Global warming has made the past five years the hottest on record, with 2018 being the fourth-warmest since modern records began, according to research from the Met Office and Nasa.
The data show that global surface temperatures last year were 0.83C warmer than the average temperatures from the period 1951-1980, according to Nasa, due to the effects of greenhouse gases in the atmosphere and weather patterns.
“2018 is yet again an extremely warm year on top of a long-term global warming trend,” said Gavin Schmidt, head of Nasa’s Goddard Institute for Space Studies.
Nasa’s study, which draws on measurements from 6,300 locations, found that the warming was greatest in the Arctic, which has seen a loss of sea ice.
The impacts of global warming are “already being felt in coastal flooding, heatwaves, intense precipitation and ecosystem change,” added Mr Schmidt.
A separate report from the UK’s Met Office forecast that 2019 would be warmer than last year, and that the next five years would form part of the warmest decade on record.
“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,” said Adam Scaife, head of long-range prediction at the Met Office.
Last year was marked by intense heatwaves from Japan to the UK to the Middle East, and by a series of catastrophic wildfires in places including Greece and California.
In the US there were 14 “billion-dollar disasters” last year including Hurricane Florence and Hurricane Michael, severe tornado storms, and a drought in the US south-west, according to a new tally from the National Oceanic and Atmospheric Administration. The cost of the damage inflicted by these events — about $91bn — is the fourth-largest total since NOAA started keeping track in 1980.
The earth has already warmed about 1C since pre-industrial times, and almost all the countries in the world have pledged to limit global warming to less than 2C — a level that would require drastically cutting back on carbon dioxide emissions.
The level of carbon dioxide emissions hit record levels last year, and a panel of scientists convened by the UN warned that the world is on track for 3C of warming by the end of this century, based on current policies.
The Met Office predicts that 2019 could be 1.1C warmer than the average of the late 20th century, which would make it the second-warmest year on record, behind 2016.
Its forecast suggests that much of the warming would take place over land and in the Arctic region, as well as high northern latitudes.
There is also a change that warming could temporarily exceed 1.5C of warming during the next five years, the Met Office warned, a level that is often seen as a threshold that would trigger significant knock-on effect.
Even though 2018 was slightly cooler than 2017, scientists said the long-term warming trend was clear from the new data.
“The global temperature resembles riding up an escalator, and then jumping up and down on the escalator,” said Deke Arndt head of global environmental monitoring at NOAA, which also tracks temperatures.