Why build sustainably? Construction and use of buildings accounts for 50% of the total energy use of Europe. This is an important area to make more efficient and reduce the energy usage. So what can we change? Rob Buckley from the Dorset Centre of Rural Change suggests building with cob, chalk, earth or straw as alternatives to more energy intensive materials, using lime as an alternative to cement and sourcing local sustainably managed timber for construction works. Sustainably built houses are also more energy efficient. Straw built houses are naturally insulated and sound proofed. But even in traditional homes, huge differences can be made. Rob Buckley suggests that if British homes were insulated to the Danish standard, CO2 emissions would be reduced by half a million tonnes per year. Proper insulation and building more sustainably in the future will make a significant positive impact on the environment.