It predicted that the impact could be up to 45 per cent less intense than is widely accepted.
But the study emerged as other scientists said winter waves pounding the Scottish and Irish coasts have grown grow by up to 5ft 6in (1.7metres) over the past 70 years.
Rising sea levels and more intense storms are in line with global warming forecasts.
The study questioning the future intensity of climate change was carried out by American climatologist Judith Curry and UK mathematician Nick Lewis.
It is based on analysing the warming effect of greenhouse gases and other drivers of climate change, from the mid 19th century until 2016.