Restoring 30% of the World’s Ecosystems in Priority Areas Could Stave Off More than 70% of Projected Extinctions

Institute of Environmental Science and Technology of the Universitat Autònoma de Barcelona (ICTA-UAB)
  • A report in Nature involving ICTA-UAB demonstrates that restoring 30 % of World ecosystems would allow to absorb nearly half of the carbon built up in the atmosphere since the industrial revolution.
  • The report is the first of its kind to pinpoint the ecosystems that should be restored for the biggest climate and biodiversity benefits at the lowest cost possible.
  • The work constitutes a sound contribution for establishing the right policies and for offering guidelines to prioritise action to optimise impact versus action cost.


Returning specific ecosystems in all continents worldwide that have been replaced by farming to their natural state would rescue the majority of land-based species of mammals, amphibians and birds under threat of dying out. At the same time, it would be soaking up more than 465 billion tons of carbon dioxide. This follows from a report carried out by some 27 researchers from 12 countries, involving the Institute of Environmental Science and Technology of the Universitat Autònoma de Barcelona (ICTA-UAB).

Protecting 30% of the priority areas identified in the study, together with protecting ecosystems still in their natural form, would reduce the carbon emissions equivalent to 49% of all the carbon that has built up in our atmosphere over the last two centuries.

The Industrial Revolution represented a turning point leading to an increasing footprint of human activity on the environment.

“Large-scale ecosystem restoration is crucial to deal with the current climatic crisis and to mitigate losses of biodiversity and of important ecosystem functions. We show that restoration can occur much more effectively when based on clever spatial planning, maximizing benefits for biodiversity and carbon sequestration while minimizing costs”, says André Junqueira researcher at ICTA-UAB participating in the study, published in Nature.


Efforts to prevent mass extinctions more efficiently

By identifying precisely which destroyed ecosystems worldwide should be restored to deliver biodiversity and climate benefits at a low cost, without impact on agricultural production, the study is the first of its kind to provide global evidence that where restoration takes place has the most profound impact on the achievement of biodiversity, climate and food security goals.

According to the study “Global priority areas for ecosystem restoration”, restoration can be 13 times more cost-effective when it takes place in the highest priority locations. In a first part, the study focuses on the potential benefits of restoring both forest and nonforest ecosystems on a global scale. The report in Nature builds on the UN’s dire warnings in 2019 that we are on track to lose 1 million species in coming decades and that the world has mostly failed in its efforts to reach globally-set biodiversity targets in 2020, including the goal to restore 15% of ecosystems worldwide.

The next Convention on Biological Diversity will take place at Kunming (China), notorious for its UNESCO World Heritage Site.

Nations are re-doubling efforts to stave off mass extinctions in the leadup to the Convention on Biological Diversity COP15 in Kunming, China, in 2021, when a global framework to protect nature is expected to be signed. The report will also inform the discussion around restoration and offer insights into how reviving ecosystems can help tackle multiple goals.


The PLANGEA platform and derived conclusions

Using a sophisticated multi-criteria optimization platform called PLANGEA—a mathematical approach that finds “slam dunk” solutions to address multiple problems— and mapping technologies, the researchers assessed 2,870 million hectares of ecosystems worldwide that have been converted to farmland.

Of the studied farmlands, 54% were originally forests, 25% grasslands, 14% shrublands, 4% arid lands and 2% wetlands. They then evaluated these lands based on three factors, or objectives (animal habitats, carbon storage and cost-effectiveness) to determine which swathe—whether it is five, 15 or 30% —of lands worldwide would deliver the most benefits for biodiversity and carbon at the lowest cost when restored.

Map of the priority sites for the optimisation of the impact of ecosystem restoration efforts.

Researchers were further able to identify a global-level, multiple-benefits solution— unconstrained by national boundaries—that would deliver 91% of the potential benefit for biodiversity, 82% of the climate mitigation benefit, and reduce costs by 27% by focusing on areas with low implementation and opportunity costs. When researchers looked at the benefits if the restoration were to take place at the national level—which means that each country would restore 15% of its forests—they saw a reduction in biodiversity benefits by 28% and climate benefits by 29%, a rise in costs by 52%.

“These results highlight the critical importance of international cooperation in meeting these goals. It is necessary that different countries have different, complementary roles to play in meeting overarching global targets on biodiversity and climate”, explains Bernardo B. N. Strassburg, the lead author of the report.

Responding to fears that restoring ecosystems will encroach on the land needed for crop production, researchers calculated how many ecosystems could be revived without cutting into food supplies. They found that 55%, or 1,578 million hectares, of ecosystems that had been converted to farmlands, could be restored without disrupting food production. This could be achieved through the well-planned and sustainable intensification of food production, together with a reduction in food waste and a shift away from foods such as meat and cheese, which require large amounts of land and therefore produce disproportionate greenhouse gas emissions.


Insights for decision-making

"Our results provide crucial information for decision-making, indicating where forest and non-forest ecosystems can be restored in the most efficient and affordable ways and fostering the achievement of national and international restoration goals", remarks Junqueira. Overall, the study provides compelling evidence that restoration, when well-coordinated and carried out in combination with the protection of intact ecosystems and the better use of agricultural lands, is an unmatched—though currently underused—solution.

“Our results provide very strong evidence of the benefits of pursuing joint planning and implementation of climate and biodiversity solutions, which is particularly timely given the landmark meetings planned for 2021 of the associated UN conventions on climate biodiversity and land degradation,” Strassburg says.

The study provides insights that will help direct restoration efforts towards the areas where this will have the highest impact.

“While our study provides a powerful tool for large-scale spatial planning of restoration, the actual implementation of restoration on the ground needs to take into account other important considerations, such as the demands of local communities and of other stakeholders. Still, our work shows promising pathways for aligning and maximizing the ecological and socio-economic benefits of restoration”, André Junqueira adds.

The study also demonstrates a crucial but hitherto-unexplored application of the IUCN Red List of Threatened Species, and it will inform discussion next year at IUCN World Conservation Congress and fifteenth CBD Conference of the Parties regarding implementation of policy commitments, including the Bonn Challenge, the UN Decade on Ecosystem Restoration and the Sustainable Development Goals.

A new focus on prioritizing multiple outcomes of restoring ecosystems beyond forests, and beyond country level area-based targets, calls for intensifying international cooperation to realize globally important benefits of restoring the Earth’s precious ecosystems. We need to stimulate action for the sake of a healthy planet.


Image credits:

Vintage picture of factory with workers downloaded from Wikimedia Commons and licensed via a Creative Commons Attribution-Share Alike 3.0 Unported license.

Kunming UNESCO World Heritage Site picture is in the public domain and was downloaded from Pixabay.

Map with restoration priority areas kindly provided by ICTA-UAB and re-used with permission.

Picture of degraded land  forest land in Doi Suthep-Pui National Park ready for restoration downloaded from Wikimedia Commons and licensed via a Creative Commons Attribution-Share Alike 3.0 Unported license.

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