GENEVA: Global temperatures in 2018 are set to be the fourth highest on record, the UN said Thursday, stressing the urgent need for action to rein in runaway warming of the planet.In a report released ahead of the COP 24 climate summit in Poland, the World Meteorological Organization pointed out that the 20 warmest years on record have been in the past 22 years, and that "2018 is on course to be the 4th warmest year on record."