Final Report Summary - CLI-EMA (Climate Change Impacts – Economic Modelling and Assessment) The aim of the CLI-EMA project is to provide theoretical and empirical advances to estimate the economic impact of climate change.The project has made substantial contributions to the literature by developing new studies of climate change impacts on agriculture in Brazil, Europe, Italy and the United States. The project has also made new contributions to study the existence of climatic “thresholds”, which, if passed, would cause great damage to agriculture. The project has also led to the first study that assess the impact of climate on the incentive to migrate of rural households in Africa.The main findings of the project can be summarized as follows (in parenthesis reference to papers):• Econometric models of climate change impacts on agriculture that control for mean temperature and precipitation in the four seasons are superior to models that use degree days during the growing season to characterize local climate conditions (Massetti, E., R. Mendelsohn and S. Chonabayashi. 2013. “Using Degree Days to Value Farmland?” Yale University and FEEM, mimeo.)• There are not temperature thresholds beyond which agricultural land values in the United States suddenly collapse. Land values decline gradually as temperature increase. (Massetti, E., and R. Mendelsohn. 2013. “Do Temperature Thresholds Threaten American Farmland?” Yale University and FEEM, mimeo.)• Agriculture in Brazil may be severely damaged by climate change. Recent development of heat-tolerant soybeans seeds varieties has increased agricultural productivity but it has also increased the vulnerability of agriculture to warming. (Massetti, E., R. do Carmo Nascimento Guiducci, A. Fortes de Oliveira and R. Mendelsohn. 2013. “The Impact of Climate Change on the Brazilian Agriculture: A Ricardian Study at Microregion Level.” Yale University, mimeo.)• Agriculture in Europe may suffer losses from climate change. Countries in Southern Europe are likely going to suffer the largest damages, while countries in Northern Europe may benefit from climate change. (Van Passel, S., E. Massetti and R. Mendelsohn. 2012. “A Ricardian Analysis of the Impact of Climate Change on European Agriculture.” FEEM Nota di Lavoro No. 083.2012 November 2012, updated on June 2014).• Migration patterns of rural households in Nigeria and Ghana are only modestly affected by average temperature and precipitations. (Cattaneo, C. and E. Massetti. 2013. “Climate and Migration in Rural Ghana and Nigeria.” FEEM, mimeo.)• There is large uncertainty in future climate change scenarios, especially at regional and sub-regional level. This uncertainty cannot be easily resolved because climate change scenarios cannot be considered strictly independent. Thus, the available sample may not be representative of the population of all possible climate change scenarios. It is possible to use methods developed to deal with structural uncertainty to provide useful guidance to policy makers. (Athanassoglou, S. and E. Massetti. 2012. “Climate Change Impacts and Ambiguity.” Yale University, mimeo.)• Furthermore, climate change scenarios generated by the same global circulation model are not robust and may not be representative of expected climate change dynamics within a contour set of the central concentration pathway. In order to provide robust scenarios climatologists need to run ensembles of exogenous forcing scenarios. (Massetti, E. 2013. “Chaos in Climate Change Impact Estimates.” Yale University and FEEM, mimeo.)• Experiments show that uncertainty increases substantially if regional climate change models are used, because each regional model can be coupled to a different global circulation model increasing enormously the number of possible scenarios. (Massetti, E., P. Marson and S. van Passel 2014. “Global or Regional Climate Scenarios for Impact Estimates? The Case of the European Agriculture.” CMCC and FEEM, mimeo.)These studies have generated methodological insights, new methods and impact estimates that are of interest to researchers and policy makers as well.For further information see [website and www.emanuele-massetti.blogspot.com]
