Markku Rummukainen

The ongoing climate change has been increasingly reflected in climate observations around the world, both in terms of averages and extremes, and attributed to anthropogenic climate forcing. When it comes to changing extremes, attribution to climate change is now especially well-established for heat-related extremes worldwide. Understanding changes in extremes is important for climate adaptation as well as for the general perception of ongoing climate change in society. On more regional and local scales, both detection and attribution of changes in extremes are more challenging than globally, due to the often high variability and in some cases the limited length and quality of available observational records.
In this study, we analyse the evolution of record high and low temperatures in Sweden, using high-quality temperature data from meteorological data from SMHI. We compare the number of records high and low temperature from a number of measurement sites to theoretical expectations. For example, a study of data from 36 stations during 1882-2020 shows that the daily records of high and low temperature (Tmin and Tmax) depart from a stationary climate (Fig. 1 and Table 1.) and the ratio between record high and record low temperature has a statistically significant increasing trend (Fig. 2).