Carbon Stores and Sinks

Carbon Stores

Carbon is stored in minerals, plants and animals. Animal biomass is not significant as a carbon store. In the plant kingdom, trees are significant in the carbon equation because of their size. Soils contain carbon in varying degrees, with mineral soils such as sand containing the least and organic soils such as peat containing the most. Soils are significant because of their capacity to release or absorb carbon. Soils under agricultural regimes such as tillage or drainage release carbon to the atmosphere by various mechanisms.

Significant emissions of carbon come from the destruction of forests by cutting or burning, or the drainage of peat-rich soils, as in peat bogs or moorlands. In forest clearance carbon is lost from the soil as well as from the loss of biomass (wood) which is not replaced by new growth. When forests are cleared for agriculture or development, most of the carbon in burning or decomposing trees escapes into the atmosphere as carbon dioxide. It is estimated that 3-9 billion tonnes of carbon dioxide are released in this way every year, or around 20% of global carbon emissions. On the other hand, these carbon stores can be preserved by preserving the habitats.

Carbon offsets can be paid for projects that prevent carbon being released from a carbon store in nature, in the same way that offsets can be paid for renewable energy projects that prevent carbon being emitted by a fossil fuel energy source that is theoretically displaced. To claim carbon offsets, the project needs to be clearly preventing an intact habitat from being destroyed or degraded.

Forest Moor ensures the protection of areas of forest and peatlands by funding the purchase of land areas by local nature conservation organisations. Ownership by NGOs guarantees the long-term commitment of the landowner to preserving the habitats. We also finance local communities in the tropics to protect their forest. Further detail on the Projects page.

Carbon Sinks

'Sequestration', 'absorption' or 'sinking' are terms used for taking carbon dioxide out of the atmosphere. A sink can be described as a physical state or geological location in which the carbon dioxide can have no 'greenhouse' effect. We believe that carbon sequestration represents a highly valuable method of carbon offsetting, as it is the only type of offsetting that removes carbon from the atmosphere, as opposed to merely preventing the release of further carbon.

Some examples of sinks:

• Growing trees absorb carbon dioxide and convert it into the carbon forming the wood. The carbon in an individual tree is usually not permanently sequestered, because the carbon is released to the atmosphere when the wood is burnt or rots. However, if the wood is used as fuel to replace a fossil fuel, then carbon offsetting occurs. Similarly, offsetting occurs if the wood is used as a construction material instead of energy demanding materials such as steel or cement.
• Reforested areas act as sinks by the growing of trees and in the increasing carbon stored in the soil. A newly forested area acts as a permanent carbon sink, as long as the forest remains. When individual trees die or are cut, they are replaced by new trees, and the carbon store is maintained. Practices such as land drainage and clear felling in commercial plantations can compromise or reverse the capacity of forest land to sequester carbon. Generally tropical forests exhibit the fastest accumulation of carbon stocks during growth of relatively new forests. Boreal and temperate forests show slower accumulation of carbon, but store more carbon in their soils. Recent research has shown that fully mature, or 'climax' forests continue to remove carbon from the atmosphere.
• Degraded soils reverted to more natural management, for example by restoring habitats, absorb carbon dioxide until the natural carbon level of that soil type is reached. This can take about fifty years in the case of peat lands.
• Carbon dioxide gas can be directly captured from the emissions of power stations and stored underground, for example in depleted oil wells.

Forest Moor manages projects that sink carbon dioxide into trees and soils. We pay landowners to permanently re-forest land, and we fund the purchase of degraded peatlands by local nature conservation organisations who commit to restore the habitat. Further detail on the Projects page.

Review of energy and land use projects

Carbon projects

In the regulated carbon markets there has been a significant emphasis on energy projects. Land use and forestry projects have been receiving a small proportion of the finance available. This is mainly due to the rules set by the regulating bodies, such as the UN, which do not favour land use and forestry projects. The Gold Standard, for example, can only apply to energy projects.

The perceived problems are of two kinds: pragmatic, because it is more difficult to measure carbon savings in land use and forestry projects; and in principle because of the uncertainty over the permanence of the carbon savings. However, it can be shown that the same critiques apply to energy projects.

Measuring carbon savings

On the question of the difficulty of measuring carbon savings, energy projects may not be accounting for various sources of carbon emissions that not only are difficult to measure, but would reduce the claimed carbon savings of the project. For example, renewable energy schemes are often established on undeveloped land: the project will then lead to carbon emissions from the soil. In the case of many wind energy projects, where infrastructure is established on peat soils in upland areas, the carbon emissions can be substantial. The embodied energy of constructing and decommissioning the infrastructure may not be accounted for.

Carbon accounting relies on counting the energy generated, but this is not the same as energy delivered. Where energy projects are sited in remote areas, substantial amounts of energy are lost in transmission, and this is very difficult to measure. Finally, in the case of wind energy, due to the intermittent nature of wind, extra generating capacity is required as 'spinning reserve' to be cranked up when the wind drops. This is less efficient than maintaining power stations on full steam. This loss of efficiency is unlikely to be accounted against the wind energy projects, as there are significant problems in measuring this with reference to any specific project.

Permanence

On the more fundamental principle of permanence of the carbon saving, it is assumed that the carbon not emitted by using renewable energy will never be emitted at a later date. Given that there is a finite amount of exploitable fossil fuels, this assumes that some exploitable fossil fuel will remain unexploited for ever. This is an unjustified assumption: permanence cannot in principle be guaranteed. The rate at which we are now consuming fossil fuels and the prospect that we are probably near to the peak of production imply that in all probability we will in fact burn all exploitable reserves of fossil fuels.

Carbon is stored in both mineral and biological reserves. Mineral reserves are preserved by the use of renewable energy with the aim of leaving the carbon (in the form of oil, coal and gas) underground. Biological reserves are preserved by protecting forests and soils with the aim of leaving the carbon (in the form of above and below ground biomass) in the living plants and soils. Even if protected today, both mineral and biological carbon reserves are vulnerable to being released tomorrow. In contrast to mineral reserves of carbon, biological reserves that are being preserved by specific projects are identified, so it will be known if that carbon has been released, and it can therefore be replaced by further action.

Sequestration of carbon from the atmosphere into growing forests or recovering soils is unique in creating new biological reserves of carbon.

Additionality

If human society does exhaust all exploitable supplies of fossil fuels at some point in the future, we will by necessity have to rely on renewable energy sources. The principle of additionality will then be contravened: the renewable energy generation will have to happen at some point in the future anyway. If this is the case, the best that can be said about such projects is that they have delayed the carbon emissions by an unspecified time period.

Land use projects

Land use and forestry projects on the other hand can create permanent carbon stores while at the same time directly protecting habitats and species and the range of ecosystem services. The carbon market creates a real opportunity, not just to reduce atmospheric carbon through the use of biological reserves, but also to bring substantial investment to protecting the natural world.