A practical tool and robust framework for evaluating greenhouse gas emissions from land-based activities

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Limiting the impacts of climate change will require concerted action across all sectors. Emission reduction polices have previously focussed on fossil fuels, as the major cause of global warming, but the scale of the challenge means that increasing attention is now being paid to other emitters and potential mitigations, including the role of agriculture and land-use in climate change strategies. But while burning fossil fuels mostly produces carbon dioxide (CO2), land-use activities such as agriculture are more associated with nitrous oxide and, in particular, methane emissions, which can complicate efforts to work out their contribution to global warming. The way in which we currently report emissions of different gases as 'carbon-dioxide equivalents' does not always represent their impacts on the climate. This means that land-managers or policy-makers do not always have appropriate information available in order to assess the impacts of different activities, or how best our landscapes can contribute to climate change mitigation.Our research will overcome this through a new way of reporting different greenhouse gas emissions. This new approach allows emissions to be directly linked to their temperature impacts, by focussing on the change in rate of methane emissions, rather than just the total emitted quantity (which is done to determine how CO2 emissions affect the climate).We will demonstrate how our framework can be implemented in an existing tool that farmers use to estimate greenhouse gas emissions (these tools are also known as 'carbon calculators'). The tool also allows farmers to appraise how different management strategies, for example, alternative livestock diets, can reduce their emissions. Our addition will take these outputs a step further, to show what this change will mean for the climate, and provide better evidence, and hence inform better decisions, than has previously been possible.The potential advantages of this approach can be validated by testing results against a simulation model of the Earth's climate system. Climate models such as this can be complicated, and are generally not designed for individual users, such as land managers, to test small-scale, specific scenarios. If we can confirm that our simpler method still provides an accurate representation of the climate response, then we will overcome this difficulty and ensure that the consequences of different activities are clearly communicated.Our project will then demonstrate how this framework can be scaled up to provide a better indicator of the climate change impacts of bigger interventions, for example, rolling out a new mitigation across a large number of farms, or making landscape-scale policy or management decisions. The research programme would therefore provide both a framework to assess the climate impacts of important landscape decisions based on recent developments in climate science, and a potential route to communicate and promote climatically beneficial activities.