New forecast suggests Earth is in middle of warmest-ever decade.

The world is in the middle of what is likely to be the warmest 10 years since records began in 1850, according to new data published this week by British scientists.

The forecast, published by the U.K.’s Meteorological Office (‘Met Office’), suggests that by the year 2023 global average surface temperatures will be up to 1.57°C above pre-industrial levels. This would make the decade from 2014 to 2023 the warmest run of years since records began.

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.”

Looking forward to the five-year period 2019-2023, forecast patterns suggest enhanced warming is likely over much of the globe, especially over land and at high northern latitudes, particularly the Arctic region.

Dr Doug Smith, Met Office Research Fellow said, “A run of temperatures of 1.0°C or above would increase the risk of a temporary excursion above the threshold of 1.5°C above pre-industrial levels.”

Alongside this forecast, 2018 is now cited as the fourth warmest year on record. It follows 2015, 2016 and 2017 as the four warmest years in the 169-year record of the ‘HadCRUT4’ dataset. (The HadCRUT4 dataset is a joint-initiative between government scientists and leading academics in the UK which combines land, air and sea temperature data).

Professor Tim Osborn, director of the University of East Anglia’s Climatic Research Unit, said: “The warmth of 2018 is in line with the long-term warming trend driven by the world’s emissions of greenhouse gases.”

Last October, UN scientists published a special report on the long-term impacts of a temperature rise of 1.5°C. They concluded that it without urgent attempt to cut carbon emissions the world was likely to breech the 1.5C barrier by 2030.

The Met Office report suggests this may now happen within the next five years.

"It's the first time the forecasts have shown a significant risk of exceedance,” Professor Scaife told BBC News. "But the fact that that can happen now due to a combination of general warming and the fluctuations due to things like El Niño events in the next few years does mean we are getting close to that threshold."

The World Meteorological Organization (WMO) recently published an analysis of five major international datasets that showed 20 of the warmest years on record have occurred during the last 22 years.

"Temperatures are only part of the story. Extreme and high impact weather affected many countries and millions of people, with devastating repercussions for economies and ecosystems in 2018," said WMO Secretary-General Petteri Taalas.

"Many of the extreme weather events are consistent with what we expect from a changing climate. This is a reality we need to face up to. Greenhouse gas emission reduction and climate adaptation measures should be a top global priority.”

Other researchers in the field said the new forecast for the next five years was in line with expectations, given the record level of CO2 pumped into the atmosphere in 2018.

"The forecast from the Met Office is, unfortunately, no surprise," Dr Anna Jones, an atmospheric chemist at the British Antarctic Survey told the BBC.

"Temperatures averaged across the globe are at a record all-time high, and have been for a number of years. They are driven predominantly by rising concentrations of greenhouse gases, such as carbon dioxide, that result from our continued use of fossil fuels.

"Until we reduce greenhouse gas emissions, we can expect to see upward trends in global averaged temperatures."

===/

Images courtesy The Met Office and NASA/BBC.

The NASA graphic shows global temperature anomalies between 2014 and 2018. Areas trending higher than previous averages are shown in red.

The Met Office graphic shows annual mean temperature deviations since 1850.