According to NASA’s most recent global land and ocean surface temperature survey, September of 2013 was .74 degrees hotter than the 20th Century average. This measure ties September of 2005 as the record hottest. The difference between 2005 and 2013? 2005 was an El Nino year. A year when a large swath of the Eastern Pacific was dumping its heat content into the atmosphere. This year, the Eastern Pacific has remained somewhat cooler than normal, sucking a degree of atmospheric heat out and dumping it into the deeper oceans. But, despite what would normally be a drag on global surface heating, the world’s temperatures where the air contacts the land and the sea remain at or very near new record highs.
This situation is not cause for comfort or complacency. Nor is it one that indicates what has been termed a so-called ‘pause in global warming’ by so many ill-informed in the media. To the contrary, what we are seeing is that the natural variation of El Nino to La Nina — variations that for centuries and millenia have primarily governed to world’s periodic warm and cool spells — is slowly being overwhelmed by the human greenhouse gas forcing. What we are witnessing is ENSO neutral and La Nina years and months coming very close to and reaching record hottest temperatures.
So the rhetorical question we should all be considering is this: if we are experiencing record high temperatures now, when the Eastern Pacific is relatively cool, what happens to the global record when ENSO again starts to heat up? And, in any case, ENSO or no, it appears increasingly clear that more new record warm years are now in the offing.
NOAA Shows Global Temperatures at 4th Hottest
NOAA’s own set of temperature measures also show record heat, with worldwide temperatures ranging 4th highest for the month. The NOAA reading, which varies slightly to the NASA reading due to a difference in measurement methodology, follows a June measure in which the world ocean system tied 2010 for hottest on record.
(Image source: NOAA)
NOAA’s global temperature map found hotter than average readings covering much of the globe throughout September. Record hottest regions blanketed Australia, Iran and Afghanistan, a large section of the Arctic Ocean north of Scandinavia, and smaller, more isolated patches around the globe. No region experienced record coldest temperatures. The only concerted regions experiencing cooler than average temperatures include a section of Siberia and Central Russia, and a region of the Southern Ocean between South America and Antarctica. The Eastern Pacific, which drives ENSO, remained cooler than surrounding waters at near or just below the 20th Century average.
Between the NOAA and the NASA temperature measures, it remains clear that record or near record warmth continues to dominate the global climate with pools of hottest ever recorded temperatures continuing to drift over the world. Given the increasing warmth, despite no El Nino, it appears possible that, should El Nino not arise within the next 3-5 years (unlikely given a long history of variation), the world will achieve new record warm years without it. And such an event would be yet one more that is without precedent.
Too Soon to Call For El Nino’s Return
(Image source: NOAA)
A pool of slightly cooler than average water over a moderate stretch of the Eastern Pacific during early November belies a continuing trend of ENSO neutral or La Nina leaning conditions. This pattern has dominated throughout much of the past two years and, currently, shows few signs of abating. As one can see from even the most cursory analysis of the image above, the global ocean system, despite the slight coolness in the Eastern Pacific, remains significantly warmer than the already warmer than average period of 1971-2000 which provides the base set for the above NOAA graphic.
The Hot Late Summer/Early Fall Arctic
One final driver to global heating during the months of September and August of 2013 appears to be a very warm late summer and early fall Arctic. Temperatures between the latitudes of 65 and 75 degrees North have been particularly warm with near record hottest and record hottest temperatures experienced in Scandinavia, regions of the Arctic Ocean north of Scandinavia, high north-west Canada, and Alaska. The Arctic Ocean in a zone between 70 to 75 North has experienced much warmer than normal conditions as sea ice remains between 4th and 6th lowest on record in all the various measurements.
Meanwhile, temperatures above the 80 degree North Latitude line, though not hitting the same record variances are regions nearer the Arctic Circle, showed temperatures ranging between 2 and 5 degrees Celsius above average for the months of September and October. This dumping of ocean and land heat into the Arctic environment, which slows the cooling of the Northern hemisphere into winter, has become an increasingly dominant weather phenomena over the past 5 years. It is also an event that has coincided with record loss of sea ice which has become particularly pronounced since 2007, with some years showing as much as 80% loss of sea ice volume and more than 50% losses of sea ice area and extent since 1979.
The resulting cooling lag in the Arctic during the months of August, September, October and November have, likely contributed to near record warm months globally during August and September of 2012 and 2013, despite La Nina or ENSO neutral conditions. This somewhat ominous signal shows that ENSO is in the process of gradually being over-ridden by other factors.
Climate models have indicated that the Arctic would be the first section of the globe to experience very rapid and pronounced warming under human greenhouse gas forcing and the related and powerful feedbacks of Arctic albedo loss and environmental greenhouse gas emission (methane and CO2). And with summer Arctic temperatures, in some regions, measuring their hottest in more than 40,000 years and with worldwide CO2 levels pushing toward their highest levels in 3 million years, it appears we are, sadly, at just the very beginning of such a dangerous and powerful warming trend.