In today’s blog Graeme Buchanan, Principal Conservation Scientist, reveals a landmark new study which highlights the value of habitat restoration. Restoration of 30% of the World’s ecosystems in Priority Areas could stave off more than 70% of projected extinctions, and absorb nearly half of the carbon built up in the atmosphere since the industrial revolution.

As the world focuses on dual crises of climate change and biodiversity loss, the restoration of significant areas of land to a natural state could prevent these crises from spinning out of control. This report, published today in Nature, is the first of its kind to identify the areas and ecosystems that should be restored for the biggest climate and biodiversity benefits while minimising the financial cost.

The UN has released dire warnings that we’re 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.

Governmental discussions are underway 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. Our report will inform the discussion around restoration, biodiversity conservation, and climate change mitigation and offer insight into how reviving ecosystems can help tackle multiple goals.

Location is key

By identifying precisely which altered 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, restoration can be 13 times more cost-effective when it takes place in the highest priority locations.

Restoring 30% of the priority areas identified in the study, along with the retention of natural habitats still in their natural form, would reduce carbon emissions equivalent to 49% of all the carbon that has built up in our atmosphere over the last two centuries - more than 465 billion tonnes of carbon dioxide.

Returning specific ecosystems in all continents worldwide to their natural state would give a brighter future to the majority of land-based species of mammals, amphibians and birds under threat of extinction.

Analysing the data

Using a sophisticated multi-criteria optimization platform called PLANGEA (a mathematical approach that finds optimal solutions to multi-faceted problems), and mapping technologies, the study assessed 2,870 million hectares of ecosystems worldwide that have been converted to farmland.

Of these, 54% were originally forests, 25% grasslands, 14% shrublands, 4% arid lands and 2% wetlands. These lands were then evaluated against three factors, or objectives (animal habitats, carbon storage and cost-effectiveness) to determine what percentage of global land restored would deliver the most benefits for biodiversity and carbon at the lowest financial cost when restored.

The study was 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; 27% reduction in costs, all by focusing on areas with low implementation and opportunity costs.

By looking at the outcomes if restoration were to take place just at the national level, where each country would only restore 15% of its forests, the analysis found a reduction in biodiversity benefits by 28% and climate benefits by 29%, a rise in costs by 52%, highlighting the need for international cooperation.

Food security

Conscious of concerns that restoring ecosystems will encroach on the land needed for crop production, the study calculated how much of ecosystems could be restored without cutting into food production. We 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.

Overall, the study provides compelling evidence to policymakers seeking affordable, efficient ways to meet United Nations goals around biodiversity, climate and desertification. That restoration, when well-coordinated and carried out in combination with the conservation management of existing intact ecosystems and the better use of agricultural lands, is an unmatched, currently underused, solution.

This report was the work of 27 researchers from 12 countries from organisations including: PUC-Rio, International Institute for Sustainability, Universidade Federal do Rio de Janeiro, Botanical Garden Research Institute of Rio de Janeiro, School of Biological Sciences, University of Queensland, Institute of Environmental Science and Technology - Universitat Autònoma de Barcelona, Fluminense Federal University, School of Environmental Sciences, University of East Anglia, Department of Zoology, University of Cambridge, International Union for Conservation of Nature, UN Environment Programme World Conservation Monitoring Centre, International Institute for Applied Systems Analysis, Birdlife International and the RSPB Centre for Conservation Science.

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