Protect ecosystems first for maximum carbon storage, study finds

  • When it comes to slowing down climate change, there is a natural solution that has recently taken hold of the world: large-scale tree planting and reforestation.
  • But a new study warns that other natural climate solutions should be considered first.
  • By comparing different natural climate solutions according to four criteria, the study proposes a hierarchy: protect ecosystems first, then improve their management, and finally restore them.
  • Protecting natural ecosystems has provided the greatest climate benefits, relatively quickly, at relatively low cost, while providing other benefits for people and wildlife, such as reducing the impact of extreme weather and producing clean air and water.

When it comes to slowing down climate change, there is a natural solution that has recently taken hold of the world: large-scale tree planting and reforestation. But a new study warns that other natural climate solutions should be considered first.

Indeed, by comparing different natural climate solutions (NCS) according to four criteria, the study proposes a hierarchy: protect ecosystems first, then improve their management, and finally restore them.

“I’m really glad this article got published,” said Forrest Fleischman, an associate professor at the University of Minnesota, US, who was not involved in the study. “An enormous amount of time, energy and rhetoric is being spent on restoration as a low-cost climate solution, as scientists have said protecting existing ecosystems is the priority climate solution. It’s usually much cheaper and more reliable than restoring damaged ones. What the hierarchical framework helps is to make the cost-benefit calculation of these different investments clearer.

The crises of climate change and the disappearance of nature are intimately linked. Scientists predict that climate change will alter ecosystems, causing the extinction of many species. As ecosystems like forests, grasslands, and wetlands change, they not only release carbon they once locked up, but they release additional carbon into the atmosphere that they could have stored in the past. ‘to come up. This is why, in addition to reducing emissions from the burning of fossil fuels by humanity, many scientists advocate fighting climate change and the loss of nature together, through what they call natural climate solutions, actions that improve the ability of Earth’s ecosystems to store carbon.

Deforestation in the Indonesian province of Riau. Image by Rhett A. Butler/Mongabay.

“It is very important that natural climate solutions do not replace reducing fossil fuel emissions. We absolutely need it,” said Susan Cook-Patton, lead author of the new study, who works for the global non-profit organization The Nature Conservancy (TNC). “That said, even if we were to drastically reduce our emissions, we will still need to extract additional carbon from the atmosphere and natural climate solutions are particularly useful in this context.”

There are more than 20 NCS, according to Cook-Patton, but for the purposes of the study, she and her colleagues at TNC and Conservation International, both based in Arlington, Va., and WWF, based in Washington, DC, focused on three main areas: protection, improved management and restoration of ecosystems. The scientists then compared the potential of these three solutions to four criteria that they were able to assess on a global level. It was about the amount of climate benefit each solution provides; how quickly climate impacts become apparent; the cost-effectiveness ratio, ie the climate benefit that each one brings per dollar invested; and the co-benefits for people and nature.

The analysis showed that on a large scale, the protection of natural ecosystems provides the greatest climate benefits, relatively quickly, at relatively low cost. Improved ecosystem management comes next, followed by restoration. Prioritizing the protection of intact ecosystems also brings other benefits, the authors write. These include protecting the livelihoods and cultures of indigenous peoples and local communities, reducing the impact of sea level rise and extreme weather events, and providing air and clean water.

Take Canada as an example: in a study published earlier this year, Cook-Patton and several co-authors showed that by 2030, on more than 20 NCS, preventing the conversion of grasslands and peatlands to other land uses like agriculture would provide the greatest climate benefit by keeping carbon stocks locked in the soil. Better management of agricultural land and forests would also offer great benefits.

However, the country has instead prioritized planting trees, Cook-Patton said. “Canada has this 2 billion tree program which is about planting trees and restoring tree cover. And what we discovered is that in 2030 there is very little mitigation available. The benefits of restoration efforts would only begin to appear in 2050, according to the June study, and not in the next decade, which scientists say is essential to keeping global warming below 1.5° Celsius (2.7° Fahrenheit).

“If you want significant short-term climate mitigation, you really should be thinking about protecting those intact ecosystems and improving farmland management,” Cook-Patton said.

William Bond, grassland researcher and professor emeritus at the University of Cape Town in South Africa, who was not involved in either study, said the new study’s hierarchical framework would be particularly useful to assess in countries. in developing countries, “where international funding for tree planting is a major incentive.

