2. Why Compost? | 15 mins
Carbon store
Compost stores carbon
There have been some who have disagreed with the carbon storage potential of compost over the years. They argue that composting releases greenhouse gases like C02. This is true to an extent, but it is important to remember that the carbon released is not new carbon, but the carbon that was held in all that fruit, vegetables, grass and plants. Not only that, it also holds on to some of that carbon during the composting process, so in effect it is actually storing carbon.
When compost is applied to soil, it improves its water content, reduces soil temperature and massively increases its level of humic acid, the component of soil that improves its overall ability to store carbon. This is why the UK signed up to the French government’s '4 per 1000' soil carbon initiative at the UN Climate Change Convention in Paris. This initiative aims to increase soil organic carbon by 0.4% each year to help meet the Paris targets for net GHG emissions by 2050. French government estimates suggest that this would offset up to 75% of global anthropogenic GHG emissions. The Project Drawdown report also highlighted the importance of increasing organic carbon in soil, but believed it would offset 50% of emissions.
We are still only beginning to learn the full potential of soil's ability to store carbon, and how compost can improve this. A recent study found that the soil's ability to store carbon was improved up to 2 metres deep when compost was applied around crops.
Even if you have doubts about the extent to which compost can tackle the climate crisis, hopefully this section has impressed upon you the important role our soil plays in our delicate ecosystem and how compost helps it do this more effectively.
