Carbon Sequestration

Improving the structure of our soils and returning unproductive agricultural land to permanent pasture could be a game-changer in the battle against rising levels of CO2.

According to the Royal Society, carbon capture by the world’s farmlands, if they were better managed, could total as much as ten billion tonnes of carbon dioxide a year – more than the annual carbon dioxide accumulation in the atmosphere. Carbon Farmers of America, a company selling ‘Carbon Sinks’ to clients interested in helping reverse climate change, endorse this. They estimate that if the content of organic matter in the world’s farmed soils was increased by as little as 1.6%, the problem of climate change would be solved.

Alan Savory, Zimbabwean ecologist, proponent of holistic land management and, in particular, a rotational, natural grazing system with the power to return areas of desert, or ‘brittle zones’, to productive grassland (a system that has come to be known as ‘mob grazing’), goes one step further. He estimates that restoring the world’s five billion hectares of degraded grasslands to functioning ecosystems could return ten or more gigatons of excess atmospheric carbon to the terrestrial sink annually. This, he claims, would lower greenhouse gas concentrations to pre-industrial levels in a matter of decades.

Recently, after the Paris Climate Change talks in 2015, the French launched the ‘4 per 1000’ initiative. Its aim is less ambitious but the reasoning is the same: The quantity of carbon contained in the atmosphere increases by 4.3 billion tons every year. The world’s soils contain 1,500 billion tons of carbon in the form of organic material. Increasing the quantity of carbon contained in soils by just 0.4% a year – through restoring and improving degraded agricultural lands - would halt the annual increase of CO2 in the atmosphere. This would go a considerable way to achieving the Climate Change objective of limiting the global temperature increase to +1.5/2˚C, while at the same time increasing global food security by improving soil fertility and stability.

The potential for rewilding projects like Knepp to provide carbon sequestration is of increasing interest to our own government, under pressure to meet its ambitious target of reducing carbon emissions by 57% by 2030 on 1990 levels.

 

Further information:

Ball, A.S. and Pretty, J.N. ‘Agricultural influences on carbon emissions and sequestration’. In: Powell, J., et al (eds). Proceedings of the UK Organic Research 2002 Conference, Organic Centre Wales, Institute of Rural Studies, University of Wales, Aberystwyth, pp. 247-250. (2002).

Harvey, Graham. The Carbon Fields – how our countryside can save Britain. (Grass Roots, UK, 2008)

Khursheed, S., Simmons, C., Jaber, F., (2016) ‘Glomalin - a key to locking up soil carbon’. Advances in Plants & Agriculture Research, vol 4, issue 1. (2016)

Zhang, W., Hendrix, P.F., et al. ‘Earthworms facilitate carbon sequestration through unequal amplification of carbon stabilization compared with mineralization’. Nature Communications, vol. 4, article no. 2576. (2013).

‘Glomalin: hiding place for a third of the world’s stored soil carbon’. Agricultural Research Magazine, US Dept of Agriculture. (September 2002).

‘Restoring the climate through capture and storage of soil carbon using holistic planned grazing’. Savory Institute. (2013)