From tree planting to ‘sponge cities’: why nature-based solutions are crucial to fighting the climate crisis

The natural world underpins human civilisation on every corner of the planet. From oceans to rainforests, grasslands to mangrove swamps, ecosystems feed billions of humans, produce clean water and provide materials for shelter. As the planet heats, scientists and conservationists are urging the world to harness and restore nature to maintain a habitable planet.

What is a nature-based solution?

Nature-based solutions is an umbrella term for using the power of nature to mitigate the impact of climate change while benefiting biodiversity and human wellbeing. There are thousands of examples: planting trees to shield buildings from heat; restoring wetlands to create “sponge cities” that protect people from flooding; planting mangroves to hold back storm surges in coastal regions.

Scientists say they are a cheap and underused option for protecting humanity from the environmental crises of the 21st century, improving food and water security, human health, and shielding communities from extreme weather.

Why do we need them?

The Paris agreement is not just about limiting global heating. It also includes commitments on mitigation and adaptation to a hotter world where flooding, droughts and large storms will be more common and intense due to higher concentrations of greenhouse gases in the atmosphere from fossil fuels.

Nature can help keep us safe from the worst effects in many cases. For example, in many parts of the world, rainfall is expected to become irregular, raining too much then raining too little. Using nature to hold more water in the landscape, whether that be through expanding wetlands or even reintroducing beavers near urban areas so their dams can slow the flow of water, can improve resilience to both drought and flooding.

Why does biodiversity matter so much?

Many scientists warn that human behaviour is driving the sixth mass extinction of life on Earth, with 1 million species at risk of disappearing. This, in turn, is degrading the planet’s ability to support human life and wellbeing.

By definition, resilient and complete ecosystems are full of plants, animals and other organisms that their degraded and simplified equivalents lack.

For example, a plantation of a single tree species supports much less life, stores much less carbon and provides a fraction of the environmental benefits compared to an old growth forest that has stood for thousands of years.

If climate solutions do not harness the full richness of nature, they will often be less effective and provide far fewer benefits. As such, sometimes the simplest and most effective solution is making sure a complete ecosystem remains standing.

There are dozens of examples that demonstrate the importance of biodi