Soils are one of the world’s biggest stores of carbon. The level of carbon storage depends on several factors, including the type of organic matter, climatic conditions and land management practices, both past and present. This report explores how the level of storage over time could be measured, and how this could help improve land management practices through a payment system.

Key points

• Agricultural soils (across pasture and arable) account for more than 10% of Scotland’s estimated soil carbon. Changes in land management practices affect the balance between soil carbon accumulation and loss, with conversion from grassland to cropland as the largest single change that releases soil carbon on Scottish agricultural land. 
• Evidence suggests there is large potential for increasing carbon storage in agricultural soils through changes in management practices. Any increase in carbon in the soil is likely to have a positive impact on soil quality, whilst the climate change mitigation benefit may be modest but positive in the longer term.     
• Mechanisms for support through payments exist, but they are largely focused on wider benefits such as preventing soil erosion and there are none that currently specifically enable  soil carbon sequestration.

The boundary between productive land and hill land in Scotland has moved over time, in response to climate and also to market demand. Scotland’s climate is changing, and this will mean changes for those areas of Scotland that sit on the margins of productive agriculture.

In this context sustainable soil management is a specific challenge as Scotland adapts to a changing climate.

This report examines the four dominant ways that farmers will adapt to climate change, and their impact on different services.

Key findings:

• It is likely that land use change will result in the intensification of land management. The result would be a reduction in most aspects of natural capital including soil carbon, water quality and biodiversity. An increase in arable cropping from current levels and a switch to winter cereals could increase soil erosion and flood risk.
• An exception would be the potential increase in forestry and woodland, though the benefits ofplanting depend greatly on what is planted and where it sits within the landscape or catchment.
• It is particularly difficult to assess the likely changes in livestock numbers. This makes it difficultto assess the greenhouse gas emissions from their rearing, as it is not possible to predict thebalance of their removal to allow arable cropping, the increase in extensive livestockmanagement which would affect emissions intensity, and the intensification of management oncurrently more marginal ground.
• One approach to assessing the risk of autonomous adaptation would be to model the impacts of a set of scenarios of change so that comparison could be made with changes expected from other drivers; if potential impacts are large in comparison then greater attention would need to be given to strategies to avoid or mitigate impacts.