From Weather to Climate: Using Medium-Range Forecasts to Quantify Long-Term Trends in Extreme Events

Oral Presentation 

The frequency and intensity of some extreme weather events, such as heatwaves, are increasing due to climate change, with significant implications for socio-economic sectors globally. This study focuses on the question of how we quantify the rate at which the probability of these severe events is changing, enhancing our ability to support effective adaptation strategies and deepen our understanding of climate change’s diverse impacts on different regions and populations. Our initial case study uses the ECMWF’s Reforecast dataset to analyse trends and the evolving risk of extreme high summer temperatures in the Pacific Northwest. We specifically explore the relationship between the probability of exceeding climatological temperature thresholds and local, regional, and global temperature changes. We identify a consistent relationship that is statistically significant in the case of local and regional trends, allowing large-scale temperature trend information to be used to provide an estimate of a risk-doubling time to complement other approaches. Our results indicate that regional and local rising temperatures significantly elevate the likelihood of extreme weather events, highlighting the growing risk associated with climate change. Our evaluation confirms the ECMWF Reforecast data as a reliable model to use as a potential source for such analyses, although limited by the relatively short (20-year) length of the dataset.