The forecast for the global average surface temperature for the five-year period to 2023 is predicted to be near or above 1.0 °C above pre-industrial levels, says the Met Office. If the observations for the next five years track the forecast that would make the decade from 2014 to 2023 the warmest run of years since records began.

The Met Office says that 2015 was the first year in which the global annual average surface temperature reached 1C above the pre-industrial level, which is generally taken to mean the temperatures between 1850 and 1900.

Each year since then, the global average has hovered close to or above the 1C mark. Now, the Met Office says that trend is likely to continue or increase over the next five years.

“We’ve just made this year’s forecasts and they go out to 2023 and what they suggest is rapid warming globally,” Prof Adam Scaife, head of long term forecasting at the Met Office, told BBC News.

“By looking at individual years in that forecast we can now see for the first time, there is a risk of a temporary, and I repeat temporary, exceedance of the all-important 1.5C threshold level set out in the Paris climate agreement.”

Professor Adam Scaife, Head of Long-Range Prediction at the Met Office said: “2015 was the first year that global annual average surface temperatures reached 1.0 °C above pre-industrial levels and the following three years have all remained close to this level. The global average temperature between now and 2023 is predicted to remain high, potentially making the decade from 2014 the warmest in more than 150 years of records.”

Alongside this forecast, 2018 is today cited to be nominally the fourth warmest year on record globally in data released by the Met Office, at 0.91±0.1°C above the long-term pre-industrial average. It follows 2015, 2016 and 2017, which are the three warmest years in the 169-year record of the HadCRUT4 dataset.

Prof Sir Brian Hoskins, chair of the Grantham Institute, Imperial College London, said: ‘Our lack of decisive action over climate change makes us like a climber ascending a mountain, knowing that there will not be enough oxygen at some height, yet still we go on.

‘Not every individual step takes us nearer disaster, but as confirmed by the Met Office, our general direction is clear.’