The World Meteorological Organisation says 2017 is set to be the warmest year without an El Niño occurence, since temperatures were first recorded in the late 1800s. There’ve been heatwaves in Chile, the Mediterranean, Southwest Asia and California; severe drought in East Africa, destructive floods in the Indian subcontinent, and a very active North Atlantic hurricane season. Dr Brett Mullan, the principal climate scientist at NIWA, says 2017 was meant to be a La Niña year, which tends to be cooler, but the record temperatures might herald changes to the way scientists categorise the systems.