Global temperatures in 2018 were the fourth warmest on record, US 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 0.83 degrees 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 US, 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.

Upward trend

On Wednesday, the World Meteorological Organisation announced it, too, measured 2018 as the fourth warmest on record. It said 2016 remains the warmest on record due to a particularly strong El Nino, 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.”

Mr 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. - Guardian News and Media