Nature-based solutions reference list

Why does the 'Let Nature Help - COP26 Edition' report suggest that degraded habitat, if restored, could absorb a third of UK emissions?

The figure is the suggested contribution that restored habitats and ecosystems could make towards achieving the UK’s net zero target. It is a projection based initially on research published in Proceedings of the National Academy of Sciences looking at the role of natural climate solutions in providing CO₂ mitigation, as well as research into the potential carbon savings and sequestration provided by restoring UK habitats. This includes the 21 million tonnes CO₂ emissions that could be prevented by halting the erosion of UK peatlands, as well as the prevention of damage to marine sediments and other important carbon stores. While the carbon storing role of ecosystems on land and sea requires further research, the best available evidence suggests important land use changes and interventions to recover nature could greatly enhance the ability of these ecosystems to sequester carbon, hence our suggested figure of a third of CO₂ mitigation if all necessary changes and interventions were carried out.

References for pages 4-5 of the 'Let Nature Help - COP26 Edition' report

• The Government claims 26% of land is already protected for nature — unfortunately the reality is closer to 3%: The extent and effectiveness of protected areas in the UK, Starnes et al., Global Ecology & Conservation, 2021, https://www.sciencedirect.com/science/article/pii/S235198942100295X?via%3Dihub
• Carbon offsets commonly fail to deliver genuinely additional benefits for climate: Reforming the Voluntary Carbon Market, Compensate, 2021, https://www.compensate.com/reforming-the-voluntary-carbon-market

References for pages 6-7 of the 'Let Nature Help - COP26 Edition' report

• Natural climate solutions could provide over a third of the cost-effective CO₂ mitigation needed through 2030: Natural climate solutions, Griscom et al., Proceedings of the National Academy of Sciences of the USA, 2017, https://www.pnas.org/content/114/44/11645
• Oceans absorb 20-35% of human-made CO₂ emissions every year: Reconstruction of the history of anthropogenic CO₂ concentrations in the ocean, Khatiwala, S., F. Primeau and T. Hall, Nature, 2009, https://www.nature.com/articles/nature08526
• Globally, plants have removed 25% of human-made CO2 emissions: Effects of Changing the Carbon Cycle, Nasa Earth Observatory, 2011, https://www.earthobservatory.nasa.gov/features/CarbonCycle/page5.php
• The world’s soils contain more carbon than is stored in plants and the atmosphere combined: Global soil carbon, Scharleman, J. P. W., et al., Carbon Management Journal, 2014, https://www.tandfonline.com/doi/full/10.4155/cmt.13.77
• Globally, phytoplankton may be responsible for the transfer of about 10 billion tonnes of carbon from the atmosphere to the deep ocean every year: Importance of phytoplankton, Nasa Earth Observatory, 2010, https://www.earthobservatory.nasa.gov/features/Phytoplankton/page2.php
• A hectare of UK seagrass can store almost a tonne of carbon a year: Variability of UK seagrass sediment carbon: Implications for blue carbon estimates and marine conservation, Green A., Chadwick M, A. and Jones, P. J. S., PLOS One, 2018 https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0204431
• As a whole, the UK lost an estimated 49% of its seagrass coverage in the 35 years up to 2005: Marine health check 2005: A report to gauge the health of the UK’s sea-life, Hiscock, K., J. Sewell, J. Oakley, for WWF-UK, 2005, http://www.marlin.ac.uk/assets/pdf/marine_healthcheck05.pdf
• A hectare of saltmarsh captures over two tonnes of carbon a year: The value of carbon sequestration and storage in coastal habitats, Beaumont, N., L. Jones, A. Garbutt, and J. Hansom, Estuarine Coastal and Shelf Science, 2013, https://www.researchgate.net/publication/259512678_The_value_of_carbon_sequestration_and_storage_in_coastal_habitats
• Up to 100 hectares of saltmarsh are lost every year: https://www.exeter.ac.uk/news/research/title_701113_en.html
• Peatlands cover nearly 10% of the UK’s land area and store an estimated 3.2 billion tonnes of carbon, but are emitting an estimated 23 million tonnes of CO₂e a year: Implementation of an Emissions Inventory for UK Peatlands, Evans, C., et al., Centre for Ecology & Hydrology, 2014, https://uk-air.defra.gov.uk/assets/documents/reports/cat07/1904111135_UK_peatland_GHG_emissions.pdf
• UK grassland soils (to a depth of 1 meter) store 2 billion tonnes of carbon, 60% of which is below 30cm. Carbon in grassland soils is vulnerable to disturbances such as ploughing: Legacy effects of grassland management on soil carbon to depth, Ward, S. E., et al., 2016, https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13246
• Between 1990-2006, an estimated 14 million tonnes of CO₂ were released by UK grasslands that were converted to arable production: Carbon storage by habitat: Review of the evidence of the impacts of management decisions and condition of carbon stores and sources, Alonso, I, K Weston, R Gregg and M Morecroft, Natural England, 2012, http://publications.naturalengland.org.uk/publication/1412347
• About 1 billion tonnes of carbon are locked up in UK woodlands, mostly in the soils: UK Forests and Climate Change: Forest carbon stock, Forest Research, https://www.forestresearch.gov.uk/tools-and-resources/statistics/forestry-statistics/forestry-statistics-2018/uk-forests-and-climate-change/forest-carbon-stock/
• On land, 66% of carbon in nature-rich areas is outside protected areas: Nature helps our fight for a safe climate, RSPB, https://rspb.maps.arcgis.com/apps/Cascade/index.html?appid=2b383eee459f4de18026002ae648f7b7

