The week that will be: Communicating the impact of climate change via extreme weeks

As events like the 2003 European heatwave showed (where 14,000 people died in Paris alone), it is in the extremes of weather, not the mean climate, where much climate change risk lies. Communication with the public, or the testing of natural and human-made environments via simulation, has focused however on the mean situation. To many, a future 2 or even 4 °C rise in mean temperature will seem modest and hence fail to convey the scale of the issue, thereby creating a gap between reality and expectation. Here we use the idea of presenting an audience with a week-long time series of future local extreme weather as a way of bridging this gap. A week has both vernacular currency and covers the length of many heatwaves. We generate UK future weeks in 2030, 2050 and 2080 at a 5 km interval, thereby allowing interested parties to visualise for the first time likely future heatwaves in their locality. Future heatwaves of similar form as the 2003 Paris event are found, but with even higher temperatures, suggesting the likelihood of largescale mortality. We apply the approach to the conditions within a UK home under future heatwaves with return periods of 10–50 years. Conditions far beyond adaptive comfort limits are found. Weather files containing the extreme weeks for 11,326 locations have been prepared and are made available. These will be of use to those trying to explain the likely impacts of climate change, governments setting resilience policy and those using computer modelling.