Explained: Scotland’s carbon storage

The climate crisis is already impacting Scotland, with more rainfall and higher temperatures being recorded in recent years.

Storing CO2 to prevent it from entering the atmosphere is central to the fight against climate change. The Scottish Government is backing technological projects to capture and store carbon from industrial sites. 

However, there are also several ways that CO2 can be stored through natural processes. As part of our Solutions for Scotland project, Ferret Fact Service looked at the different ways to store carbon.

Trees

Woodlands are important for carbon storage, also known as sequestration. As trees grow, they ‘trap’ carbon to form wood, leaves and roots. This prevents it from entering the atmosphere and contributing to the climate crisis.

There is an estimated two billion tonnes of carbon stored in Scotland’s woodland and forests.

Tree cover in Scotland has increased in the last 100 years, but it still lags behind many other European countries. About 16 per cent of Scotland is covered by trees, with an average of between 700 to 800 tonnes of carbon sequestered per hectare.

The Scottish Government aims to increase this to 21 per cent by 2032. It has consistently missed its targets for new woodland planting in recent years, meeting only 90 per cent of the 16,500 hectares planned to be planted last year. 

There has been criticism of the tree planting approach in Scotland, with fast-growing and carbon-absorbing non-native species like Sitka Spruce favoured over native species and restoration of diverse woodlands. 

Analysis by The Ferret of official forestry data has shown Sitka spruce makes up 43 per cent of woodlands in Scotland. This “invasive” species can negatively impact protected bogland and heathland, and damage biodiversity, according to experts. 

Soils

According to NatureScot, there are more than three billion tonnes of carbon in Scotland’s soils in bogs, peat and swamps making up the largest source of sequestered CO2.

Twenty per cent of Scotland is covered by peatlands, which hold more than half of the land-based carbon storage. 

When in good condition, peat soil is what’s known as a ‘carbon sink’, which absorbs carbon dioxide from the atmosphere. However, damaged peatlands can become an emitter of greenhouse gases. 

According to the International Union for Conservation, damaged peatlands are responsible for almost five per cent of human-caused CO2 emissions across the world. In Scotland degraded peatlands account for 15 per cent of all carbon pollution. 

It was estimated in 2020 that about 80 per cent of Scotland’s peatlands were degraded.

The Scottish Government has set annual targets of at least 20,000 hectares of peatland restoration every year. These have been repeatedly missed. Currently, restoration rates are around just 6,000 hectares annually.

Seas

The ocean, sea lochs and coasts in and around Scotland are a key source of carbon storage, known as ‘blue carbon’. About 25 per cent of all carbon dioxide emissions in the world are absorbed by seas. 

While living species, such as those found in saltmarshes and sand dunes, as well as seagrass, kelp beds and coral reefs can store carbon, the vast majority of the ‘blue carbon’ is stored in the seafloor and sediments found in sea lochs. 

According to the Scottish Parliament Information Centre (SPICe), over 9 billion tonnes of carbon is stored in Scotland’s surrounding seas.

There are several threats to Scotland’s ‘blue carbon’ storage such as the impact of climate change, fishing practices, and pollution. Degraded carbon storage habitats could release their CO2 and become sources of carbon emissions in future. 

Carbon capture and storage

The Scottish Government’s plans for reducing carbon emissions heavily focus on the use of technology to capture CO2 from industrial processes. This is known as carbon capture and storage (CCS). 

It works by capturing carbon from processes which usually pump it into the atmosphere — like oil refineries and cement plants — then transporting it to a safe location where it can be stored, usually deep underground. 

CCS can have a significant impact on the carbon emitted from industry and aims to capture more than 90 per cent of carbon dioxide where it is used. 

Scotland’s long-term goal of reducing net emissions to zero by 2045 emissions is reliant on the use of CCS. However, it has yet to be deployed at scale in Scotland. 

The Acorn project, a CCS facility that is planned for Aberdeenshire, has received funding from the Scottish Government but has faced delays in approval from the UK Government. 

Scotland’s climate change plan update from 2020 suggested the plant had the potential to capture as much as 10 megatonnes of C02 per year by 2030, but climate campaigners have called these targets “speculative” and “unreliable”. 

Ferret Fact Service (FFS) is a non-partisan fact checker, and signatory to the International Fact-Checking Network fact-checkers’ code of principles.

All the sources used in our checks are publicly available and the FFS fact-checking methodology can be viewed here.

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Photo credit: iStock/Rini Kools