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November of 2017 was the Third Hottest on Record Despite La Nina

According to NASA GISS, November of 2017 was the third hottest such month in the 137 year global climate record. This continues a trend of warming that began with fossil fuel burning at the start of the Industrial Revolution and that has recently hit new intensity during the 2014 – 2017 period.

NASA warming trend growing more extreme

(NASA color coded warming trend since 1901. Note the very extreme departures in the recent period since 2014. Image source: NASA GISS.)

Counting in November, 2017 is now solidly on track to be the second hottest year in the global climate record — trailing 2016 and edging out 2015. This new record was achieved despite the fact that La Nina emerged later in the year.

La Nina is a periodic cooling of Equatorial Pacific surface waters that also has a cooling influence over the Earth’s atmosphere when it emerges. The fact that we are on track to be experiencing the second hottest year on record, despite La Nina the cooling influence of La Nina which has been largely over-ridden, should be setting off at least a few warning lights.

Overall, temperatures for November were 0.87 C warmer than NASA’s 20th Century baseline and 1.09 C warmer than 1880s averages. Taking into account temperatures during early to middle December — which show a continuation of November ranges — it is likely that 2017 overall will average around 1.1 C warmer than 1880s averages once all the tallies are counted. Edging out 2015 by 0.01 to 0.03 C (see Dr Gavin Schmidt’s graph above).

By contrast, 2015 was a year in which the Pacific was ramping up toward a strong El Nino. So the La Nina signal for 2017 is important by comparison — validating numerous observations from climate scientists and climate observers that global temperatures have taken another step up (one of many due to human based heat forcing, primarily due to fossil fuel burning) without any indication of a step down.

(November 2017 sea surface temperature [SST] anomaly map at top shows evident La Nina pattern over the Equatorial Pacific. This should be creating a relative cooling signal. November 2015 SST anomaly map shows build up to El Nino type conditions. The fact that we will likely experience a warmer year in 2017 than in 2015 despite this contrast is a notable indicator for human-forced climate change and a continuing warming trend. Image source: NOAA.)

Regional analysis for November (see NASA map below) shows a very strong polar amplification signal with the highest Latitudes in the Northern Hemisphere displaying the most extreme temperature departures. Latitude 80-90 N showed the greatest zonal anomaly at around 5.5 C above average. While the global hot spot in NE Siberia hit an amazing 9.3 C above average for the month. Polar amplification was also more evident over Antarctica during the month with temperatures ranging from 1.5 to 2 C above average in the region of 75 to 80 S Latitude. This was significant given the fact that anomalous polar warming relative to past temperature trends tends to take a step back during late spring and summer months (it was late austral spring in November).

(Global anomalies map shows very extreme polar warming during November of 2017 with few regions of the globe experiencing below average temperatures. Image source: NASA GISS.)

It is worth noting that very few regions experienced temperatures below NASA’s 20th Century baseline. That regions experiencing temperatures below 1880s averages were even more scarce. And that the global cool spot at 4.1 C below average was less than half the amplitude of the most extreme warm departure (9.3 C).

The last time temperatures were globally below average during any month was in 1985. Which means that if you’re younger than 32, you’ve never experienced a below average month globally. Presently temperatures are so extreme now that globally below average single days are almost entirely a thing of the past. Warming has thus thrust us well outside the typical range of variability. And as a result, we are experiencing temperature, rainfall, fire, drought, snow, sea level, and storm conditions that are increasingly outside the norm, that are increasingly difficult to manage and adapt to. A trend that will continue so long as we keep burning fossil fuels. So long as the Earth keeps warming.

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