Scientists said that this year was on track to become the warmest on record as the global surface air temperatures breached the threshold of 1.5C for each of the past 12 months and seas had reached their warmest for 15 months in a row.

June was the 13th consecutive month to be the hottest on the books, the Copernicus Climate Change Service said. At a surface air temperature of 16.66C, this was 0.14C above the previous June high set last year.