2017: another record-breaking year for heat and extreme weather

More record-breaking heat was experienced around the world in 2017, with the year joining 2014, 2015 and 2016 as the four hottest years ever recorded in the 138-year global temperature archive. In fact, 2013-2017 was the hottest five-year period on record. This recent record heat is part of a long-term global warming trend that began most clearly in the mid-20th century and has continued unabated since then. The world’s 10 hottest years on record have all occurred since 1998 and 17 of the 18 hottest years on record have occurred this century.