It was only surpassed by 2016, 2017, and 2015.
Global temperatures in 2018 were the fourth warmest on record, U.S. government scientists have confirmed, adding to a stretch of five years that are now collectively the hottest period since modern measurements began.
The world in 2018 was 1.5 degrees Fahrenheit (0.83 degrees Celsius) warmer than the average set between 1951 and 1980, said NASA and the National Oceanic and Atmospheric Administration (NOAA). This means 2018’s average global temperatures were the fourth warmest since 1880, placing it behind 2016, 2017, and 2015.
This follows a broader pattern of human-induced climate change, which is boosting increasingly punishing heatwaves, sea-level rises, and extreme weather. Last year saw a pair of devastating hurricanes hit the eastern U.S., while record wildfires ravaged California.
There was disastrous flooding in India, a huge typhoon in the Philippines, and deadly wildfires in Greece and Sweden. The Arctic, which had its second-warmest year on record, experienced temperature highs that astonished scientists.
“2018 is yet again an extremely warm year on top of a long-term global warming trend,” said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies.
“The impacts of long-term global warming are already being felt—in coastal flooding, heatwaves, intense precipitation, and ecosystem change.”
NASA and NOAA’s annual climate reports, which were delayed because of the federal government shutdown, echo findings by Berkley Earth and Europe’s Copernicus Climate Change Service, which both recently stated 2018 was the fourth warmest on record.
On Wednesday, the World Meteorological Organization announced it, too, measuring 2018 as the fourth warmest on record. It said 2016 remains the warmest on record due to a particularly strong El Niño, which is a periodic event that warms parts of the Pacific Ocean and influences weather patterns around the world.
“The long-term temperature trend is far more important than the ranking of individual years, and that trend is an upward one,“ said Petteri Taalas, secretary general of the WMO. “The 20 warmest years on record have been in the past 22 years. The degree of warming during the past four years has been exceptional, both on land and in the ocean.”
Taalas said the extreme weather events of the past year have had “devastating repercussions” for people, economies, and ecosystems.
“Many of the extreme weather events are consistent with what we expect from a changing climate,” he said. “This is a reality we need to face up to. Greenhouse-gas emission reduction and climate adaptation measures should be a top global priority.”
The relentless warming has highlighted the steep challenges faced by governments if they want to avoid the worst effects of climate change. The world needs to halve its greenhouse-gas emissions by the 2030s to avoid breaching limits set out in the Paris climate agreement, the UN warned last year, at a time when global emissions show no sign of decline.
Britain’s Met Office on Wednesday warned the 1.5-degree-Celsius temperature increase limit agreed in Paris, compared with a pre-industrial baseline, could start to be exceeded far sooner than many predicted. The Met Office said there is a 10-percent chance of at least one year between 2019 and 2023 temporarily exceeding 1.5 C.
In January, the same organization warned that levels of planet-warming carbon dioxide will rise by a near-record amount in 2019. Levels of CO2 in the atmosphere have not been as prevalent on Earth for at least 3 million years—a period when the seas were 10 to 20 meters (or roughly 33 to 66 feet) higher.