The world is now well on its way to seeing back-to-back hottest years on record. Unprecedented and amoral burning of fossil fuels is now forcing the global temperature average to rise into the range of 1 degree Celsius above 1880s averages — or halfway to a catastrophic 2 C warming. A level at which scientists believe many climate change tipping points will be irrevocably crossed.
June, July, August Were Hottest On Record
According to NASA GISS, global temperatures for the June, July and August period of 2015 were 0.78 degrees Celsius (C) above the 20th Century benchmark or about 0.98 C above 1880s averages — when global record keeping began. The previous hottest three month period occurred during 1998 at +0.72 C. Notably, June, July and August were the hottest three months for 1998. But for 2015, December, January and February came in at +0.83 C and March, April and May came in at +0.81 C. These extreme temperature departures, when combined with the June, July and August readings, now put 2015 at +0.80 C above average for its first 9 months — or well above any previous record-breaking year. A significant single year margin above the previous hottest year — 2014 — of +0.05 C (a single year rate of warming about 150 times the average rate of warming at the end of the last ice age).
(NASA GISS spatial anomalies map for August of 2015. Image Source: NASA)
August of 2015 Comes in As Second Hottest Amidst Global Warming And El Nino Signature Temperature Anomalies
August itself came in at +0.81 C above NASA’s 20th Century benchmark average. This departure marked the second hottest August reading in the 135 year temperature record, falling just 0.01 C behind the previous hottest August reading hit just last year (2014).
Geographic distribution of temperature anomalies continue to show the signatures of both a strong El Nino and a growing climate change related signal. The August El Nino signature was particularly strong in the Eastern and Central Equatorial Pacific with 1-4 degree Celsius hotter than normal temperature departures dominating the region. This heat extended throughout the anomalous ‘Hot Blob’ or ‘Ridiculously Resilient Ridge’ zone that has continued to be dominated by extreme sea surface temperature departures with 1-4 degree Celsius above normal temperatures pervading. Such extreme heat was linked to equally extreme drought and wildfire conditions dominating broad sections of the North American west throughout the month. Conditions that, for many areas, have been endemic for many months running.
Anomalous heat also dominated the land masses of South America, Europe, South Africa, and the Lake Baikal region of Russia. These areas experienced some or all of the following: extreme drought, wildfires, water resource stresses, extreme heat-related weather, and heatwaves. A cool pool in the Northern Atlantic between England and Newfoundland remained a prominent feature. This cool region is associated with climate change related conditions that are now in the process of weakening both the Gulf Stream and North Atlantic bottom water formation. It’s a set of conditions that weakens equator to mid-latitude heat transport and intensifies the North Atlantic storm track. An upshot of human-forced warming that has been predicted for decades by even the most rudimentary of global climate models but that now appears to be cropping up a bit earlier than previously expected (see World Ocean Heartbeat Fading?). Persistent troughs over Eastern North America and Western Russia also generated their own cool pools. Meanwhile, surface temperatures over Central Antarctica dipped into cooler values — likely associated with intensification of storm systems in the Southern Ocean.
(NASA zonal temperature anomalies show a signature consisted with strong El Nino and related equatorial warming. Image source: NASA GISS.)
NASA’s zonal anomalies map also displayed a strong El Nino signature with the global equatorial zone showing the highest above average temperature departures (in the range of +1.3 degrees Celsius). This extreme heat maintained throughout the Northern Hemisphere mid-latitudes all the way to 60 North before falling off to between +0.2 to +0.4 C near the pole. Progressing southward, anomalies steadily declined, even dipping into a range of 0 to -0.9 C anomalies in the region of 75 to 90 South.
Conditions in Context — Record High Temperatures and Related Extreme Weather in the Pipe
Consistent high temperature departures near the Equator, as we see now, tend to aid both in storm track intensification and a general flattening of the Jet Stream. Though these conditions have not yet dominated in the Northeastern Pacific, a continuation of the August temperature departure pattern and related strong El Nino will likely both intensify the Northeastern Pacific and North Atlantic storm tracks as Fall progresses. Such a shift, however, would have to be very extreme to bust the 3 year running California Drought.
Overall temperature departures for both August and for the June, July, August period are well outside the range of anything that could be considered normal and are swiftly rising to more and more unsafe and climate destabilizing levels. The emergence of the North Atlantic cool pool is a feature specifically related to storm intensification and regional and global weather destabilization. A feature predicted by global climate models due to human forced warming, related melting of Greenland ice, and the upshot slowing down of critical ocean currents. The recent unprecedented Hot Blob in the Northeastern Pacific was likewise predicted in the scientific research as a result of human forced warming — a feature that, it was warned, could result in much warmer and drier conditions for the North American West Coast. Climate change related heat signatures such as these clearly show in the NASA monitor even as the global measure keeps rising to new and more dangerous extremes.
(Please support public, non special interest based, science like the fantastic work done by NASA’s GISS division and without which this report and related analysis would not have been possible.)