The report offers, for the first time, a comprehensive assessment of the potential of nature-based solutions (NbS) to mitigate climate change and benefit biodiversity in the UK. Incorporating contributions from over 100 experts, the comprehensive assessment of the available evidence details the strengths, limitations and tradeoffs of NbS in different habitats across the UK.
Professor Jane Memmott, President of the British Ecological Society, said: “The Nature-based Solutions report provides a real basis for defining effective policies and incentives that will maximize the benefits of nature-based solutions in the UK for the human being. climate and biodiversity. “
The report finds that NbS can make a valuable contribution to climate change mitigation and can simultaneously protect and enhance biodiversity, improve human well-being, bring economic benefits and provide a wide range of ecosystem services.
Despite the enormous range of benefits of NbS, the report makes it clear that they should be seen as complementary to other climate and conservation actions, and not as a replacement.
One NbS priority identified in the report is the restoration of UK peatlands. The UK’s 2.6 million hectares of peatlands contain around 3 billion tonnes of carbon, but most are in a degraded state and no longer actively sequester carbon. Estimates suggest they could emit 23 million tonnes of CO2e (carbon dioxide equivalent) annually, or about half of the amount released by the country’s agricultural sector.
Restoring degraded peatlands by rewetting and revegetation can reduce and eventually stop these emissions and bring benefits in terms of biodiversity conservation and flood protection.
“Bogs are nature’s superstars.” said Dr Christian Dunn of Bangor University and lead author of the Peatlands chapter. “If we’re serious about carbon in the UK, we need to take care of our peatlands first. We need to stop draining them immediately, and then start restoring and managing them effectively.”
Restoration of UK forests can also have a significant impact as an NbS. Forests cover 13% of the UK and the report estimates there is scope to expand it significantly to sequester more carbon, although not all of the benefits will be felt until 2050. Reducing the risk of flooding , providing shade and cooling, and benefiting from the biodiversity of expanding native forests are also highlighted as positive results of woodlands as NbS.
Professor David Coomes of the University of Cambridge and lead author of the Woodlands chapter said: “For large-scale tree planting to be effective in capturing carbon, we will need to avoid species-rich grasslands, peat and forest. ‘other organic soils. However, this will reduce the UK’s ability to produce meat and dairy, meaning that a change in our diet would be needed to avoid importing more of these products and relocating our carbon footprint elsewhere. “
Grasslands are the most extensive habitat type in the UK, covering 40% of the land. However, only 2% of this land is semi-natural grassland that is both biodiverse and carbon-rich. “Over the past 70 years, grasslands have suffered a great loss of biodiversity due to the intensification of agriculture.” said Dr Lisa Norton of the UK Center for Ecology & Hydrology and lead author of the Grasslands chapter. “But this loss gives us great potential. Protecting our semi-natural grasslands and restoring low-quality grasslands will benefit biodiversity, reduce emissions through plowing, and make animal husbandry more sustainable.”
The marine environments surrounding the UK can also offer significant NbS thanks to the large habitat sizes. Salt marshes and seagrass beds are important carbon sinks and their restoration can contribute to climate mitigation. Salt marshes also provide coastal protection against sea level rise and storms and provide high biodiversity coastal habitats, especially for bird species.
Professor Rick Stafford of the University of Bournemouth and lead author of the Marine Chapter said: “In marine environments, nature-based solutions are almost always win-win. Investing in nature-based solutions that restore or protect coastal environments is an effective mechanism for biodiversity, storm protection and carbon capture with little compromise. “
Implementing NbS to help achieve zero net commitments and tackle biodiversity loss will require shared knowledge resources and effective partnerships across different policy areas. Long-term government policies, goals and commitments will be needed to support long-term investments, research and monitoring of NbS.
Although some habitats are highlighted as priorities, the report underlines that all habitats covered can provide NbS and play a role in resolving climate and biodiversity crises.
Freshwater ecosystems such as rivers and ponds hold high biodiversity, but this is threatened by climate change, as changes in rainfall patterns increase the risk of floods and droughts.
Professor Chris Spray of the University of Dundee and lead author of the freshwater chapter said: “Protecting these vulnerable ecosystems will require a ‘integral’ catchment approach that links natural environmental and socio-economic systems. For example, planting trees along riverbanks can protect biodiversity by providing shade and creating thermal refuges as well as slowing water flow to help reduce the risk of flooding. “
Barrens store high levels of carbon, primarily in the soil, so avoiding disturbing the soil will help prevent carbon emissions from this ecosystem. This disturbance could come from the encroachment of trees and shrubs that would not compensate for the loss of carbon for decades. The creation of moors from ex-arable land can also lead to increased carbon sequestration in soils and vegetation.
Agroforestry, where trees and shrubs are integrated into agricultural systems, is an NbS that ensures carbon sequestration and storage with an estimated average storage of up to 63 tonnes of carbon per hectare due to the increased presence of trees. Agroforestry also reduces the risk of flooding and soil erosion and increases biodiversity due to tree cover and the provision of habitats for insects and birds.
Urban trees mean that cities have substantial carbon sequestration potential. A case study featured in the report found that although the city of Leicester covers 0.03% of Britain’s land area, it accounts for around 0.2% of Britain’s aerial carbon stock, of which over 97 % is attributable to trees.
Urban trees also provide a localized cooling effect, estimated to save £ 22million in annual energy use in central London, for example. Additionally, trees enhance recreation and people’s connection to nature and benefit biodiversity through habitat creation and increased connectivity.
The natural establishment of native woodlands should be encouraged where appropriate. Establishing native forests in agricultural landscapes, even on a small scale, could help reconnect old forest fragments and protect wildlife.
Investing in NbS that restore or protect coastal environments offers a range of benefits with little compromise. Besides storm surge protection, coastal flood mitigation, and human well-being benefits, healthy coastal ecosystems have high biodiversity, fulfilling important ecosystem roles such as feeding grounds for fish.
Rewetting and revegetation of peatlands can slow the flow of water during certain storm events and regulate the flow of catchment water during dry periods. Peatlands can also be used as NbS to improve the quality of drinking water.
Grassland grazing by a diverse range of animals such as sheep, cattle, horses, goats and alpacas on the same area can have a positive effect on grassland diversity and greenhouse gas emissions resulting from it. Changing from continuous grazing to rotary or mixed grazing can also reduce emissions.