We need to stop using concrete as a building material: there are enormous numbers of alternatives and the vast majority of them use a fraction of the carbon during their lifecycles.

For instance, lime stabilised soil has been used in large civil engineering projects for decades. Lime has been used as a render and a cement for thousands of years and if extracted from limestone sensibly minimises emissions to a fraction of those from concrete.

(This post written from the Centre for Alternative Technology, on lunch while I am on a course learning how to build houses out of load bearing straw bales)