There are three months left in 2015, and it’s all but certain this year will go down as the world’s hottest on record. Oh, and 2016 is likely to follow suit.



A 1-2 punch from NASA and the U.K. Met Office, two of the world’s leading climate institutions, show how much the heat is on for planet. On the NASA side, data published earlier this week show this past August was the second-hottest on record and that it was 1.5°F above the monthly average. And barring a sudden run of cool months to end the year, that leaves 2015 on track to be the hottest on record, ousting 2014.

But cooler-than-normal temperatures are unlikely, thanks in large part to El Niño, the climate phenomenon on the tip of everyone’s tongue. The warm waters across the central and eastern tropical Pacific are boosting global temperatures, which is on top of the long-term warming driven by human greenhouse gas emissions.



This El Niño is one of the strongest on record and is likely to persist into spring next year, which should keep the globe running hot. The U.K. Met Office has indicated that the planet will stay warmer than normal through 2016.

El Niño is one factor. Climate change is another. But there’s a third climate player that could bring widespread heat in 2016.

That is the Pacific Decadal Oscillation (PDO). It’s a pattern of ocean temperatures in the Pacific that has a warm and cool phase. The PDO has been in a cool phase for the past decade and some research has tied that to the global warming slowdown over that time.



Chance of a record warm year in the 2015 GISTEMP index have increased to 87%. pic.twitter.com/29AoeNwC9u — Gavin Schmidt (@ClimateOfGavin) September 14, 2015



The U.K. Met Office indicates a shift to the warm phase could be around the corner. While phase changes of the PDO are notoriously hard to predict, that shift could herald a period of rapid warming not just for next year, but for years to come.

A PDO-like pattern is beginning to emerge in the northeast Pacific where a pool of warm water — dubbed “the blob” — has dominated that portion of the ocean for more than a year.

With a positive PDO working in concert with manmade climate change, the U.K. Met Office has warned that the world could return to a period of rapid warming. A volcanic eruption or sudden, strong La Niña are two of the only likely factors that could put a damper on the U.K. Met Office projections.

“We know natural patterns contribute to global temperature in any given year, but the very warm temperatures so far this year indicate the continued impact of increasing greenhouse gases,” Stephen Belcher, the head of the Met Office’s Hadley Center, said. “With the potential that next year could be similarly warm, it’s clear that our climate continues to change.”