Attribution of UK Temperature Changes to Anthropogenic and Natural Factors

ABSTRACT Understanding the extent to which human activities have influenced regional climate is a key scientific and policy challenge. The UK is one of the world's best observed regions climatically, with a long and reliable temperature record that makes it an important test case for regional detection and attribution. Here, for the first time, we apply optimal fingerprinting to UK mean 2‐m air temperature changes using the Estimating Equations method, HadUK‐Grid observations, and CMIP6 simulations. We assess the extent to which observed UK temperature changes can be explained by natural internal variability, anthropogenic forcings, and natural external forcings. We detect a significant anthropogenic influence on warming in recent decades and identify greenhouse gases as the main driver. We also detect a cooling contribution from other anthropogenic influences in the mid‐twentieth century, likely dominated by sulphate aerosols. These results update earlier UK‐focused work and demonstrate that human influences, both warming and cooling, are detectable even at the national scale.