What are Nature-based Solutions?
Nature-based Solutions (NbS= Nature-based solutions) for climate change, sometimes called “natural climate solutions,” include better conservation, recovery, or management of ecosystems to remove carbon dioxide (CO2) from the atmosphere. Examples include allowing forests to grow again, restoring coastal wetlands, and switching to restorative agricultural practices, such as ground cover crop rotation to make soils healthier. All of these ecosystems are able to mitigate climate change by capturing CO2 from the air and absorbing it into plants, soil, and sediments; it also provides a variety of other important benefits, such as cleaner air and water, economic benefits, and sustainable biodiversity.
Some NbS, such as conserving existing wetlands, serve primarily to prevent greenhouse gas emissions. Other examples, such as restorative agriculture and replanting of depleted-cut forests, actively remove CO2 from the atmosphere. This makes these activities a form of carbon removal. (Many nature-based solutions prevent emissions and eliminate carbon, so the difference is not clear.) Nature-based approaches to carbon removal are often considered different from “engineering” approaches, such as bioenergy with carbon capture and storage (BECCS), direct air capture with carbon storage (DACCS), and ocean alkalinization. The difference between nature-based solutions and engineering approaches, which some experts oppose, has important implications for the politics of carbon removal: the public is generally more supportive of approaches considered “natural”.
The Role of NbS in Climate Policy
NbS can help mitigate climate change, but cannot “solve” climate change on its own; NbS needs to be combined with rapid and possible reductions in greenhouse gas emissions with engineered forms of carbon removal. Bronson Griscom and his colleagues (https://www.pnas.org/content/114/44/11645) recently estimated that cost-effective nature-based solutions could contribute about 20% of the mitigation needed through 2050 to keep global warming below 2°C. And the remaining 80% should be obtained mainly from emission reductions in the energy, transportation, building and industrial sectors and, perhaps, from other approaches to carbon removal. It is also important to note that any hectare of forest or land can only store carbon to a certain degree. Once the land area reaches maximum carbon storage, it will no longer absorb additional carbon dioxide. This is another reason why NbS cannot replace emission reductions.
NbS includes a wide range of practices, and sometimes there are disagreements about what is considered an NbS. Broadly speaking, NbS falls into four categories: forestry practices, wetland-related practices, restorative agriculture, and ocean-based practices. Forestry practices include planting new forests, allowing forests to grow back naturally, and improving forest management.
Wetland-related practices focus on the conservation and restoration of peatlands and coastal wetlands, such as mangroves. Restorative agriculture ranges from practices that build soil carbon, such as untreated farming and cover crop rotation, to better agroforestry and livestock management. Marine-based practices include restoring seagrass beds or planting seaweed or shellfish to restore or expand marine ecosystems.
Advantages and Concerns
- Protecting biodiversity: NbS preserves or expands ecosystems, and therefore protects biodiversity from climate change and habitat loss.
- Reversibility: NbS stores carbon in biomass, not in permanent reservoirs, and therefore, Nbs carbon sequestration is reversible, meaning that the captured carbon can be released back into the atmosphere through forest fires , land use change or land management, or simply climate change.
- Additional benefits and methodologies: different methods have different additional benefits, ranging from cleaner air and water to erosion control, flood protection and others, with various problems and challenges related to the implementation methodology.
- Outreach, education, and training: many stakeholders may not know about the benefits of NbS or may require training to properly implement NbS.
- Financing and incentives: although NbS activities will be able to pay for themselves over time, the beginning of implementation will require the assistance of upfront costs (for example, new equipment and equipment), and additional incentives can speed up implementation.
- Proper sizing: some NbS, such as forestry, typically compete for land with other uses, so good governance can ensure that these solutions can be implemented at an appropriate scale.
- Monitoring, reporting, and verification: measuring and calculating captured carbon can be challenging, but good governance can simplify the process and help verify carbon storage.
- Protecting captured carbon: good long-term governance is needed to minimize the release of captured carbon into the atmosphere.
Disclaimer: This article is a free translation of the article posted at the following link –https://www.american.edu/sis/centers/carbon-removal/fact-sheet-nature-based-solutions-to-climate-change.cfm