Attribution of extreme weather and climate events overestimated by unreliable climate simulations

Event attribution aims to estimate the role of an external driver after the occurrence of an extreme weather and climate event by comparing the probability that the event occurs in two counterfactual worlds. These probabilities are typically computed using ensembles of climate simulations whose simu...

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Detalles Bibliográficos
Autores: Bellprat, Omar|||0000-0001-6434-1793, Doblas-Reyes, Francisco|||0000-0002-6622-4280
Tipo de recurso: artículo
Fecha de publicación:2016
País:España
Institución:Universitat Politècnica de Catalunya (UPC)
Repositorio:UPCommons. Portal del coneixement obert de la UPC
Idioma:inglés
OAI Identifier:oai:upcommons.upc.edu:2117/85869
Acceso en línea:https://hdl.handle.net/2117/85869
https://dx.doi.org/10.1002/2015GL067189
Access Level:acceso abierto
Palabra clave:Extreme weather
Climate variations
Computer simulation
Climate Change
FAR
Climate models
Canvis climàtics
Medis extrems
Simulació, Mètodes de
Àrees temàtiques de la UPC::Enginyeria electrònica::Impacte ambiental
Descripción
Sumario:Event attribution aims to estimate the role of an external driver after the occurrence of an extreme weather and climate event by comparing the probability that the event occurs in two counterfactual worlds. These probabilities are typically computed using ensembles of climate simulations whose simulated probabilities are known to be imperfect. The implications of using imperfect models in this context are largely unknown, limited by the number of observed extreme events in the past to conduct a robust evaluation. Using an idealized framework, this model limitation is studied by generating large number of simulations with variable reliability in simulated probability. The framework illustrates that unreliable climate simulations are prone to overestimate the attributable risk to climate change. Climate model ensembles tend to be overconfident in their representation of the climate variability which leads to systematic increase in the attributable risk to an extreme event. Our results suggest that event attribution approaches comprising of a single climate model would benefit from ensemble calibration in order to account for model inadequacies similarly as operational forecasting systems.