Greenhouse gas concentrations hit a record last year and the world is "way off track" on capping rising temperatures, the United Nations said on Monday, showing the task facing climate talks in Glasgow aimed at averting dangerous levels of warming.

A report by the UN World Meteorological Organization (WMO) showed carbon dioxide levels surged to 413.2 parts per million in 2020, rising more than the average rate over the last decade despite a temporary dip in emissions during Covid-19 lockdowns...