2017 was the hottest year on record without an El Niño
Meteorologist/Science Writer
Friday, January 19, 2018, 12:42 PM - 2017 has now taken its place as one of the top three hottest years on record, despite the lack of any help from El Niño and even with a slight cooling influence from La Niña in place, thus providing even stronger evidence that our planet is rapidly warming due to human activities.
The official word is in on 2017 global temperatures, from both NOAA and NASA.
In a Thursday morning joint teleconference, the two agencies revealed their independent conclusions, after tallying global temperatures during last year, and comparing those tallies to all years going back to 1880.
Based on NOAA's records, 2017 is now ranked as the 3rd hottest year on record, at 0.84oC above the 20th century average, behind both 2016 (at +0.94oC) and 2015 (at +0.90oC).
The Year-to-Date tally of 2017, compared to the eight other warmest years since 1880. Credit: NOAA
NASA now places 2017 as the 2nd hottest year on record, based on its measurements, at 0.91oC above the 20th century average, behind 2016 (at +1.00oC), but ahead of 2015 (at +0.87oC).
The year-to-year temperature anomalies compared to the 1951-1980 average, ranks 2017 2nd warmest. Credit: NASA GISS
The differences between these records is due to the differences in temperature measurement coverage of the two agencies, and the statistical methods they use to compute the averages. However, even though these records vary from one another by a few hundredths of a degree, both agencies show the same long-term trend of temperature rise.
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These final tallies verify with the forecast from last year, as it became more and more clear that 2017 was not likely to beat out 2016, with its influence from a very strong El Niño, but it would certainly provide a serious challenge to 2015's spot on the list of hottest years on record.
Given that temperatures over Canada and the United States have been brutally cold so far this winter, it may be difficult to believe that 2017 still comes in as the 2nd or 3rd hottest year since the start of the Industrial Revolution. However, as the animation below shows, the cold here was vastly overwhelmed by the warming elsewhere in the world.
Hottest year without El Niño
El Niño is a pattern of very warm ocean temperatures across the eastern end of the equatorial Pacific Ocean. La Niña, its counterpart, is a pattern of extra warm ocean water at the western end of the equatorial Pacific Ocean, and extra cold water at the eastern end. These patterns have an influence on global temperatures, with El Niño bumping temperatures up and La Niña tamping them down, and by how much depends on how strong the pattern is. We saw the influence of the El Niño during 2015 and 2016, as NASA determined it added 0.04oC to 2015's overall temperature average, and added 0.12oC to 2016's average.
What's truly remarkable about 2017? It ranked as high as it did in the records even without the influence of an El Niño. Also, there was even a slight cooling influence in place due to the weak La Niña patterns that both started and ended the year.
To emphasize this, NASA climate scientist Gavin Schmidt presented an analysis that separated out the influence of El Niño and La Niña throughout the years. The analysis shows that if there had not been a 'super' El Niño in 2015 and 2016, those two years would have still ranked as #2 and #1 in the record books, respectively, as of the end of 2016. However, once 2017 was tallied, the top three years would have a slightly different order to them.
Global temperatures, compared to pre-industrial level (1880-1899). The black line represents the un-corrected temperatures. The red line represents the same data set, with the influences of El Niño and La Niña removed. The grey bars represent the cooling influence of major volcanic eruptions. Credit: NASA/Gavin Schmidt
As of now, 2016 is still officially the hottest year in the record books, going back at least 137 years, but very likely actually going back centuries. It would have achieved that record, at the time, without any help from El Niño. El Niño did boost the year's temperatures exceptionally high, though, so that it retains that title, even now.
2017, however, was the hottest year in the records that did not have any influence from El Niño, and it would have taken that title of hottest year, officially, if the 2015-16 El Niño had not happpened.
So, while the final tallies of the temperature records may put 2017 as the 2nd or 3rd hottest year on record, that - in no way - indicates that global warming is having any less of an impact. In fact, when we filter out the natural influences, we see just how strong the unnatural influences really are, and it becomes even easier to see how human activities are impacting the planet.
Editor's Note: This article was originally published on Thursday, January 18, but it has been updated, as of Friday, January 19, for clarity.
