Guardian: The planet is warming at a pace not experienced within the past 1,000 years, at least, making it “very unlikely” that the world will stay within a crucial temperature limit agreed by nations just last year, according to Nasa’s top climate scientist. This year has already seen scorching heat around the world, with the average global temperature peaking at 1.38C above levels experienced in the 19th century, perilously close to the 1.5C limit agreed in the landmark Paris climate accord. July was the…