Governments must act on greenhouse gas emissions to build resilience to extreme weather The report is likely to highlight a number of reasons why severe weather events and their impacts are on the increase. The climate is changing, and growing populations and economies mean there is more at risk. Given these trends, what should be done to prepare for climate change in this country? I chair the Adaptation Sub-Committee of the Committee on Climate Change, the Government's statutory advisor on this issue. Last winter was the wettest on instrumental record in England and Wales, and on the night of 5 December 2013, the east coast of England experienced its largest tidal surge in sixty years. These events tell quite a bit about how resilient we are as a nation and what more must be done. There is much to applaud; flood defences reduced the number of properties damaged last winter by 99 per cent. Nine thousand properties flooded but 1.4 million were protected. No-one died as a result of the December tidal surge. Three hundred and seven people were killed by similar tide levels in 1953. Investment in flood forecasting and warning services, and emergency planning, as well as in hard defences, has paid for itself in reduced flood damages many, many times over. The tidal surge was predicted days in advance, warnings were issued, and tens of thousands of people in places like Great Yarmouth were evacuated. And yet the UK is still exposed in key areas. The National Audit Office has echoed the Adaptation Sub Committee's most recent report in concluding that not enough money is being spent on flood prevention. As a result unnecessary flood damage will occur. The Environment Agency has limited funds to maintain flood structures, and budgets have suffered real-terms cuts since 2010. This means defences are likely to degrade more quickly than necessary and could fail in flood conditions. £270 million had to be found at short notice last winter to repair and replace the defences damaged by the storms. The condition of flood defences was in decline before the storms struck. New development will increase the damage caused by flood events. Homes continue to be built on the floodplain, at an average rate of 20,000 properties per year. The current approach in England is to 'build and protect'; to allow development on the floodplain as long as there are flood defences in place. In December 2012 the Government announced a special £120 million flood defence fund to unlock new development in flood risk areas. Whilst plans involving ten or more homes rarely go ahead against the advice of the Environment Agency thousands of smaller developments each year are not looked at in such detail. New laws passed in 2010 to prevent drainage from new homes causing sewers to flood have not yet been introduced. The Government now proposes a much weaker system of controls. Climate change will not just bring more flooding to the UK. The chance of high summer temperatures has already increased and there has been a trend towards more hot days per year. The 2003 heatwave in Europe was the hottest in 500 years and led to tens of thousands of premature deaths, including an estimated 2,000 in the UK. By the 2040s, a typical summer is expected to be as hot, or hotter, than it was in that year. To cope with this we need homes and buildings that can be kept cool in the summer as well as warm in winter. But current building standards are designed with the past, not the future, climate in mind. The UK has a growing, ageing population, increasingly living in flats - the most prone to overheating. As a result the number of people in the UK dying prematurely from high temperatures could triple by the 2050s, to 7,000 per year. Preparing for the impacts of climate change starts with tackling today's vulnerabilities. Doing so will deliver immediate benefit as well as build resilience to the future climate. But the most important vulnerability is the Earth's climate system. Since the industrial revolution, human activity has released 2.2 trillion tonnes of carbon dioxide into the atmosphere. The basic, undeniable, laws of physics tell us this means the earth's climate will continue to warm. The oceans act like a global thermometer, with sea levels rising as temperatures increase, and as glaciers melt. Sea levels are rising at the fastest rate in thousands of years, and this is accelerating. Satellites are now measuring more than three millimetres of sea level rise per year. It is plausible that by 2100 tides may be as much as a metre higher than they were at the beginning of the last century. Despite the so-called "pause" in global warming the earth's climate system continues to accumulate energy. 2014 could well be the hottest year in recorded history. If the current rate of global greenhouse gas emissions continues unabated the two degree celsius threshold of dangerous climate change is likely to be breached by around 2050. Three-to-five degrees of warming is currently possible by the end of the century. This would have profound implications, including for relatively wealthy countries like the UK. Last winter a strong and unusually stable jet stream pounded our coastline with a series of twelve major storms. The jet stream encircles the globe. Whilst we were experiencing storms and flooding the same jet stream pattern sent temperatures plummeting across much of North America, and brought warm, drought conditions to California. The unusual behaviour of the jet stream in recent years is being linked with the accelerated warming of the polar region and the dramatic loss of Arctic sea ice seen since the 1970s. Within decades, the Arctic could be free of ice in the summer months. I hope the Royal Society's report identifies the key challenge that must be overcome. The most important step to be taken to avoid future impacts is to prevent dangerous climate change. It will be much easier to be resilient in a two degree world than in a four degree world. The energy technologies already exist that are needed to maintain a chance of keeping global temperatures to within the two degree threshold. Their costs are small in light of the consequences we face. The recent announcements by the United States and China - the two largest emitters of greenhouse gases - are hugely significant to energise the negotiations leading to a potential global deal next year. But the reality is that their ambitions - as with the targets agreed so far by Europe - are at the low end of what may be required to stay within the two degree goal. Lord Krebs is Principal of Jesus College Oxford and Chairman of the Adaptation Sub-Committee of the Committee on Climate Change. The Committee on Climate Change is the UK Government's independent, statutory advisor on preparing for climate change