References for pages 8-9 of the 'Let Nature Help - COP26 Edition' report

• Natural carbon stores are under threat from extreme weather events, which are inevitable in the next 30 years: UK Climate Change Risk Assessment 2017 Evidence Report – Summary for England, Adaptation Sub-Committee of the Committee on Climate Change, London, 2016. https://www.theccc.org.uk/uk-climate-change-risk-assessment-2017/national-summaries/england/
• Climate Change Committee says we need to see around a 40% drop in emissions from farming by 2050: Land use: Reducing emissions and preparing for climate change, Climate Change Committee, 2018, https://www.theccc.org.uk/publication/land-use-reducing-emissions-and-preparing-for-climate-change/
• By 2050 we need woodland cover in the UK to increase from 13% to 18% as a sensible contribution to Net Zero: Land use: Reducing emissions and preparing for climate change, Climate Change Committee, 2018, https://www.theccc.org.uk/publication/land-use-reducing-emissions-and-preparing-for-climate-change/
• Risks to natural carbon stores from changing climatic conditions are a top area for immediate action identified in the latest Independent UK Climate Change Risk Assessment: Independent Assessment of UK Climate Risk: Advice to Government For the UK’s third Climate Change Risk Assessment (CCRA3), Climate Change Committee, 2021, https://www.theccc.org.uk/publication/independent-assessment-of-uk-climate-risk/

Additional sources:

• UK woodlands absorb an estimated 21 million tonnes of CO₂ a year, projected to drop to 19 million by 2030: https://www.forestresearch.gov.uk/tools-and-resources/statistics/forestry-statistics/forestry-statistics-2018/uk-forests-and-climate-change/forest-carbon-stock/
• One US study found species-rich grasslands can store up to 500% more carbon than monocultures like fields of grain: http://publications.naturalengland.org.uk/file/1438141
• In the UK, 97% of wildflower meadows have been lost since 1930: https://nbn.org.uk/wp-content/uploads/2019/09/State-of-Nature-2019-UK-full-report.pdf
• Saltmarshes bury carbon in deep sediments, where it can remain for hundreds or thousands of years if undisturbed: Howard, J., et al., Clarifying the role of coastal and marine systems in climate mitigation. Front. Ecol. Environ 2017; 15 (1): 42 – 50, https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/fee.1451
• The amount of carbon stored in Scotland’s marine sediments equates to 52% of Scotland’s 2011 carbon emissions: Burrows, M.T. et al. 2014. Assessment of carbon budgets and potential blue carbon stores in Scotland’s coastal and marine environment. Scottish Natural Heritage Commissioned Report No. 761, https://www.nature.scot/doc/naturescot-commissioned-report-761-assessment-carbon-budgets-and-potential-blue-carbon-stores
• Scotland’s peat bogs are estimated to store 1620 Mt C or 0.094 Mt C km^-2, while the top 10 cm of Scotland’s marine sediments could hold up to 1767 MtC: Burrows, M.T. et al. Assessment of carbon budgets and potential blue carbon stores in Scotland’s coastal and marine environment, Scottish Natural Heritage Commissioned Report No. 761, 2014, and Smeaton, C., et al., Re-Evaluating Scotland’s Sedimentary Carbon Stocks, Scottish Marine and Freshwater Science Vol 11 No 2, 2020, https://data.marine.gov.scot/sites/default/files//SMFS%201102.pdf
• Further peatland research: https://www.iucn-uk-peatlandprogramme.org/about-peatlands/peatland-benefits/climate-regulation