Global warming effect on alfalfa production in Mexico

Alfalfa is the main forage crop in Mexico in terms of sown surface area, with 583,561 ha, representing 57.1 % of total forage, while forage crops of maize, oats and sorghum account for 42.9 %. The aim of this study was to estimate the impact of global warming as a result of climate change, under the basis of future climate scenarios over alfalfa production in potential irrigation areas of Mexico. Anomalies of temperature and precipitation for the 2021-2080 period were estimated through an ensemble of 11 general circulation models. Potential surface areas for alfalfa production were determined by considering reference climate and future climate projections focused on two Representative Concentration Pathways (RCP) of greenhouse gases (GHG), Results suggest an increasing temperature and its influence upon the reduction of areas with a high productive potential, as progress is made towards the future, with a reduction of 24.7% in 2070 in the RCP 4.5 with respect to the reference climate. Similar results, but with greater decrease of surface areas with productive potential -a situation that becomes even worse with time-, were estimated under the basis of the RCP 8.5. A differential effect was estimated depending on the harvesting region. Given its high water demand, alfalfa may be replaced by other crops with lower water requirements, such as maize. These results could be used in the design of strategies to adapt the crop to the effects of climate change in alfalfa producing areas.