Carbon is found in all of Earth’s ecosystems. It is packed into the trees and soils of forests, lies dense and deep in tropical peatlands and frozen tundra, maintains the fertility and resilience of farms, rangelands, and fisheries around the globe.
Land and oceans are natural “carbon sinks”, absorbing more than half of all greenhouse gas emissions, sparing the world from even more rapid warming. But, the loss of nature and conversion of land for agriculture and other activities caused nearly a quarter of emissions in the decade through 2016. Rising temperatures also risk turning carbon sinks into carbon sources.
Preventing the loss of carbon stocks in Earth’s ecosystems is critical to address the climate and biodiversity emergencies. As leaders debate policy options at the COP26 climate summit, a new report from the United Nations Environment Programme (UNEP) highlights the need for nature-based solutions - locally appropriate actions that address societal challenges, such as climate change, and provide human well-being and biodiversity benefits by protecting, sustainably managing and restoring ecosystems.
Nature-based solutions can reduce global warming and shift our economies and societies onto a sustainable path, the report found. With careful planning and ramped-up investment, nature-based solutions can cut net emissions by the equivalent of up to 18 gigatons of carbon dioxide per year by 2050 - a “significant proportion” of the total mitigation needed to avoid dangerous climate change.
However, these solutions must be designed well, and look for benefits beyond carbon, to succeed. The report recommends that they build on social and environmental safeguards developed for the UN Climate Convention’s REDD+ mechanism to save and restore forests, which include principles of free, prior and informed consent by local and indigenous communities.
“We have more than a decade of experience and knowledge on designing forest solutions for people, climate and nature through REDD+,” says Tim Christophersen, head of UNEP’s Nature for Climate branch and coordinator of the UN Decade on Ecosystem Restoration. “Now we can apply that knowledge to other ecosystems, to ensure that climate investments in nature have a high integrity and impact.”
Here are five key ecosystems where nature-based solutions can deliver:
Forests: where the most is at stake
Protecting, managing and restoring forests offers roughly two-thirds of the total mitigation potential of all nature-based solutions. Despite massive and ongoing losses, forests still cover more than 30 per cent of the planet’s land. Billions of people depend on them for their livelihoods, food and water. In mountainous areas, they protect settlements from floods, landslides and avalanches.
Well-funded protected areas can conserve forests with high carbon and biodiversity stocks, such as those in tropical latitudes. In working forests, sustainable harvesting and community management can prevent losses while benefitting people. Degraded and abandoned farmland can be planted with native trees or helped to regenerate naturally.
These solutions could also reduce demand for land, for instance by making existing agriculture more productive, promoting plant-rich diets and reducing food waste. The UN-REDD Programme deploys the expertise of UNEP, the Food and Agriculture Organization and UN Development Programme to support initiatives in developing countries to reduce emissions from deforestation and forest degradation, including through the use of nature-based solutions.
Peatlands: Earth’s most potent carbon stores
Peatlands may only cover 3 percent of the world’s land, but they hold nearly 30 percent of its soil carbon. Preserving and restoring peatlands means keeping them wet so that the carbon doesn’t oxidize and float off into the atmosphere. Drained peat is also susceptible to fires that can devastate wildlife, pollute whole regions and be tough to contain.
Peatland protection is a low-tech, cost-effective way to preserve massive carbon stocks and plant and animals species. Like forests, peatlands regulate freshwater supplies and prevent flooding, while supplying communities with food and fuel. The Global Peatlands Initiative aims to unlock international finance for conservation and management of peatlands so that they are not drained and displaced by farming, infrastructure and mining.
Farmlands: where carbon feeds humanity
Without carbon in the soil, humanity would starve. The more organic carbon in the soil, the more bountiful our crop yields, and the cooler the climate. Conserving and restoring the carbon content of croplands and rangelands involves nature-based solutions with new techniques like sustainable grazing, crop rotation and minimum tillage. A shift to sustainable farming with regenerated, carbon-rich soils can reduce greenhouse gas emissions from chemical fertilizers and pesticides and cut energy use during farming. Less intensive livestock-rearing can cut emissions of methane, a potent greenhouse gas, and counter the conversion of more forests and other natural areas for grazing land. The UN Decade on Restoration is working closely with partners who focus on soil conservation and restoration, such as www.4p1000.org.
Oceans and coasts: the many benefits of mangroves
Mangroves, salt marshes and seagrass beds trap and accumulate organic matter in their soils and prevent it from being lost to the atmosphere. Coastal nature-based solutions may focus on protecting communities and infrastructure from storms and rising sea levels. But any initiative to protect, sustainably use or replant mangroves or seagrass meadows also advances climate mitigation. Coastal wetlands are also habitats for spawning fish and other biodiversity that support livelihoods of coastal communities and contribute to global food security.
Cities: the urban frontier of climate change
The majority of humanity now lives and works in cities, which are introducing their own nature-based solutions. More and more municipalities are replacing ‘gray’ with ‘green’ infrastructure by creating parks, restoring urban lakes and streams, using sustainable building materials and lining streets and roofs with trees. (UNEP has developed guidelines on how countries can make their infrastructure more resilient). Such measures protect against flooding, heatwaves and disease and improve well-being of people. They encourage people to walk and cycle and consume less concrete and other carbon-intensive resources.