“It’s not a rational response to plant trees to fight climate change,” Bond said in an email. “It is an emotional concern exploited by those who profit from it, for example, by more rigorously delaying [fossil-fuel] emissions control. It is therefore up to us, the ecology and restoration ecology communities, to inform and expand public opinion about NCS options. The authors used credible data on the carbon economy and credible economic data to develop their argument. »

Cook-Patton acknowledged that local contexts could change the priority of solutions. Still, she said the purpose of the document was to get people working for businesses and governments to first think about their options for protecting and better managing ecosystems, before jumping on the restoration bandwagon.

Woodlots dominate the landscape of southern Georgia, USA. These expansive pine and cypress properties provide ideal nesting habitat for swallowtail kites, but they are always on the chopping block for harvest. Image courtesy of The Nature Conservancy.

Bond said the paper’s protect-manage-restore message can serve another audience: people wanting to contribute to climate projects who could use more information about where their money will have the greatest effect.

“On a personal level, I’m usually extremely reluctant to pay the ‘carbon tax’ when I travel. I know it’s very likely to be spent on a poorly planned reforestation project to plant trees where they probably never existed in pristine grassland,” he said. “If I knew the carbon tax would instead support the protection of these grasslands and manage them for greater carbon storage, I would fully approve of paying the carbon tax.”

Fleischman, while agreeing that the new paper’s findings are valuable, pointed to one concern. “What does ‘protect’ mean?” he wrote in an email.

Indigenous peoples, for example, play an important role in protecting natural landscapes. But major conservation organizations, including those employing the paper’s co-authors, have historically focused on creating strict protected areas, which have often had huge negative impacts on the well-being of indigenous communities. , said Fleischman.

“The document gives a brief nod to that, but I think it’s really important that this document is not read as an endorsement of the fortress conservation policies that these organizations have historically pursued,” he said. he declares. “Note that I am not at all criticizing these scientists, whom I consider excellent and many of whom have been instrumental in highlighting Indigenous contributions to conservation in their own work, but their employers.

Fleischman also said it was important to understand why restoration figures prominently in global discourses, while protection does not.

“Protection is often detrimental to powerful interests who would destroy natural ecosystems to extract resources,” he said. “These interests loom large at the global decision-making table. Restoration often fails, but that makes for a nice catchphrase, and organizations that harm the earth can engage in long-term restoration as a way to whitewash their work. Since restoration takes decades, it will be decades before we can hold them accountable for likely failures and shortcomings. Hopefully this document will make it more difficult for these organizations, but we will have to see.

This is also Cook-Patton’s hope. “My title is Senior Forest Restoration Scientist, and I love planting trees, I love restoring forests; my science aims to precisely quantify the mitigation potential of this,” she said. “But even I want to make sure people don’t forget that there are other powerful ways we can use nature to help fight climate change.”

Banner image: Plantation of trees in Fawkner, Melbourne, Australia. Image by John Englart via Wikimedia Commons (CC BY-SA 2.0).


Cook-Patton, SC, Drever, CR, Griscom, BW, Hamrick, K., Hardman, H., Kroeger, T., … Ellis, PW (2021). Protect, manage and then restore land for climate change mitigation. Nature Climate Change, 11(12), 1027-1034. doi:10.1038/s41558-021-01198-0

Drever, CR, Cook-Patton, SC, Akhter, F., Badiou, PH, Chmura, GL, Davidson, SJ, … Kurz, WA (2021). Natural climate solutions for Canada. Scientific advances, 7(23), eabd6034. doi:10.1126/sciadv.abd6034

Related listening from the Mongabay podcast: The critical role of natural forest regeneration in reforestation goals, listen here:

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Afforestation, Carbon Conservation, Carbon Emissions, Carbon Sequestration, Climate Change, Climate Change and Biodiversity, Climate Change and Conservation, Climate Change and Forests, Climate Modeling, Climate Science, Conservation, Degraded Lands, Ecological Restoration, Ecosystem Finance , Ecosystem restoration, Ecosystems, Environment, Forest carbon, Forest fragmentation, Forest recovery, Forest regeneration, Silviculture, Forests, Landscape restoration, Protected areas, Restoration, Soil carbon

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