The world's ocean heat content reached a record high last year and extreme weather events affected the lives of about 62 million people, displacing more than two million of them, the World Meteorological Organisation said.

The agency's annual State of the Global Climate report, launched at the United Nations in New York on Thursday, reported a slew of impacts attributed to climate change, including the melting of 3600 cubic kilometres of Greenland ice since 2002.

People pass through a section of the road damaged earlier this month by Cyclone Idai in Nhamatanda in Mozambique. Credit:AP

Last year was the world's fourth hottest on record based on surface temperatures, with each of the years between 2015 and 2018 among the four hottest years since standardised records began more than a century ago.

“The data released in this report give cause for great concern," Antonio Guterres, the UN Secretary General, said in a statement, noting average surface temperatures are about 1 degree above the pre-industrial level. “There is no longer any time for delay [on action to curb greenhouse gas emissions].”