As the climate and ecological crises accelerate, we desperately need to ramp up our efforts to stop the damage, and start the repair. But good news is coming from the global restoration movement: scientific insight, on-the-ground knowledge and political will are now aligning like never before, and the movement might well be finally gaining the momentum needed to start turning the tide.
A planetary emergency
Humanity is facing a double threat. On the one hand, burning fossil fuels is fast warming our planet and destabilizing the climate that allowed human civilization to flourish. On the other hand, ecosystems, on which we depend for food, water, local climate, health, shelter… have been badly damaged worldwide, and some are already showing signs of collapse. And of course, these two threats make each other worse. This is a planetary emergency. We need to act now on many different fronts simultaneously. Here is where and how the ecosystem restoration movement steps in.

Trees can help
Protecting and restoring ecosystems is a solution at the intersection of both the climate and the ecological crises. While the benefits might at first seem more obvious in terms of biodiversity, healthy ecosystems are also key to combat climate change. Plants grow by capturing carbon from the atmosphere – and when they die, part of this carbon gets stored in the soil. Restoring vegetation and soils worldwide can therefore help us remove some of the excess carbon we have put in the atmosphere. But how much exactly?
The global tree restoration potential
Two years ago, our team set out to estimate how much of the Earth could naturally support trees, outside of already existing forests, and urban and agricultural areas. We built machinelearning algorithms and trained them on millions of data points, collected by scientists all around the world. We looked at the potential for tree restoration in places that were formerly closedcanopy forests, but also in places like grasslands or wetlands which might, in their healthy state, have as much as a 10 percent tree cover. The results were staggering: in total, we found the potential for an additional trillion trees, that would, taken together, cover an area as large as the U.S. And that could sequester up to 30% of the excess carbon that currently exists in the atmosphere as a result of human activity (note that the oceans and the biosphere have taken up about half of human emissions). Our results attracted considerable media attention, and motivated the launch of the worldwide Trillion Tree Campaign in support of the UN Decade on Ecosystem Restoration.
How to do it right?
But ecosystem restoration is like any good idea – there are many ways to mess it up. That is why earlier this year, a group of civil society experts and business leaders aligned on four “Together with Nature” principles, to guide nature-based solutions to climate change.
1. Cut emissions
In order to stabilize the climate, society’s priority should be to quit burning fossil fuel as soon as possible. Planting trees should not be seen as a way to “offset” new emissions: ecosystem restoration is about repairing the damage already done, not neutralizing further damage.
2. Conserve and protect existing ecosystems
Intact soils, forests, grasslands, shrublands, wetlands and aquatic ecosystems are vital repositories of carbon and biodiversity. Protecting our last remaining strongholds of nature is critical. It is always harder to restore an ecosystem than to prevent it from being degraded in the first place.
3. Be socially responsible
It is critical that restoration projects uphold the rights and leadership of local communities and indigenous people. It has also been shown repeatedly that restoration can only be sustainable when it brings local communities social, economic and ecological benefits.
4. Be ecologically responsible
Nature-based solutions must be founded on rigorous ecological principles. Biodiversity is vital for healthy ecosystems that are more productive, resilient and beneficial.
Evidence-based restoration
While these principles set clear guidelines for what is desirable, the best way to apply them still needs to be figured out. We at the Crowther lab are ecologists, so our particular mission in this is to figure out what works best from the point of view of the ecosystem being restored. Which tree species should be restored, and in what combinations? There is more to biodiversity than trees – so can we for instance also inoculate degraded soil with fungi? Can this in turn help the trees go faster? These questions we try to answer by partnering with restoration projects on the ground, that can set up experimental plots to test hypotheses. For instance, an experiment has just been started this year both in the Yucatan peninsula of Mexico, and in Cynghordy in Wales, the latter in partnership with The Carbon Community.
Optimizing the learning process
So far, restoration projects have been learning through a lot of trial and error. But we’re running out of time. Can we optimize this process, to let the whole movement learn in real time from every success and every failure? Can we make sure all the relevant ecological data is accessible easily to everyone engaged in restoration projects? To enable this, the lab has just launched Restor: a digital platform to let everyone access ecological data from any site on Earth, monitor the progression of restoration projects, and share information within the human ecosystem of restoration projects, scientists, funders, and the public.
Ready to restore nature’s biodiversity
To avoid planetary disaster and to repair the damage that we have already done, we need action, we need tools, and we need each other – on a grand scale. And the restoration movement now has all that. Can we count you in?