Take good care of your feet

摘要

Healthy soils can act as a carbon sink absorbing carbon and storing it. Up to 20 of the world's CO_2 emissions come from the release of carbon due to of ground disturbance; an estimated 133 billion tonnes of carbon have been released from soil since measurements began. The fact that this is mainly due to tilling and ploughing for agriculture does not let construction off the hook. Site strips and excavations in construction contribute to the release of carbon as they disturb the ground. This increases the rate of decomposition of dead plants and animals, roots and soil organisms and so speeds the release of carbon into the atmosphere. And the existing biodiversity of soil has a critical role to play, contributing to the function of all ecosystems. 'It isn't just topsoil disturbance that needs consideration, it also matters where that soil goes,' says James Gilroy, lecturer in ecology at the University of East Anglia. 'If soil is left exposed to the air or water on the surface carbon emissions will be much higher. If the soil is immediately buried again somewhere else the carbon may remain stored although that depends on whether the soil organisms survive. So an important question is what you do with the material you dig up.'