could be over 2,000 billion tonnes of CO2 between now and 2100, under current policies.