Carbon sequestration

What we need to do and where

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1. About

The world is in a climate emergency and there are global targets to reduce emissions of greenhouse gases (GHG). The Devon Carbon Plan was published in 2022 and has a target to make Devon net-zero in carbon emissions by 2050. The management, restoration and creation of wildlife habitats has a key role to play in this through what is known as carbon sequestration.

Simplistically all plants absorb carbon dioxide from the atmosphere during photosynthesis and convert this into leaves, stems and roots. Dead plant matter then becomes part of the soil. Both vegetation and soils therefore act as carbon stores.   

Vegetation and soils also naturally emit carbon dioxide through respiration (when plants release carbon dioxide) and decomposition of plant matter. However healthy wildlife habitats generally absorb more carbon than they emit and act as carbon ‘sinks’.   

Unfortunately, when habitats and their soils are disturbed, they can release large amounts of carbon dioxide and no longer act as ‘sinks’. This can occur through burning heathlands, draining wetlands and ploughing soils. When peatlands dry out, they decompose and release large amounts of both carbon dioxide and methane – another greenhouse gas that is significantly more powerful at warming the planet.  

Habitats will absorb, store and emit different amounts of carbon depending on a range of complex factors such as vegetation, soil type and health and management. Well vegetated and managed wildlife habitats with undisturbed healthy soils are generally far better at carbon sequestration than other land uses such as arable and improved grasslands (amenity and agricultural).  

Key habitats for carbon sequestration

Blanket bogs and mires on peat: Healthy peat is composed of partially decomposed vegetation which stores large amounts of carbon and so peat habitats store the most carbon per hectare. Many peatlands, however, are degrading because of historic exploitation or drainage, and in these circumstances peatlands become a net carbon emitter. Deep peat is found on Dartmoor and Exmoor and shallower peat under acidic wetland mires in areas like the Blackdown Hills. See Heath, bog, mire and species-rich rush pasture mosaics for more details.

Woodlands: Woodlands are the next best carbon store and sequester the most carbon per hectare. Simplistically, trees are great are capturing and storing carbon as they are big, complex and long lived. They reach their peak at between 25 and 40 years old.   

Wet woodlands: On peaty soils, wet woodlands can store very high amounts of carbon, so where they exist they should be highly protected. See Wet woodland for more details.

Species-rich permanent grasslands: These can store good amounts of carbon providing they are not disturbed. 

Marine habitats: Although there are significant evidence gaps in our understanding of carbon cycling for many marine and coastal habitats, it has been shown that saltmarsh, seagrass and kelp beds can store and sequester significant quantities of carbon per hectare. See Coast for more details.

You can find out more about these factors in: 

  • The LNRS Habitats and Carbon paper  
  • The LNRS Soils paper 
  • The Devon Carbon Plan monitoring report  

See Find out more. 

Health check

Draft – to be completed following Consultation to ensure it is up to date.

The Devon Carbon Plan calculated that the main GHG emissions from “Food, Land and Sea” were methane (from the digestion of food by livestock) and nitrous oxide (from manure and fertiliser) rather than CO2. These emissions accounted for 21% of Devon’s GHG emissions in 2022, with a further 5% arising from machinery.  

Little is known about the current status of carbon stocks in Devon. In 2022 Cranfield University carried out a GIS-based exercise for the National Landscapes (formerly AONBs) of England. Results estimated that the National Landscapes of Devon (East Devon, Blackdown Hills, South Devon, Tamar Valley and North Devon National Landscapes) have carbon stocks totalling 25 million tonnes (22.5 million tonnes in soil carbon and 2.7 million tonnes in biomass). Extrapolating from these estimates, Devon’s carbon stocks total ~ 125 million tonnes. 

A significant carbon store in Devon is the peat under Dartmoor’s extensive areas of blanket bog, estimated to hold 13 million tonnes of carbon. This store is, unfortunately, degrading across most of its area due to historic drainage and the exposure of bare peat to the atmosphere. Just 1% of Dartmoor’s deep peat is considered to be healthy, peat-forming bog.  

