Mineral Solutions to Global Problems

The world faces tremendous challenges to resolve the problems associated with climate change and food supply, especially in the poorer southern hemisphere. Minerals have a vital role to play in sustaining future populations, and this presentation gives a brief insight into two key areas: carbon mitigation and food security.

To achieve ambitious and legally binding carbon sequestration targets, we have to consider CO2 removal reactions that may take place on a global scale. Soils not only contain organic carbon; they contain pedogenic carbonate minerals, which form rapidly and stabilise photosynthesised carbon in a mineralised form. We can manage this process, especially through landscape design associated with urbanisation, by the addition of appropriate sources of calcium – basic igneous rocks, steel slags or concrete demolition ‘waste’.

To provide the food required by a population that will increase from 7 to 9 billion by 2050, we need to exploit the natural processes by which soil minerals provide essential plant nutrients as an appropriate companion to conventional fertiliser use. The key nutrient that we currently fail to replace in soils is K. Paradoxically, this is found in the commonest mineral, feldspar, yet all experimental work shows that feldspar releases K too slowly. In contrast, feldspar in soil can weather sufficiently rapidly to provide K and other nutrients. This is due to two factors: the community of microbes and protozoa that inhabit its surface, and the mineralogy of the soil.