This is the first of two volumes which report detailed results from the international project on the impact of climatic variations on agriculture funded jointly by the UN Enviroment Programme and the International Institute for Applied Systems Analysis, Vienna, with additional support from the United Nations University. This volume reports results from five case studies in cool temperate and cold regions undertaken by climatologists, agronomists, agricultural economists and regional and national planners. Three sets of models were adopted in these studies to simulate in turn the climatic change, the first-order impacts on crop yields or forestry or livestock production and the second-order responses of the wider agricultural and socioeconomic sectors.