Climatic change and future agroclimatic potential in Europe

Abstract

AbstractIn this paper, initial results are reported of a study to evaluate the broad‐scale sensitivity of agriculture to climatic change in Europe. The study employs an agroclimatic index, effective temperature sum (ETS), to relate temperature patterns to the cultivable limits of grain maize (Zea mays). A computer mapping system for the European region is adopted to map ETS on the basis both of present‐day and of possible future mean temperatures. In this way, changes in climate can be depicted as geographical shifts of the limit of potential grain maize cultivation.The results indicate that a mean annual temperature increase of only 1°C (within the present‐day range of interannual variability) would open up large areas in southern England, the Low Countries, eastern Denmark, northern Germany and northern Poland to potential maize cultivation. An increase of 4°C would move the limit into central Fennoscandia and northern Russia. These represent rates of northward shift of approximately 200–350 km °C−1 in western Europe and 250–400 km °C−1 in eastern Europe. Comparison of these shifts with those estimated on the basis of general circulation model (GCM) projections of future temperatures suggests that a 1°C warming will be achieved well before the time the global climate responds fully to an equivalent doubling of atmospheric carbon dioxide, possibly as early as 2010. Shifts comparable with those for a 4°C warming are achieved under all the GCM scenarios of doubled CO2, occurring perhaps as soon as 2050 if the current growth in emission rates of greenhouse gases were to continue unabated. The rate of shift of the grain maize limit implied for this (high) emissions scenario is in the order of 150–200 km per decade over the next 70 years, slower than this during the next few decades, but faster thereafter.Such shifts would offer new opportunities for farmers in different regions of northern Europe. However, given the possible rapidity of the shifts, in order for these opportunities to be exploited successfully immediate attention should be directed towards more detailed assessments of crop potential in regions identified as currently marginal for grain maize.