The coming five years are anticipated to be warmest period on record, Britain's Met Office said on Thursday, warning of an outside chance of Earth breaching the Paris deal 1.5C temperature rise cap before 2024. In a regular "decadal forecast" looking at predicted near-term climate trends, it said that each year between 2020-2024 is set to be 1.06-1.62C hotter than historical averages.

The Met Office forecast it "likely" that the hottest year on record, 2016, will be beaten in that time frame. "The latest five-year forecast suggests continued warming, consistent with sustained high levels of greenhouse gases," said Doug Smith, a Met Office fellow and decadal prediction export. "Uncertainties exist within the forecast, but most regions are expected to be warmer and forecast patterns suggest enhanced warming over land, especially northern parts of Europe, Asia and North America - extending the ongoing trend."

The forecast said that barring a large volcanic eruption that could dent global heating with Sun-blocking debris, average five-year temperatures are expected to be between 1.15-1.46C above pre-industrial levels.