A United Nations report published on Wednesday showed that 2018 was the fourth warmest year on record. The years 2015 to 2017 were the others in the top four. In coming years, temperatures are likely to approach levels that most governments consider dangerous for the Earth, Reuters reported, citing the report.

The UN’s World Meteorological Organization said the global average surface temperatures in 2018 were 1 degree Celsius above pre-industrial times (1850-1900). This was calculated based on data from weather agencies in the United States, the United Kingdom, Japan and Europe.

Extreme weather events in 2018 included the floods in Kerala, wildfires in California and Greece, and drought in South Africa.

“The long-term temperature trend is far more important than the ranking of individual years, and that trend is an upward one,” said World Meteorological Organization Secretary-General Petteri Taalas in a statement. “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 extreme weather events were consistent with changing climate. “This is a reality we need to face up to,” Taalas said. “Greenhouse gas emission reduction and climate adaptation measures should be a top global priority.”

Taalas said the Arctic was warming at twice the global average rate and a large fraction of ice in the region had melted. “Those changes are affecting weather patterns outside the Arctic in the Northern Hemisphere,” he said. “What happens at the poles does not stay at the poles but influences weather and climate conditions in lower latitudes where hundreds of millions of people live.”

The British Met Office, which also contributed data to the UN organisation, said temperatures could rise to 1.5 degrees Celsius above pre-industrial times, Reuters reported. “Over the next five years, there is a one in 10 chance of one of those years breaking the threshold,” Professor Adam Scaife of the Met Office said.

Under the 2015 Paris agreement, 200 governments agreed to phase out the use of fossil fuels and limit the rise in temperatures to 2 degrees Celsius above pre-industrial times, while “pursuing efforts” for 1.5 degrees Celsius.

The Met Office forecasts for the temperatures for each of the next five years are 1 degree Celsius or more above pre-industrial levels, according to BBC.