Researchers report evidence suggesting human influence on extreme precipitation in North America. Extreme precipitation has increased over North America, contributing to events that caused significant economic damage in recent years. Previous research has identified an anthropogenic contribution to extreme precipitation changes at global and hemispheric scales, but attributing continental-scale trends to anthropogenic influences remains challenging. To identify anthropogenic influences in North American trends, Megan Kirchmeier-Young and Xuebin Zhang analyzed three large ensembles of climate simulations. For North America as a whole, all ensembles and the observations showed an increase in annual maximum one-day precipitation. Even when smaller geographic regions were examined, increases were observed in the majority of cases. A signal of anthropogenic forcing was detected in all ensembles at the continental scale and in certain smaller regions as well. Both the continent as a whole and most subregions exhibited increased probability of one in 20-year, one in 50-year, and one in 100-year events with 1°C of warming. The results suggest that anthropogenic climate change has contributed to intensifying extreme precipitation and increased likelihood of extreme precipitation events in North America, both of which are expected to continue with further warming, according to the authors.
Article #19-21628: "Human influence has intensified extreme precipitation in North America," by Megan C. Kirchmeier-Young and Xuebin Zhang.
MEDIA CONTACT: Megan C. Kirchmeier-Young, Environment and Climate Change Canada, Toronto, CANADA; tel: 819-938-3338, 844-836-7799; e-mail: ec.media.ec@canada.ca
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Proceedings of the National Academy of Sciences