The Committee on Climate Change (CCC) says climate effects are already being felt in the UK in the form of higher temperatures and changing seasons.
Using land more sensibly, adapting buildings and planning for emergencies are areas where it recommends action.
Environment Secretary Caroline Spelman describes the CCC’s adaptation report as “a wake-up call”.
“There is no part of our society which is immune from the effects of climate change,” she is due to say in a speech on Thursday.
“Britain’s economy will only be as resilient and prepared as British firms, communities and infrastructure.”
This is the first time the CCC has looked into how homes, businesses and authorities should be changing in order to deal with climate impacts.
Previously it has concerned itself with issues such as the country’s greenhouse gas emissions and energy supply.
But a degree of adaptation is vital, it concludes, because even the most drastic cuts in emissions cannot prevent some impacts.
The UK’s average temperature has already risen by 1C since the 1970s.
The CCC uses projections from computer models of climate change to forecast a higher incidence of extreme weather events such as floods, heatwaves and droughts.
“The UK must start acting now to prepare for climate change,” said Lord Krebs, chairman of the CCC’s adaptation sub-committee.
“It is not necessarily about spending more, but about spending smart and investing to save. If we get it right, we can save money in the short term and avoid large extra costs in the future.”
Although the government has taken some steps to raise awareness of the issue among businesses and ordinary people, few tangible changes have resulted.
In many places, the CCC says, the concept of adaptation is just “name-checked”.
As examples of the issues involved, the CCC points out that if new nuclear power stations are built around the coast, they must be protected against sea-level rise well beyond their operational lifetime.
Houses must be built where a water supply is assured, and supplied with drainage adequate for future storms.
Hospitals and care homes must be able to keep cool during heatwaves.
Craig Bennett, policy and campaigns director for Friends of the Earth UK, welcomed the report.
“Making our buildings and infrastructure more resilient to a changing climate can help cut emissions too,” he noted.
“For example, super-insulating our homes and buildings will keep them warmer in winter and cooler in summer, and will also cut fuel bills.”
The report is not completely full of danger signs, however, arguing that another aspect of adaptation is making sure people and businesses are prepared for new opportunities that are projected to arise.
Warmer temperatures mean the chance to grow fruits such as apricots, while wine production could spread.