No let up in global warming spiral, especially in the Arctic
Surface air temperature anomaly for October 2016 relative to the October average for the period 1981-2010. Source: ERA-Interim. (Credit: ECMWF, Copernicus Climate Change Service)
The average global temperature for October 2016 was 0.57 degrees Celsius above the 1981 to 2010 average, continuing a spell of “exceptional global warmth that has now lasted more than a year, according to the European Climate Change Service.
Global temperature anomalies topped out in February with the peak of El Niño, then declined in spring and rose again in summer, declining only slightly in September. The October departure from normal was only slightly lower in October, just 0.07 degrees Celsius under the all-time record for the month, set just last year.
With the exception of June, each month from October 2015 to October 2016 has been more extreme than January 2007, which was previously the month with the warmest anomaly. Each month from August 2015 to September 2016 successively became the warmest on record for that particular month.
October 2016 was cooler than the 1981-2010 average over much of Europe, but warmer than average in the far north of the continent and over the Iberian Peninsula and Mediterranean. Well-above normal temperatures also occurred over the USA and parts of Africa. Temperatures were most above normal over much of the Arctic and Antarctic, with record-low sea extent in both regions.
Temperatures were below average along the equator over the eastern Pacific Ocean, indicating weak La Niña conditions, over some oceanic regions of the southern hemisphere and over part of the North Atlantic. Other land areas with below-average temperatures include most of Australia, western and north-eastern Canada and much of the southern half of South America. The zone of below-average temperatures bounded north and south by above-average temperatures extended eastwards across Asia.
Averaging over twelve-month periods smooths out the shorter-term variations. Globally, the warmest twelve-month period on record is from October 2015 to September 2016, with a temperature 0.64 degrees Celsius above the 1981-2010 average.
Uncertainty in the global value is relatively high for the year 2005, but there is agreement between various datasets regarding:
- the exceptional warmth of 2016, and to a lesser extent 2015;
- the overall rate of warming since the late 1970s;
- the sustained period of above-average values from 2001 onwards.
There is more variability in average European temperatures, but values are less uncertain because observational coverage of the continent is relatively dense. Twelve-month averages for Europe have been at a persistently high level for the last three years or so. They are nevertheless lower than the averages from around the middle of 2006 to the middle of 2007.