The impact of climate change on aquatic risk from agricultural pesticides in the US

We investigate how climate change may affect the acute and chronic toxicity risk to aquatic species from agricultural pesticides in 32 States of the US. We combine climate change projections from the Canadian and Hadley climate model, statistically estimated relationships between pesticide applications and climate and weather variables, and the environmental risk indicator REXTOX developed by the OECD. On average, we find that climate change is likely to increase the toxicity risk to aquatic species by 47% because of increased applications of agricultural pesticides. Daphnia and fish are more affected than algae. Across eight broad crop groups, pesticides used on pome and stone fruits and on fruiting vegetables contribute the most to aquatic risk. Within the 32 US States examined, more than 90% of the pesticide pollution impacts induced by climate change on the aquatic environment are caused by only 13 States near to the coast.