Mitigating climate change: energy, carbon and nitrogen on the farm

Summary The evidence for climate change is unequivocal and attention is now focussed on adapting agriculture to the current and projected changes, and in mitigating emissions of greenhouse gases. Agriculture contributes directly only about 7% of the gases causing global warming, but it also contributes indirectly through the manufacture of fertilisers and the use of power and fuels on farm. Mitigation can be achieved by either reducing emissions (e.g. by decreasing the use of fossil fuels or the inputs manufactured from them, growing bioenergy crops, or adopting management practices that decrease net emissions of N2O and CH4) or adopting management practices that permit sequestration of carbon in soil or in long-lived plants. Overall, while each of the possible individual mitigation options can only make a small inroad into greenhouse gas emissions, collectively they start to make an important contribution both environmentally and economically.