The impacts of climate change are already being felt in the UK and urgent action is required to address the risks.
The warning from the Committee on Climate Change’s (CCC) Adaptation Sub-Committee (ASC) follows more than three years of work involving hundreds of leading scientists and experts.
Its 2,000-page report states 14 out of the 15 hottest years on record have already occurred globally since 2000.
It warns changes to the UK climate are likely to include periods of too much or too little water, increasing average and extreme temperatures and sea level rise.
Some of the most urgent risks for the nation resulting from the changes are flooding and coastal change risks to communities, business and infrastructure, water supply shortages including those for energy generation, ecosystem damage, heatwaves and shocks to the global food system.
If emissions spiral, temperatures in London could hit 48°C in an extreme scenario although experts say that isn’t expected to happen.
Lord Krebs, ASC Chairman said: “The impacts of climate change are becoming ever clearer, both in the United Kingdom and around the world. We must take action now to prepare for the further, inevitable changes we can expect.
“Our independent assessment today, supported by the work of hundreds of scientists and other experts, identifies the most urgent climate change risks and opportunities which need to be addressed. Delaying or failing to take appropriate steps will increase the costs and risks for all UK nations arising from the changing climate.”
The government insists it is “committed to making sure the UK is prepared for the challenges of climate change”.
A spokesperson added: “That is why we are investing record amounts in flood defences and developing a long term plan for the environment. We continue to work closely with more than 250 organisations spanning central government, businesses, councils and academia in taking action to adapt to the effects of climate change.”
The National Adaptation Programme is expected to be updated in 2018 based on this new assessment.
Last week the CCC warned shale gas production will not be consistent with the UK’s climate targets unless there are tougher regulations in place.