The title is a bit of a pun, since it refers to both the “big 3” global temperature data sets — NASA, NOAA, and HadCRUT4 — it also refers to the third year in a row global temperature has set a new record.
NASA and NOAA held a joint press conference to announce their latest results, and HadCRU released their data at the same time. While the “third record-hot year in a row” may be what gets the most airtime and column inches, it’s the continuing trend (which has been ongoing for 40 years) that’s the real story.
The recent strong el Niño contributed to the extremity of this year’s record, but we’ve had strong el Niño events before. The reason this one beat the pants of all those previous el Niño years is the trend, the persistent warming of the planet caused by greenhouse gases. Also known as: global warming. Anybody who tells you different, is selling something.
If we estimate the influence of factors besides global warming, things like el Niño, volcanic eruptions, and solar variations, the overall trend becomes more clear but the extremity of 2016 is reduced. For NASA data (since 1951), the unadjusted data look like this:
But after adjustment we get this:
Unadjusted NOAA data:
Adjusted NOAA data:
Note that when we allow for non-greenhouse factors, only NASA data still show 2016 as the hottest year on record. That’s because they all treat the Arctic differently. NASA does the most detailed estimate of Arctic temperature, while HadCRU simply leaves it out — but since the Arctic warmed so much last year, leaving out the fastest-warming region on Earth of course makes your global estimate an underestimate.
And what did happen to the Arctic? This:
The yearly average Arctic temperature was an amazing 1.4°C hotter than the year before, and an astounding 1.02°C hotter than any previous year.
What happened to Earth’s overall temperature last year was shocking. What happened to the Arctic was beyond shocking. There will be consequences.
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