Natural forest restoration is the “best” climate solution because it offers a rare combination of environmental impact and human benefit, according to the ecologist behind a landmark scientific paper that sparked fierce debate. Professor Thomas Crowther, of ETH Zurich and founder of the Restor.eco platform, argued in the peer-reviewed journal Science in 2019 that reviving natural habitats does not simply lock away carbon – it improves livelihoods and wellbeing in ways that technological fixes cannot match. Crowther recalled that a colleague from the World Wildlife Fund warned him the claim amounted to “career suicide”, fearing it would be seen as downplaying the need to cut emissions. He agreed then and now that reducing greenhouse gases remains the most urgent priority, and that nature restoration can meet only about 30% of carbon drawdown requirements. But his point was that “best” should be measured by what works for people as well as the planet.
Other climate solutions carry painful trade-offs, Crowther noted. Stratospheric aerosol injection – pumping reflective particles into the upper atmosphere to block sunlight – could cool the land but would likely disrupt rainfall and crop growth. Direct air carbon capture has huge potential to remove CO₂, yet the financial and energy costs remain prohibitive at the scale required. By contrast, restoring natural habitats such as forests presents no trade-off when done correctly, because it harnesses the same self-reinforcing feedback loops that allowed life to flourish on Earth billions of years ago.
How feedback loops drive recovery
Feedback loops, Crowther explained, occur when the outcome of a process amplifies the process itself – like anxiety about sleeping making it harder to fall asleep. Between 3.8 billion and 4.2 billion years ago, such loops allowed life to transform a toxic planet into a habitable one. Species emerged that created opportunities for more species, generating the oxygen, food, timber and medicine that humanity depends on. But humanity’s own success has triggered damaging loops: exploitation of natural resources drives population growth, which drives more exploitation; warming soils release carbon, which accelerates warming; drying forests store less moisture, which causes more drying. These loops risk tipping the planet into a new state.
The same dynamic can be harnessed for recovery, Crowther argued. In Argentina’s Iberá National Park, the reintroduction of jaguars is a striking example of “runaway revival”. The predators reduced bloated herds of grazing herbivores, allowing wetland plants to recover. Their roots trap moisture and provide habitat for species that make the park one of the world’s most spectacular carbon sinks. Within a few years, caimans, macaws and giant otters returned. The project involved international collaboration and land donations to create Gran Iberá Park, Argentina’s largest nature park, though it has faced challenges including devastating wildfires in February 2022.
Nature-based solutions fail when they ignore complexity. Companies that create vast monocultural tree farms destroy native species; draining peatlands to cut methane releases huge amounts of CO₂. The risks and trade-offs disappear, however, when local people become the driving force behind restoration.
Human livelihoods as the engine of restoration
Time and again, Crowther wrote, restoration becomes truly sustainable when it improves the livelihoods and wellbeing of the people who live on the land. Intrinsically motivated communities become an integrated part of a natural feedback loop that gathers momentum. In Iberá, ecotourism created a “restoration economy” employing rangers, chefs, hosts, wildlife trackers and guides. In Saseri, northern India, strategic soil management and tree restoration trap water to improve yields for more than 1,200 farmers. Farmers there moved away from intensive methods that damaged soil during the Green Revolution, adopting agroforestry that combines trees with crops to combat erosion, reverse soil carbon depletion and increase resilience to climate shocks.
A thousand kilometres to the south-west, in Gujarat, Indigenous women are restoring mangroves to protect 12 coastal villages from erosion while improving fisheries, crops and livestock. These “bioshields” of salt-resistant species act as natural defences against storm surges and saline winds. The work provides wages and strengthens local governance in what Crowther described as a “community-driven response to climate change”. The Green Brigade, involving more than 18,000 women, has transformed them into ecological leaders. Mangroves are exceptionally efficient carbon sinks, storing far more carbon per acre than tropical forests, and the community-led initiatives have attracted international funding and influenced India’s MISHTI programme.
The Restor.eco platform, which Crowther co-founded and which won the Earthshot Prize, now supports over 200,000 community-led restoration projects globally, distributing more than $11 million annually to local initiatives. Crowther’s own research – which estimated 3.04 trillion trees globally, a nearly 50% decline since the agricultural revolution and a loss of about 10 billion trees each year – identified 0.9 billion hectares of land where trees could naturally grow, offering the potential to capture over 205 gigatonnes of carbon if that land were protected. But the real power, he argued, lies in directing “a tiny fraction of our collective attention and wealth – perhaps less than 1% of global GDP” towards rural land stewards.
Crowther emphasised that protecting soil communities is equally vital, because warming soils release carbon that accelerates climate change. The emotional dimension should not be dismissed: as nature bounces back, it revives hope, joy and inspiration – responses that, in themselves, can generate feedback loops for future restoration. He concluded that remarkable innovation or great sacrifice is not required. “We just need to allow a tiny fraction of our collective attention and wealth to flow towards these rural land stewards, supporting their ongoing efforts.”
