Deadly future heatwaves could kill thousands in Britain, warn scientists Professor Georgina Mace, Chair of the working group for the report said: "We are not resilient to the extremes of weather that we experience now and many people are already extremely vulnerable. If we continue on our current trajectory the problem is likely to get much worse as our climate and population change. By acting now we can reduce the serious risks for our children and grandchildren. Scientists calculated the impact of climate change and population changes on the chances of people being affected by floods, droughts and heatwaves around the world. In the UK a dense and increasingly ageing population means that heatwaves were the most serious threat. The British population is expected to swell to 75 million by 2011 with a huge rise in the number of pensioners. More than 2,000 British deaths were attributed to the warmest summer for 500 years in 2003. Last year, up to 760 people died in England alone during the July heatwave. Scientists adopted a "worst case" scenario by assuming an increase in average temperatures around the world of 2.6 - 4.8C by 2100. But global warming is on course to reach this level unless governments agree to a meaningful strategy for cutting greenhouse gas emissions at critical talks next year. The researchers defined a heatwave as a run of five days during which night-time temperatures are at least 5C above the norm. The report issued an urgent call to both governments and private companies to do more to address extreme weather hazards. The experts recommended that big engineering projects should be combined with natural ecosystem-based approaches such as re-establishing flood plains, protecting coastlines with mangrove forests, and planting vegetation. The scientists also warned that unless companies improved the way they handle weather risks their credit ratings could suffer. Co-author Rowan Douglas, chairman of the Willis Research Network - which advises public and private institutions on risk, said it was important that city planners also factor in the increased likelihood of extreme weather events. "At a macro level, we will re-build most of the world's cities in the next 30 years, literally," he said. We have a choice whether to build them to be vulnerable or resilient. The report did not look at wind damage, which poses the greatest potential risk to property in the UK. Prof Joanna Haigh, Professor of Atmospheric Physics and Co-Director of the Grantham Institute for Climate Change and Environment, Imperial College London, said: Following widely-reported projections of global mean temperature rise this report spells out very clearly the potential impact of climate change on the lives of real people across the globe. While it is impossible to predict the occurrence of a particular extreme weather event in a given place it is clear that the risk of occurrence of such events is increasing, and the potential impacts disastrous. Prof Andrew Watkinson, Professor of Environmental Sciences at the University of East Anglia (UEA), added:"This timely report reminds us that extreme weather events affect us all, that we are not as resilient to current extreme events as we could be and that the nature of extreme events is likely to change in the future." Dr Grant Allen, Atmospheric physicist at the University of Manchester, said: "One thing is for sure - what once was an extreme weather event will become more normal. It is essentially a widening of the weather spectrum: more frequent floods, droughts, heatwaves and hurricanes.