“Even without El Niño, this would have been the warmest year on record.” Dr Gavin Schmidt, Director of NASA GISS, in a press conference today.
2015 was a historic year for global temperatures. A massive accumulation of greenhouse gasses pushing above 400 parts per million CO2 (and hitting in the range of 485 ppm CO2e) combined with one of the strongest El Ninos on record to spike global temperatures in every major climate monitor well beyond the 1 C above 1880s threshold. This marks the first time in the history of human civilization that temperatures have been so hot globally. A severe departure that moves our current world decisively out of the Holocene context and into hitherto uncharted territory.
(NASA Land-Ocean Temperature Index shows a historic record hot year for 2015. A trend line that speaks volumes for how much human-forced warming through fossil fuel burning has altered the world’s climate. Image source: NASA GISS.)
In the NASA monitor, 2015 beat out previous record hot year 2014 by a significant 0.13 C margin. A measure 0.87 C above the 1950-to-1981 NASA 20th Century base-line and fully 1.09 C above 1880s averages. Just one look at the graph above tells a stark story of raging global temperature increases — especially since 1980 where the average decadal increase is now solidly above 0.15 C every ten years.
NOAA’s own monitor tells a similar story with 2015 coming in at 0.90 C above the 20th Century average or about 1.12 C above 1880s averages. That’s just 0.38 C below the increasingly dangerous 1.5 C threshold and just 0.88 C below the very dangerous 2 C mark. If the current rapid warming trend in the global temperature graph were to merely continue, we’d pass the 1.5 C mark in less than two decades time and hit the 2 C mark within just 4-5 decades. That said, if an analysis by Dr. Michael Mann is correct, we could hit the 2 C mark by as early as the middle 2030s if we continue fossil fuel burning at such a ridiculously rapid rate.
Most Heat Concentrated Northward
Though 2015 was the hottest year on record, not all of that heat was evenly distributed. Though practically all of the globe experienced above average temperatures for the year, there were noted exceptions. Greatest above average temperature departures concentrated in the upper Latitudes of the Northern Hemisphere. Alaska, Western Canada, the Beaufort Sea, the High Arctic north of Svalbard, the Barents and Laptev Seas and most of Northern Continental Asia experienced extreme temperature departures in the range of 3 to 3.6 degrees Celsius above average. Exceptional heat in the range of 2-3 degrees Celsius above average also held sway over the Western United States and an area of warmth in the Northeastern Pacific dubbed the hot blob.
(2015 Showed a continued Northern Hemisphere Polar Amplification with regions near and within the Arctic showing the greatest above average temperature anomalies. Image source: NASA GISS.)
Though most of the world showed above average temperature readings, negative departures appeared in the region of the Southern Ocean just north of Antarctica and in the cool pool zone of the North Atlantic south of Greenland. During recent years, atmosphere to ocean heat transfer has been quite intense in the Southern Ocean — the upshot of increasingly powerful storms in the 50s and 60s South Latitude region. The North Atlantic cool pool has also been a persistent feature during recent years — one that is likely related to a weakening of the northward flow of the Gulf Stream, a weakening of overturning circulation in the North Atlantic, and an increased rate of glacial melt outflow from Greenland (as the current signal is stronger than traditional AMOC variability). So, ironically, both cool pools remain as ever more clear indicators that the global climate system is being driven out of balance by a rampant human emission of fossil fuels.
2016 — Third Hottest Year in a Row?
Looking ahead, it appears that 2016 may come in as yet one more hottest year on record. An event that, should it occur, would mark the first time in the global climate record that three back-to-back years set new global atmospheric temperature records (2014, 2015, and 2016).
Heat blowing off into the atmosphere from a record or near-record El Nino still likely hasn’t had its full impact. So the first 4 months or so of 2016 may see some very severe high temperature departures similar to or even higher than what we saw in December (1.42 C above 1880s for JMA, 1.34 C above 1880s for NASA, and 1.33 C above 1880s for NOAA). This probable early-year temperature spike for 2016 may be enough to carry the year forward as the new record holder given the fact that the current El Nino is expected to persist through late spring or early summer. So a record warm 2016 has better than even odds of occurring given the fact that the 2015-2016 El Nino was so strong and since it may hold on well into 2016.
More Warming in the Pipe
Longer term, the rate of greenhouse gas accumulation in the Earth atmosphere on the order of more than 2 parts per million CO2 each year and in the range of 3 parts per million CO2e does not at all bode well. As noted above, simply remaining on the current path of global temperature increase brings the world above 2 C in just 4-5 decades even as risks increase, given current levels of emissions, that the world could see 2 C worth of warming by the mid 2030s. And since greenhouse gasses are the driver in total of the current rampant global temperature increase, we should be very clear that rapid cuts to zero to net negative carbon emissions are necessary for the protection of human civilizations and for the protection of the life-sustaining capacity of the Earth itself.