It’s the amount of warming past pre-industrial times that the IPCC says we should try to avoid this Century in order to prevent the worst consequences of human-caused climate change. It’s the so-called safe limit, even though there’s nothing really safe about it and we should probably be aiming more for a below 1.5 C target.
It’s the amount of warming between pre-industrial times and, according to the latest data from NASA, the first half of 2015. In other words, temperatures during the first six months of 2015 are now at least halfway toward freeing some of the nastiest climate monsters in the closet.
* * * * *
According to NASA GISS, June of 2015 was tied with 1998 as the hottest of any June in the entire 135 year global climate record. Coming in at +0.76 C above NASA’s 20th Century average, June follows May at +0.73 C (4th hottest), April at +0.71 C (tied for 3rd hottest), March at +0.91 C (second hottest), February at + 0.89 C (hottest), and January at +0.81 C (2nd hottest).
Combined, these average out for a +0.80 C departure from the 20th Century in the NASA measure. That’s an extraordinary amount of heat — +0.18 C above 1998 levels and +0.05 C above 2014, which was the previous hottest year on record.
But, perhaps most importantly, this reading is the first consistent break at 1 C above 1880s levels. An ominous benchmark and halfway to the catastrophic 2 C warming we really, really want to avoid.
June Takes On El Nino-Type Temperature Pattern
(NASA’s geographic temperature anomalies for a record hot June in 2015. Image source: NASA GISS.)
Looking at the June temperature anomaly map, we find very large zones of 2-4 C above average readings running up toward the Northern Hemisphere Pole. The first of these zones rides up over Western Asia. Covering most of the region from the Caspian Sea on northward, this area features two anomalously hot zones ranging to as high as a +4.7 C anomaly in intensity. The second of these zones issues from the developing El Nino in the Eastern Pacific, rides up over the hot ‘Blob’ of ocean water in the Northeastern Pacific, invades Alaska and the Pacific Northwest, and then enters the Beaufort and Chukchi seas. This zone also features large expanses of +2 to +4 C above average temperatures.
Overall, most of the globe saw above average readings with only the region just south of Greenland, a small zone just west of the hot ‘Blob,’ and an area of somewhat cooler readings over West Antarctic showing below average readings.
(Zonal anomalies began to pick up the El Nino signal during June. Note that equatorial heat gain nearly matches that of the Northern Hemisphere pole. Image source: NASA GISS.)
Under El Nino — a climate condition the globe is steadily transitioning toward — we would expect to see relative warming near the Equator and relative cooling near the poles. During June, we begin to see this signature with the Equator warming up to a substantial +1.2 C positive anomaly. Antarctica also followed this trend as that polar zone dipped into the -0.4 to -1.2 C negative anomaly range (60 to 90 South). Meanwhile, the Northern Hemisphere Polar zone (60 to 90 North) showed significant hot readings in the range of +0.9 to +1.4 C anomalies.
Overall, the entire globe from 50 South on northward experienced above average to much hotter than average temperatures in the zonal measure. A clear and powerful heat signal for June of 2015.
Building El Nino Likely Means More Heat to Come
With the first six months of 2015 finished and with El Nino still strengthening in the Pacific, it appears that a record hot year may already be a lock. In addition, further warming may be in store.
The current El Nino appears to be roughly on a similar development track, as far as timing and possible intensity, to the 1997-1998 El Nino. Given this rough allegory, we are approximately at the same place, climatologically speaking, as July of 1997. During that event, global temperatures didn’t really start taking off into severe record high ranges until Fall of 1997 through Summer of 1998. If the ocean to atmosphere heat loading for the current event proceeds in similar fashion, we could expect to see even more extreme temperatures than we are currently experiencing by Fall and running on through at least the first season or two of 2016.
(Record-breaking El Nino by October? NOAA CFSv2 models have been spitting out some pretty extreme results. If we see anywhere near this level of sea surface warming the Central Pacific, the heat records thus far for months during 2014 and 2015 may soon be left in the dust. Image source: NOAA CPC.)
Looking toward July’s forecast, there is a bit of a caveat. That month is typically cooler globally due to a lessed impact of the greenhouse gas heat forcing. This is due to the fact that greenhouse gasses are concentrated most heavily in the Northern Hemisphere and such greenhouse gasses are most efficient at heat trapping during night time and winter. As such, we may see a bit of a dip in the July readings below June. But if this current El Nino gets involved as the models predict, it’s likely to be record-breaking heat that pushes some very ominous global temperature thresholds all the way through from August 2015 to at least early 2016.
Let’s just hope we don’t close too much more of the gap to 2 C. It’s really starting to get scary out there.
Hat tip to Wili
(Please support public, non-special interest based, science like the fantastic work written about here and conducted by the experts at NASA and NOAA.)