Climate change mitigation is urgent, and adaptation to climate change is crucial, particularly in agriculture, where food security is at stake. Agriculture, currently responsible for 20-30% of global greenhouse gas emissions (counting direct and indirect agricultural emissions), can however contribute to both climate change mitigation and adaptation. The main mitigation potential lies in the capacity of agricultural soils to sequester CO2 through building organic matter. This potential can be realized by employing sustainable agricultural practices, such as those commonly found within organic farming systems. Examples of these practices are the use of organic fertilizers and crop rotations including legume leys and cover crops. Mitigation is also achieved in organic agriculture through the avoidance of open biomass burning, and the avoidance of synthetic fertilizers, the production of which causes emissions from fossil fuel use. , Andreas Gattinger1, Nic Lampkin3, Urs Niggli1 Common organic practices also contribute to adaptation. Building soil organic matter increases water retention capacity, and creates more stabile, fertile soils, thus reducing vulnerability to drought, extreme precipitation events, floods and water logging. Adaptation is further supported by increased agro-ecosystem diversity of organic farms, based on management decisions, reduced nitrogen inputs and the absence of chemical pesticides. The high diversity together with the lower input costs of organic agriculture is key to reducing production risks associated with extreme weather events. All these advantageous practices are not exclusive to organic agriculture. However, they are core parts of the organic production system, in contrast to most non-organic agriculture, where they play a minor role only. Mitigation in agriculture is however not restricted to the agricultural sector alone. Consumer preferences for products from conventional or organic farms, seasonal and local production, pest and disease resistant varieties, etc. strongly influence agricultural production systems, and thus the overall mitigation potential of agriculture. Even more influential are meat consumption and food wastage. Any discussion on mitigation of climate change in agriculture thus needs to address the entire food chain, and to be linked to general sustainable development strategies. The main challenges to dealing appropriately with the climate change mitigation and adaptation potential of organic agriculture, and agriculture in general, stem from a) insufficient understanding of some of the basic processes, such as the interaction of N2O emissions and soil carbon sequestration, contributions of roots to soil carbon sequestration, and the life-cycle emissions of organic fertilizers, such as compost; b) lack of procedures for emissions accounting which adequately represent agricultural production systems with multiple and diverse outputs, which also encompass ecosystem services; c) the problem to identify and design adequate policy frameworks for supporting mitigation and adaptation in agriculture, i.e. such that do not put systemic approaches at a disadvantage due to difficulties in the quantification of emissions, and in their allocation to single products; d) the necessity to assure that the current focus on mitigation does not lead to neglect of other factors influencing the sustainability of agriculture, such as pesticide loads, eutrophication, acidification or soil erosion; and e) the open questions, how to address consumer behaviour and how to further changes in consumption patterns, in order to utilize their mitigation potential.<p>
