Summers in the UK could be more than 5C hotter than they are today, winters could be a third wetter and sea levels could rise by more than one metre in the next half century, according to the latest climate projections released by Westminster.
The report, which draws on the latest scientific research from the Met Office and around the world, details future climate scenarios up to the end of the century.
It predicts increasing summer and winter temperatures, more extreme weather and rising sea levels, while warning urgent international action is needed to guard against the worst impacts.
The new projections, produced for the UK government’s Department for Environment, Food and Rural Affairs (Defra), are the most comprehensive to date.
They come nearly ten years after the first such report published in 2009.
The latest projections show the expected effects of various emissions scenarios and can be used to help guide future planning, development and protection measures.
Under the most extreme warming, with a global temperature rise of 4C, experts forecast summer days in southern parts of the UK will be up to 5.4C hotter by 2070.
Scotland will see a rise of up to 4C, although the smallest increase – of around 3C – is expected in the north-west of the country.
Winter days are also due to get warmer – by up to 3C in England and 2.5C across Scotland and Wales.
The chance of a summer as hot as 2018 will stand around 50 per cent by 2050.
Predictions also show there will be an increase in flooding and droughts.
Summer rainfall will drop by up to 50 per cent in the driest regions and increase by 40 per cent in the wettest. In winter there will be an average 20 per cent increase in the amount of rain across the country.
Sea levels are projected to continue rising throughout the 21st century and beyond under all emission scenarios.
This means many coastal areas will be at a greatly increased risk of flooding.
Shetland and the southern part of the UK will see the highest sea level rises by 2100, reaching up to 1.15m.
Edinburgh is the UK capital expected to be least affected, with a rise of up to 90cm.
Launching the report titled UK Climate Predictions 2018, UK environment secretary Michael Gove said: “This cutting-edge science opens our eyes to the extent of the challenge we face and shows us a future we want to avoid.
“The UK is already a global leader in tackling climate change, cutting emissions by more than 40 per cent since 1990, but we must go further.
“By having this detailed picture of our changing climate, we can ensure we have the right infrastructure to cope with weather extremes, homes and businesses can adapt, and we can make decisions for the future accordingly.”
Met Office chief scientist Stephen Belcher said: “The new science in UKCP18 enables us to move from looking at the trends associated with climate change to describing how seasonal weather patterns will change. For example, heatwaves like the one we experienced in the summer of 2018 could be normal for the UK by mid-century.”