Record temperatures in September

Global Temperatures Smash September Record by Widest Margin in History

Eric Holthaus

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Slate,

21 October, 2015

Powered by a huge El Niño and decades of fossil fuel burning, last month’s global temperatures were truly exceptional, according to new data from the National Oceanic and Atmospheric Administration.

September 2015 broke the monthly global temperature record by the widest marginof any month since 1880, when records begin. The magnitude of this month’s record, combined with the fact that seven months so far this year are now the hottest in history—including the last five in a row—means 2015 is now virtually certain to wind up as Earth’s hottest year ever measured.

Stories on these broken records increasingly sound like—wait for it—a broken record, so we’re writing fewer of them at Slate unless something truly exceptional happens. This month definitely qualifies.

El Niños like this one have the ability to shift weather patterns on a global basis and in general send a surge of extra heat into the atmosphere from the warmer-than-normal tropical Pacific Ocean. So far, the 2015 El Niño has been neck and neck with the all-time strongest event ever measured, back in 1997. One of my weather textbooks in college was titled The Climate Event of the Century in reference to that El Niño. It’s something you don’t really expect to see again in your lifetime.

There’s good reason to believe this year’s El Niño will keep strengthening, at least in the near term, with a litany of impacts worldwide. Several notable effects have already been recorded, in addition to the unprecedented spike in global temperatures:

• So far this year there have been 21 tropical cyclones of category 4 or 5 strength north of the equator—a new all-time record. Twenty of these have been in the Pacific, where El Niño tends to create exceptionally favorable conditions. TheWashington Post’s Jason Samenow described it as “the most extreme tropical cyclone season on record in the Northern Hemisphere.”
  
  
• Last week, a torrential rainstorm the National Weather Service described as a thousand-year rainfall event created a horrific mudslide that buried California highways, trapping hundreds of cars. Those near the scene described it as a “wall of mud.” No one was seriously hurt.
  
  
• Earlier this month, much of Australia dealt with a brutal spring heat wave that likely reduced farmers’ yields. Australia is typically one of the countries hit hardest by El Niño.
  
  
• In Indonesia, a huge burst of peatland wildfires has blanketed cities across the region with dense smoke for weeks, producing more daily carbon dioxide emissions than the entire United States. Also, new research shows a spike in dengue fever outbreaks in Southeast Asia during particularly strong El Niño years.
  
  
• A rare and venomous yellow-bellied sea snake was recently spotted on a beach in California, the furthest north sighting ever recorded, thanks to the warm water. But don’t worry, it’s probably nothing.

On the bright side, the wild weather could be a ratings boon for the flagging Weather Channel.

Whatever happens, there’s a very good chance that 2016 could top 2015 as the warmest year in history. Since it takes several months for all the oceanic heat to be released into the atmosphere, the year after an El Niño is usually the hotter of the two. Earlier this year, I wrote that a perfect storm of the current mega–El Niño combined with a medium-term shift in Pacific Ocean temperatures and the long-term climate change trend means that we’re likely at the start of a profoundly new era of the global climate