Extraordinary ocean surface temperature anomalies that spiked into the range of + 1.4 C above 1880s values and a continued progression of the Pacific toward El Nino began to take its toll in April. NASA GISS shows that global temperature anomalies hit 0.73 C above the 1951-1980 average last month, the second hottest in the record and just behind 2010′s +0.80 C reading.
2010 was an El Nino year and the most recent record-holder for hottest year in the NASA measure. So it appears all it takes is just a slight tilt toward El Nino, as we saw in April, to challenge previous highs.
(Temperature anomalies for April of 2014 vs the 1951-1980 average. Image source: NASA GISS.)
The global hotspot for the month again centered on the Yakutia region of Siberia stretching south into Mongolia and Northern China and north into the East Siberian and Beaufort Seas. Positive anomaly values hit as high as 7.9 degrees C above average for the entire month in this hot zone. This was the same region that experienced anomalously intense wildfires throughout much of April and into early May with some fires burning along gargantuan fronts stretching 20 to 100 miles.
Alaska, Europe, North Africa, the Middle East, Queensland and West Antarctica also displayed very warm readings in the range of 2-4 C above average for the month. Meanwhile, positive sea surface temperature anomalies advanced into the Eastern Equatorial Pacific during April, a clear sign that ocean heat was beginning to transfer back to the atmosphere.
Negative temperature anomalies were confined primarily to the Hudson Bay region and to the High Arctic above 80 North in the Northern Hemisphere and in the Southern Ocean adjacent to Antarctica in the Southern Hemisphere. These cool zones were both small and isolated as most of the world experienced above average to well above average readings.
(Temperature anomalies by Latitudinal zone. Image source: NASA GISS.)
High latitude zonal anomalies in the Northern Hemisphere fell off with the arrival of Spring bringing down high temperature anomalies that occur as a result of polar amplification due to human-caused warming and ramp up during late Autumn and early-to-mid Winter. Cold air again retreated toward the pole where it will fight a battle with Summer heat over a diminishing ice cover. Warmth followed the cold retreat into high latitude regions, though, pushing heat anomaly values up to an extreme +2.7 in the region around 70 degrees North Latitude signalling the location of the warm-cold battle line for the onset of late Spring and early Summer. It is a line well north. One that includes sections of the Arctic Ocean now experiencing early melt and/or sea ice break-up.
With the onset of austral fall, polar amplification ramped up for the Southern Hemisphere with extreme low latitude Antarctica experiencing +1.45 C above average temperatures for the month.
Following March’s +0.70 above average reading, April showed continued progress toward warming. And with May seeing further advancement toward El Nino in the first and second week, we can expect global temperature values are likely to keep rising.