2019 poised to be one of the top three hottest years on record

Even as of October, this year is set up to become one of the hottest on record, and it could even be in the top two

There are still weeks left in the year, and thousands of temperature records to tally up before scientists can state, officially, where 2019 will stand in the climate record. Even so, it is looking more and more certain that it will become one of the hottest years on record.

In their October 2019 Global Climate Report, NOAA - the U.S.'s National Oceanic and Atmospheric Administration - already named the month as the second hottest on record. Only October 2015 was hotter, by the narrow margin of just 0.06°C. This was likely due to the influence of 2015's super El Niño.

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On this graph of October temperatures from 1880 to 2019, October 2019 ranks as 2nd hottest. Credit: NOAA

It may not have felt that warm to some in Canada and the United States, but the cold blob of air that settled in over regions for part of the month was an anomaly compared to much of the rest of the world.

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October 2019 temperature departures map. While there are some cool spots, and the one cold spot over western North America, temperatures in the rest of the world are all above the 30-year average from 1981-2010. Credit: NOAA

Two full months of data still need to be assessed for there to be a final word on exactly where 2019 will end up on the list of hottest years on record. Regardless, just based on what we have been seeing so far this year, it is not that difficult to get a sense of where the year will land.

Except for January of this year, each month has been at least 3rd hottest on record, so far. We saw the hottest June and July on record, with July even becoming the hottest month ever recorded, of all the months on record so far since 1880. September also tied with September 2015 as the hottest.

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NASA's year-to-date temperatures for 2019, compared to the rest of the climate record. Credit: NASA GISS

So, with temperatures running that high all year long, it simply comes down to how things could go from here.

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As it stands, the year-to-date monthly temperatures for 2019 already have the year pinned as the second hottest on record.

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This 'horse race' view of global temperatures compares 2019 to the top ten hottest years on record. Credit: NOAA

Unlike the NASA graph, which tallies each individual monthly temperature anomaly, this NOAA graph presents the year-to-date averages for each month.

"In other words," says NOAA, "the January value is the January average temperature anomaly, the February value is the average anomaly of both January and February, and so on."

That makes it easier to see each year's line as a trend, and it makes it more difficult for any particular line - especially this far along in the year - to see a significant departure from that trend.

According to NOAA, while there is less than a 0.01% chance of 2019 becoming the warmest year on record (2016 is going to keep that record for now), they are 99.9% certain that this year will be in the top five hottest. This is not much of a stretch, considering that the five hottest years on record have occurred within the past five years. NOAA's current ranking are 1st: 2016, 2nd: 2015, 3rd: 2017, 4th: 1018, and 5th: 2014.

Narrowing it down even further, from there, they say there's a 95% chance that 2019 will be 2nd or 3rd warmest year on record. Given the graph above, and how the 2019 year-to-date trend line is progressing, that's easy to see.

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Where will the year actually fall though? Their data, as of October, is pointing with over 85% certainty towards 2019 displacing 2015 from its spot as the 2nd hottest year on record.

Source: NOAA Global Climate | NOAA Global Annual Temperature Rankings Outlook