After a summer of record-smashing heat, warming somehow got even worse in September as Earth set a new mark for how far above normal temperatures were.
Antonio Guterres delivered the comments on the sidelines of the UN General Assembly, as politicians, as well as activists, business and civil society leaders met for the summit.
Labour Day on Monday was the hottest day on record so far this year at 34 C in Toronto, surpassing a very warm June 2 at 32 C, according to data from Environment Canada.
The early September heatwave comes to London and Middlesex as daytime highs are set to reach 31C to 35 C, with the hottest days expected to be Tuesday and Wednesday.