Key pressures and opportunities

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Peat soils

Devon’s blanket bogs which lie over deep peat on Dartmoor are the most important habitat in the county for carbon sequestration. However, most are degraded and exposed and are therefore releasing carbon dioxide and methane rather than storing it, and this process is being exacerbated by climate change. There are huge opportunities through the South West Peatland Partnership to restore deep peat on Dartmoor and Exmoor. Peat sequesters carbon at a slow rate and fully restoring carbon stocks can take from decades to centuries.  Funding for future restoration is urgently needed. 

See Heath, bog, mire and species-rich rush pasture mosaics for information on these habitats. 

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Trees and woodlands

There are huge opportunities to increase tree and woodland cover across Devon. The need to meet net zero targets has led to increased funding for tree planting schemes which benefits both wildlife and climate. However, it is critical that any increase in woodland cover doesn’t lead to the loss of existing wildlife habitats such as species rich grasslands. See Broadleaved woodland for details.   

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Other soils

To be added during Consultation.

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Regenerative farming

Given that agriculture is the dominant land use across Devon, the greatest opportunities to enhance carbon sequestration lie in agricultural practices. There is now a wealth of guidance on how to reduce farming emissions, increase sequestration, restore nature and soils whist maintaining yields and profitability. See Find out more.   

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Marine habitats

There is increasing interest in the potential of marine habitats to store and sequester carbon, particularly seagrass and kelp beds. However, marine habitats are less studied and there is still uncertainty around the precise mechanisms and the greenhouse gas flux from UK waters. See Coast for more details on these habitats.  

2. What we need to do and where

Priority

Better, bigger and more wildlife rich habitats and healthy soils across Devon to increase carbon sequestration, with a particular focus on peat soils and trees.   

Actions for carbon sequestration

See Find out more for links to more detailed information. Given the complexity of carbon sequestration, expert advice should be sought. 

Habitats and soils

Implement all habitat actions within the LNRS, especially: 

  • Restore saltmarsh, seagrass and kelp beds. See Coast. 

Agriculture and soils

Adopt regenerative farming techniques which reduce carbon emissions, increase soil carbon and benefit wildlife whilst maintaining farm profitability. A few headline actions include:

  • Healthy soils: Reduced tillage, avoid deep ploughing, add organic matter, reducing/avoiding chemical fertilisers and pesticides, using cover crops.
  • Grasslands: xxx

Where we need to focus action

Habitat restoration and creation

High Opportunity Areas for all habitats as set out in the LNRS.

Consult Richard Smith to identify any soilscapes which should be a focus for regenerative farming and regenerative habitat management.

3. Inspiration

Discuss and agree what to add through Consultation, especially with farming steering group.

Case studies

South West Peatland Partnership

The South West Peatland Partnership is leading efforts to restore degraded peat. 

Many farmers are adopting organic and regenerative farming techniques to improve their soil organic carbon and gain greater resilience and fertility as a result. Look out for and support farmers in your area that are following these practices. 

The Blackdown Hills National Landscape has carried out detailed studies into soil types and the carbon sequestration potential of different habitats. See Find out more for further details.

Where to visit

Soil demo sites

To be finalised during Consultation.

4. Find out more

To be finalise during Consultation.

LNRS Habitats and Carbon paper

LNRS Soils paper (or webpage) – link to be added during Consultation

Devon Carbon Plan monitoring report

Blackdown Hills National Landscape: A Guide to Soils and Carbon 

Farm Carbon Toolkit 

Regenerative Food and Farming 

The Devon Carbon Plan, produced in 2022 by the Devon Climate Emergency Response Group, is a collaborative response to the climate emergency and sets out a road map to make Devon net-zero in carbon emissions by 2050. It includes two objectives of direct relevance to the Devon LNRS:  

  • To improve the resilience of Devon’s environment against the effects of climate change  
  • To facilitate the reduction of carbon emissions to net-zero by 20250 at the latest, to include substantial nature improvement to absorb carbon.  

Linked to this objective is the action to “Maximise carbon storage in the environment”, which involves protecting, enhancing and restoring habitats and ecosystems that store carbon.

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