Soil and vegetation in The Mill Field, Charlbury’s main recreation space, absorbs and stores enough carbon to keep approximately 12 tonnes of carbon dioxide out of the atmosphere each year. This figure is sufficient to offset the carbon emissions from heating and lighting four average UK households.
These findings emerged from a carbon mapping project that assessed four prominent sites near Charlbury, part-funded by SusCha in 2021. The objective was to gather locally relevant data for the debate on how best to manage unfarmed green spaces in ways that combat climate change and support soil health.
The research was done by unpaid volunteers. The principal expense was paying for the analysis of soil samples. SusCha contributed £480. Other funding came from Charlbury Town Council.
Research method
Data on land use, vegetation, soil and management practices were analysed using the Farm Carbon Tool Kit (https://calculator.farmcarbontoolkit.org.uk/), a computer-based system developed for farmers. In addition, soil samples were taken to establish baselines for evaluating the impact of any future changes in land management practices on improving carbon storage in soil.
As plants grow and respire, they absorb carbon dioxide from the air. The carbon is combined with water and sunlight to produce energy for the plant. Some of this energy is stored for plant health and growth, while oxygen is released back into the atmosphere.
Green spaces such as parks, nature reserves and woodland can thus act as natural ‘carbon sinks’ that protect against climate change – unlike intensive agriculture which is a net contributor to global temperature rises due to emissions from fertilizers, soil tillage, farm machinery and other inputs. Agriculture accounts for about 10 percent of UK carbon emissions.
Negative emissions at Southill Solar
Southill Solar farm was one of the three other sites assessed in addition to The Mill Field. It was estimated to generate ‘net negative emissions’ equivalent to keeping more than 90 tonnes of CO2 out of the atmosphere each year. Wigwell Nature Reserve, in contrast, was estimated to be a net emitter of CO2, contributing to climate change, due to the presence of cattle on part of the site. Cattle emit methane, a powerful warming gas, through their digestive systems.
The results were preliminary and based on the imperfect data available to us at the time. Nonetheless, we think they were interesting and a useful contribution to an important debate. The longer-term ambition is to conduct a carbon survey of all unbuilt land in the parish cluster of Charlbury, Fawler and Finstock.
Click here for a copy of the full report.