Man, it’s a hot one. And by “it” we mean 2016. Reports issued this week by NASA [PDF], NOAA, and the UK Met Office have all concluded that 2016 was the hottest year on record, beating out the sweltering temperatures of the prior two years—which were also record breakers.
Experts have been taking our planet’s temperature every day since the late 1880s. Longer-term models and projections suggest that the last time Earth got this hot was about 115,000 years ago [PDF].
Last year saw an eight-month stretch of record-high global temperatures from January to August, and all low temperatures met or exceeded the 20th-century average. Sea ice shrank and water levels rose.
Climate scientists like Michael Mann of Penn State University say there can be no doubt about the cause. “The effect of human activity on our climate is no longer subtle,” he told The Guardian. “It’s plain as day, as are the impacts—in the form of record floods, droughts, superstorms, and wildfires—that it is having on us and our planet."
Participants in 2015's Paris accord agreed on the importance of limiting further climate change, and set a maximum cap of a 1.5°C increase in average temperature. We’re currently at 1.1°C.
The time to act is now, says NOAA’s Kevin Trenberth, who says that those who oppose environmental protections for financial reasons would be wise to reconsider. “While there may be some cost in mitigating climate change,” he told The Guardian, “there are already major costs in damages.”
Appealing directly to lawmakers’ wallets, Trenberth argues that “sensible approaches” to cutting emissions and boosting climate resilience “can actually make it a net gain, not only for the planet [but] for everyone.”