6533b873fe1ef96bd12d48ea

RESEARCH PRODUCT

Le réchauffement climatique diminue-t-il le risque de dégâts par le gel pour les cultures de climat tempéré ?

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Does global warming reduce the freezing injury risk to temperate climate crops? Winter crop response to a temperature increase is complex. Recent works point out, for cold climate vegetation, a paradoxical increase in freezing injury in a warming climate. Complementary works are needed to support these results for winter crops in temperate areas. To achieve this goal, five climatic records spanning a fifty years-long period for both daily minimum and maximum temperatures were analyzed with a model predicting frost hardiness and freezing damage for the winter pea crop. The methodological approach was based on three main steps: 1) the climate warming analysis of the 1987/1988 temperature shift, 2) the simulation from October to March of the winter freezing damage for various dates of sowing and various levels of pea frost threshold-resistance and hardening rate and 3) the modelling of evolution of freezing injury risk by simultaneously taking into account occurrence and intensity of freezing damage. The results show a 1.1°C average increase of mean annual temperature between both periods (1961/1987 and 1988/2012). A paradoxical increase of average occurrence of freezing damage events from 3.5 to 4.5 days is associated to the climate warming with highest sensitivity to the pea varietal characteritics (hardening rate and frost threshold-resistance). An opposite trend from -14 to -6 degrees is observed for the average intensity of freezing damage events. This latter trend is less sensitive to the properties of the pea varieties. Our results suggest a cautious analysis of the freezing injury risk increase paradox related to the observed climate warming. Finally, how the freezing injury risk may be affected for the various climate warming trajectories projected the 21th century.