CNN  — 

Average summer temperatures in the UK could soar by up to 5.4 degrees Celsius (9.7 degrees Fahrenheit) by 2070 unless greenhouse gas emissions are adequately cut, the country’s weather body has warned.

Sea levels in London could also rise by up to 1.15 meters by the end of the century, with increased risk of flooding throughout the country, according to the country’s most comprehensive projections of climate change, released by the Met Office Monday.

The figures represent the worst-case scenario in terms of climate change, in which global emissions of greenhouse gases continue to rise over the course of the century.

But even if the targets set out by the Paris Climate Agreement are met, keeping global temperature rises below 2 degrees above pre-industrial levels, the impacts of climate change on the country are expected to be severe.

The UK’s average annual temperature would be still projected to rise by up to 2.3 degrees Celsius by 2100 under that more positive scenario. Sea levels could also rise by up to 70 cm in London, with cities including Cardiff, Edinburgh and Belfast facing rises in the levels of their bodies of water of over half a meter.

“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’s environment secretary, Michael Gove, said.

England experienced its hottest summer on record this year, and the UK its joint-hottest – but the report warned that equally warm summers would be commonplace by 2050 under the worst-case projections, with a 50% chance of similar temperatures each year.

The UK government has said it is considering setting a net-zero target for emissions in the future. In October, the Intergovernmental Panel on Climate Change suggested that the planet will reach the crucial threshold of 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels by as early as 2030.

The report “enables us to move from looking at the trends associated with climate change, to describing how seasonal weather patterns will change,” said Met Office Chief Scientist Stephen Belcher. “For example, heatwaves like the one we experienced in the summer of 2018 could be normal for the UK by mid-century,” he added.

David Stainforth, professorial research fellow at The Grantham Research Institute on Climate Change and the Environment, described the analysis as “comprehensive and thorough,” but added that it is “based on research at the edge of scientific understanding, using methods whose reliability has been questioned.”

“I fear that the projections will perpetuate confusion between the trustable and the debatable in relation to climate change by giving the impression that climate science can provide more detail than is justified,” he said.