https://www.pnas.org/content/early/2020/05/26/1921628117 https://www.pnas.org/content/early/2020/05/26/1921628117
Human influence has intensified extreme precipitation in North America
Megan C. Kirchmeier-Young and View ORCID ProfileXuebin Zhang
PNAS first published June 1, 2020 https://doi.org/10.1073/pnas.1921628117
Edited by Susan Solomon, Massachusetts Institute of Technology, Cambridge, MA, and approved April 20, 2020 (received for review December 9, 2019)
Significance
Extreme precipitation is relevant to many interests, and observations show an increasing trend that is expected to continue under future projections. Although previous work has identified an anthropogenic influence on extreme precipitation at hemispheric scales, this study finds robust results for a continental scale. We establish that anthropogenic climate change has contributed to the intensification of continental and regional extreme precipitation. Furthermore, we also show that the anthropogenic influence on North American regional precipitation will lead to more frequent and intense precipitation extremes in the future.
Abstract
Precipitation extremes have implications for many facets of both the human and natural systems, predominantly through flooding events. Observations have demonstrated increasing trends in extreme precipitation in North America, and models and theory consistently suggest continued increases with future warming. Here, we address the question of whether observed changes in annual maximum 1- and 5-d precipitation can be attributed to human influence on the climate. Although attribution has been demonstrated for global and hemispheric scales, there are few results for continental and subcontinental scales. We utilize three large ensembles, including simulations from both a fully coupled Earth system model and a regional climate model. We use two different attribution approaches and find many qualitatively consistent results across different methods, different models, and different regional scales. We conclude that external forcing, dominated by human influence, has contributed to the increase in frequency and intensity of regional precipitation extremes in North America. If human emissions continue to increase, North America will see further increases in these extremes.
Human influence has intensified extreme precipitation in North America
Megan C. Kirchmeier-Young and View ORCID ProfileXuebin Zhang
PNAS first published June 1, 2020 https://doi.org/10.1073/pnas.1921628117
Edited by Susan Solomon, Massachusetts Institute of Technology, Cambridge, MA, and approved April 20, 2020 (received for review December 9, 2019)
Significance
Extreme precipitation is relevant to many interests, and observations show an increasing trend that is expected to continue under future projections. Although previous work has identified an anthropogenic influence on extreme precipitation at hemispheric scales, this study finds robust results for a continental scale. We establish that anthropogenic climate change has contributed to the intensification of continental and regional extreme precipitation. Furthermore, we also show that the anthropogenic influence on North American regional precipitation will lead to more frequent and intense precipitation extremes in the future.
Abstract
Precipitation extremes have implications for many facets of both the human and natural systems, predominantly through flooding events. Observations have demonstrated increasing trends in extreme precipitation in North America, and models and theory consistently suggest continued increases with future warming. Here, we address the question of whether observed changes in annual maximum 1- and 5-d precipitation can be attributed to human influence on the climate. Although attribution has been demonstrated for global and hemispheric scales, there are few results for continental and subcontinental scales. We utilize three large ensembles, including simulations from both a fully coupled Earth system model and a regional climate model. We use two different attribution approaches and find many qualitatively consistent results across different methods, different models, and different regional scales. We conclude that external forcing, dominated by human influence, has contributed to the increase in frequency and intensity of regional precipitation extremes in North America. If human emissions continue to increase, North America will see further increases in these extremes.
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