Nature-based solutions can help fight climate change, biodiversity loss

Nature-based solutions are actions that work with and enhance nature to help address societal challenges while also supporting global biodiversity. Tree-planting is a well-known example. Other interventions include protecting old-growth forests to reduce floods and landslides, and restoring coastal ecosystems as a defence against storms and sea level rise.

Researchers have today published the first systematic review of the evidence for using nature-based interventions from around the world.

The review investigates nearly 400 scientific studies including 290+ real-world intervention cases. Of these, most nature-based interventions (59%) were found to reduce climate impacts such as flooding, soil erosion and loss of food production, although in 12% of interventions some negative climate impacts were exacerbated.

Social, environmental, and greenhouse gas reduction benefits were also reported from nature-based solutions, suggesting they have a key role to play in global efforts to combat climate change and biodiversity loss, while also achieving other sustainable development goals. Although comparative studies were rare, where data were available nature-based solutions were found to be as or more effective than alternative approaches.

"This review shows that there is a wealth of evidence that nature-based solutions can and should play a key role in countries' plans to mitigate and adapt to climate change," says Professor Nathalie Seddon, study author and Director of the Nature-based Solutions Initiative at the University of Oxford. "But not all solutions are equally beneficial. Evidence from artificial systems, such as tree plantations made up of non-native species, often found trade-offs, where some benefits are offset by adverse effects such as decreased water availability."

To help ensure this research is taken up by policy makers, the team have developed the first online, interactive map of the scientific evidence for nature-based solutions. This portal is the first of its kind, and allows hundreds of studies to be explored. The tool is free to access at www.naturebasedsolutionsevidence.info.

"We hope policy makers will use this research to better understand which nature-based solutions are most effective, and how they can help with climate-related challenges while providing social and environmental benefits," explains Alexandre Chausson, study author and senior researcher in the Nature-based Solutions Initiative, University of Oxford. "It's not just about tree-planting and greenhouse gas removal. In many cases nature-based interventions can help communities adapt to the wave of climate change impacts we've seen over the past months, from record-breaking heatwaves to wildfires and hurricanes."

"Although seeing nature-based solutions solely through an economic lens can undervalue their benefits, it's also important to highlight their role in the green economic recovery from COVID-19," adds Alison Smith, study author and researcher at the Environmental Change Institute, University of Oxford. "In the UK for example, restoring peat bogs or native woodland has been highlighted as a potential source of green jobs."

"Nature-based solutions can also provide goods and services that help to buffer communities when other sources of income fail," adds Beth Turner, study author and researcher at the Nature-based Solutions Initiative. "In Zimbabwe, for example, protected forests provide honey to supplement food and income when crops are lost to droughts. And beyond monetary value, properly implemented nature-based solutions can empower communities and build equity, which can contribute to climate change resilience in the long term."

While the study highlights many successful nature-based solutions, the team cautions that there are still considerable research gaps. In particular, the evidence base is biased toward the Global North, despite communities in the Global South being generally more vulnerable to the impacts of climate change and having the highest direct dependency on natural resources.