Climate change and agriculture.

Summary The world's climate is warming and its effects are fraught with uncertainty. An increase in temperature and in the frequency of extreme events such as floods or droughts is predicted. The strong dependence of agriculture on climatic conditions makes it de facto a privileged field of application. This thesis aims to study the relationship between climate and agriculture, in order to assess the potential consequences of climate change, by mixing empirical and theoretical work. The first two chapters focus on developing countries through two studies examining agricultural production and profits as well as consumption decisions of Indian agricultural households. The various climate scenarios considered show an overall negative effect on production and profits, particularly for farm households in the south of the country. Irrigation as well as crop mixing, however, can reduce the damage, especially for smallholders. The next two chapters consider economically developed countries, starting with a study of European cereal yields. Projections under different climate scenarios indicate small growth in wheat yields by the end of the 21st century, compared to observations over the past 25 years. However, these small gains are accompanied by strong regional heterogeneity. For maize, small gains by the middle of the 21st century fade behind larger losses in the long term. The partial approach is then abandoned in favour of a general equilibrium analysis that studies the short-term effects of climate shocks on economic cycles, through their impact on agriculture. An increase in the variance of climate shocks in line with that predicted by climate scenarios leads to a substantial increase in macroeconomic variables such as output and inflation.