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Abstract

We present an analysis to determine whether historical trends in extreme precipitation and temperature indices, as well as in yearly averages of several climate variables can be associated in part with anthropogenic climate change or explained solely by natural causes. To achieve this, we use three methodologies: a) a climate model-based approach, b) a hybrid method that combines models and observations (1979–2019), and c) a climate observations-based method (1983–2016). For each methodology, we compare the climate change signal, represented by the historical trends, to the noise generated by simulated climate datasets (using models or statistical methods) that do not include human influence. Overall, the model-based method suggests possible detection of the human influence in most temperature extreme indices and in precipitation-related indices in the northern countries. The hybrid method detects human influence in significantly fewer variables, but in many cases, consistently with those of the model-based approach. Both the hybrid and observation-based methods exhibit similar noise variability to the model-based method. Notably, due to limitations in data availability, our analysis excludes the most recent five years, during which substantial warming and an increase of extreme events have been observed globally.