NASA, NOAA: 2017 the 2nd or 3rd warmest year on record (after 2016), despite La Niña

My very first blog post on this website, almost exactly a year ago, was about the then-recently released data from NASA and the National Oceanic and Atmospheric Administration (NOAA) that independently confirmed 2016 had become the third consecutive year to set the record for warmest global temperature. My 2017 New Year’s resolution had been to learn more about global warming, whether the science was settled or not, and how (in some detail) we know, and to post my learning journey on this site. Over the course of the past year, I’ve learned a lot. I’ve learned the science is very settled, and I’ve learned exactly how long we’ve known global warming is real; as it turns out, we’ve had reliable measurements since 1958 that confirm suspicions and preliminary data scientists had since the late 1800’s (read a brief history, with links to the original research, here). I’ve learned about a multitude of easily observable effects of climate change that are happening right Before Our Eyes (check them out here). I’ve learned that we have readily available technological solutions, but we are not using them with anything like the urgency we need to if we want to prevent terrible future consequences.

A year later, the data from 2017 is in, and it was either the 2nd (according to NASA’s analysis) or 3rd (according to NOAA’s analysis) warmest year on record. Check out the press release for more details, and watch the NASA video below.

This is despite the onset of La Niña, a cyclical cooling of sea surface temperature across the equatorial Eastern Central Pacific Ocean, during the latter part of 2017, which tended to make the atmospheric temperature during that time cooler than average. El Niño, the warmer part of that Pacific cycle, was in effect for most of 2015 and the first third of 2016.

According to NASA, in an analysis of global temperature statistically removing the effects of El Niño and La Niña, 2017 would be the warmest year on record.

Why the difference in rankings between NASA (2nd warmest year on record) and NOAA (3rd warmest year on record)? As I explained in some detail on another page, NASA and NOAA are among four scientific groups (the other two being a British group and a Japanese group) that independently track global average temperature trends. While NASA, NOAA, and the other groups’ analyses have agreed remarkably well over the entire period between 1880 and now, they each use slightly different data sets and analytical methods. Specifically, NASA’s methods weight measurements in the arctic slightly more heavily than NOAA’s methods, and the arctic atmosphere has been warming more quickly than the global atmosphere as a whole.

In any case, all analyses agree that the past 3 years — 2015, 2016, and 2017 — were the hottest 3 years at least since 1880, when global temperature measurement became possible.

I guess we’d better keep learning about this, huh?

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