[caption id="attachment_806" align="alignleft" width="1240"] Commuters sweltering in summer heat in Manchester. Photograph: Christopher Thomond/The Guardian[/caption] Two of the nations that will need to adjust the most to global warming are the UK and Switzerland, where the frequency of days with uncomfortable temperatures will rise by 30% if the world heats by 2C. The research, which was published on Thursday in Nature Sustainability, concluded that while northern European countries will mostly see the biggest relative increases in uncomfortable hot days, central Africa will still have the most extreme temperatures overall. The people and infrastructure in these countries are not prepared for periods of hot weather, the study, based on climate modelling and data from the UK Met Office, predicts. The estimates by researchers at the University of Oxford are conservative, and do not include external factors such as extreme heatwaves, which would come on top of this average increase. Norway will also suffer one of the world’s most dramatic increases in days that require cooling interventions, the study finds, with a 28% increase in days with uncomfortably hot temperatures if the world misses the 1.5C target. Eight of the 10 countries with the greatest relative increase in uncomfortably hot days are expected to be in northern Europe. Researchers said northern European countries had not prepared for sustainable cooling alternatives as homes become uncomfortably hot in the summer months and infrastructure struggles to cope above certain temperatures. Cooling measures needed to face these temperatures include making use of natural ventilation, external solar protection such as window shutters and fans. “For example, sustainable cooling barely has a mention in the UK’s net zero strategy,” said co-author Dr Radhika Khosla, an associate professor at Oxford’s Smith School of Enterprise and the Environment and leader of the Oxford Martin programme on the future of cooling. She said air conditioning could add to the problem if the grid was not decarbonised and fossil fuels were used to cool homes: “Without adequate interventions to promote sustainable cooling we are likely to see a sharp increase in the use of energy guzzling systems like air conditioning, which could further increase emissions and lock us into a vicious cycle of burning fossil fuels to make us feel cooler while making the world outside hotter.” Currently, buildings in northern Europe are often made to trap heat in the cold seasons and can become swelteringly hot in summer. This needs to change if the world hits 2C of heating and the country faces a new, hotter climate. The co-lead author Dr Jesus Lizana said: “If we adapt the built environment in which we live, we won’t need to increase air conditioning. But right now, in countries like the UK our buildings act like greenhouses: no external protection from the sun in buildings, windows locked, no natural ventilation and no ceiling fans. Our buildings are exclusively prepared for the cold seasons.” The best way to avoid having to take these measures is to keep the world to the 1.5C of heating pledge made in Paris in 2015, but the chances of this are vanishing as countries burn through more fossil fuels. If this does not happen, northern European countries that do not have cooling measures in place can expect large-scale disruption. The co-lead author Dr Nicole Miranda added: “Northern European countries will require large-scale adaptation to heat resilience quicker than other countries. Extreme heat can lead to dehydration, heat exhaustion and even death, especially in vulnerable populations. It’s a health and economic imperative that we prepare for more hot days.”