A Climate Change Risk Assessment (CCRA), published today, underscores the evidence for action on a hundred key climate impacts.
Flood damage, raised energy demand for cooling, water scarcity and electricity network capacity losses are among the core challenges identified.
Environment secretary Caroline Spelman said: “This world class research provides the most comprehensive case yet on why we need to take action to adapt the UK and our economy to the impacts of climate change.
“It shows what life could be like if we stopped our preparations now, and the consequences such a decision would mean for our economic stability.”
The report estimates the annual cost of flood damage in the UK could hit between £2.1 billion and £12 billion by the 2080s, compared to £1.3 billion today.
Water deficits are projected to affect between 27 million and 59 million UK citizens by the 2050s.
The analysis was designed to form a baseline and did not take into account future government or private adaptation plans.
Spelman said the content was already influencing government policy, for example the decision to focus on resilience in last month’s water white paper.
A National Adaptation Programme (NAP) is to follow in 2013, to set out how and when government will address these issues.
This will be a collaborative process, Spelman said, telling stakeholders: “We want to co-create with you the solutions to the risks that are now more accurately identified by this assessment.”
The government is required to prepare a CCRA and a NAP every five years, under the Climate Change Act 2008.