This study will aim to identify key thresholds relating to the impact of climate change on agriculture in England and Wales. A working definition of climate-related thresholds of impacts on agriculture will be developed and resolved into operable sub-parts. For each of the major agricultural sectors in England and Wales, threshold level impacts will be identified that may affect the viability of that sector or that of other sectors. Climatic conditions under which these threshold level effects may occur will be characterised; sectors and systems that will be considered will include cereals, grasses and associated livestock systems, root crops, horticulture, pests and diseases, farm-level decisions, and economic margins and land-use allocations. Points of critical sensitivity within, or between, sectors of especial vulnerability will be identified, including analysis of the water sector and its relationship with agriculture, particularly in terms of the availability of irrigation water and competition from non-agricultural use. Under various climate change scenarios, the timing, location and magnitude of exceeding the weather/climate thresholds will be determined. Particular attention will be paid to daily data from the HadCM2 experiments upon which the current UKCIP best-estimate scenarios are based. Using simple models that relate emissions to global temperature, such as MAGICC, levels of reduction that will be necessary to avoid exceeding key thresholds will be estimated. Adaptive measures that are available to buffer key impacts or exploit new opportunities for each sector will also be evaluated. Recommendations concerning policy and research will be made that enable the most effective adaptations to be considered, especially in the most vulnerable sectors and regions. Such guidelines will also formulate more useful scenarios of climate change by including information on key weather events that have special significance for agriculture in England and Wales, as well as helping identify critical rates and magnitudes of climate change and therefore determine meaningful targets for emissions reduction.