England has been warned it must “adapt or die” as climate change threatens to bring rising sea levels, more pollution and more demand on water supplies.
The Environment Agency said climate change would pile extra pressure on England's water, making it harder to guarantee clean and plentiful supplies.
Agency chairwoman Emma Howard Boyd said that if the country did not become resilient to more violent weather, then deadly events such as the flooding in Germany this summer would hit the country.
“The climate crisis is global but its impacts are in your village, your shop, your home,” Ms Howard Boyd said.
“Adaptation action needs to be integral to government, businesses and communities too, and people will soon question why it isn't, especially when it is much cheaper to invest early in climate resilience than to live with the costs of inaction.”
“While mitigation might save the planet, it is adaptation, preparing for climate shocks, that will save millions of lives."
She said that despite the UK government's focus on adaptation at Cop26 in Glasgow next month, the issue was in danger of being “grievously undercooked” at the summit by the rest of the world.
“Significant climate impacts are inevitable,” Ms Howard Boyd said. "We can successfully tackle the climate emergency if we do the right things, but we are running out of time to implement effective adaptation measures.
“It is adapt or die. With the right approach we can be safer and more prosperous. So let's prepare, act and survive.”
The agency alone cannot protect everyone from increasing flood and coastal risks, and traditional defences will not be able to prevent all flooding and coastal erosion, it said in a report to the government.
There will be more and worse environmental incidents, such as flooding, water shortages and pollution, it said.
Population growth and climate change will increase water demands and mean that, if no further action is taken between 2025 and 2050, more than 3.4 billion extra litres of water a day will be needed for public supplies.
Hotter, drier summers, rising sea levels and pressure from development are adding to water supply problems for people, industry, agriculture, recreational river use and wildlife.
With 2ºC of global warming above pre-industrial levels, below the level for which the world is on track, England's winter rainfall will increase by about 6 per cent but summer rainfall will be down 15 per cent by the 2050s.
The report warns London's sea level is expected to rise by between 23 centimetres and 29cm by the 2050s, and about 45cm at 2ºC of warming, or 78cm in a much hotter world by the 2080s.