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World Climate Stays in Uncharted Territory as May of 2017 Hits Second Hottest on Record
19
June, 2017
We’re
currently in what should be a relatively considerable temperature
trough following a strong 2015-2017 El Nino. But
the globe hasn’t really cooled off that much.
In
contrast, during the two year period following the 1998 super El
Nino, annual global temperature averages subsequently cooled by
around 0.2 C to about 0.64 C warmer than 1880s averages as a strong
La Nina swept in. This post El Nino cooling provided some respite
from harmful global conditions like increasingly prevalent droughts,
floods, fires and coral bleaching events set off by the 1998
temperature spike. It did not, however, return the world to anything
close to average or normal temperature conditions.
Warming
Out of Context
(So
far, 2017 temperature averages for the first five months have
remained disturbingly close to what should have been an El Nino
driven peak in 2016. Temperatures remaining so warm post El Nino are
providing little respite from this peak warming. Meanwhile, the
longer La Nina conditions hold off, the more extreme and out of
context the post-2013 period looks from a global weather/climate
perspective even relative to the significant warming occurring from
the late 1970s through the early 2010s. Note the steep temperature
spike following 2013 in the graph above. This should flatten out,
step-wise, as La Nina conditions ultimately push against the larger
surface warming trend [driven primarily by fossil fuel burning]. We
thus await La Nina with baited breath… Image source: NASA.)
During
2015 and 2016, the world was forced to warm much more intensely than
during the 1998 event as very high and rising greenhouse gas
concentrations (400 ppm CO2 +) met with another strong El Nino and
what appeared to be a very widespread ocean surface warming
event. Temperatures
peaked to a troubling 1.2 C hotter than 1880s averages during 2016.
An annual peak nearly 0.4 C warmer than the 1998 temperature
spike. But
unlike the period following the 1998 event, it appears that 2017 will
probably only back off by about 0.1 degrees Celsius at most.
This
counter-trend cooling delay is cause for some concern because a
larger portion of the global surface heat added in during the
2015-2016 El Nino appears to be remaining in the climate system —
which is lengthening some of the impacts of the 2015-2016 temperature
spike and putting the world more firmly outside of the weather and
climate contexts of the 19th and 20th Centuries.
(2017
temperatures aren’t trailing too far behind 2016’s record spike.
A trend that is, so far, considerably warmer than 2015, which was the
second hottest year on record. Image source:NASA.)
Record
heat, drought, rainfall events, unusual storms, coral bleaching,
glacial melt, wildfires, sea ice melt and other effects related to
extreme global temperature will, therefore, not abate as much as some
would have hoped. Furthermore, though current science does not appear
to identify a present perturbation in the ENSO cycle (which may
produce more El Ninos as the world warms), monitoring of that cycle
for warming-related change at this time seems at least somewhat
appropriate.
Second
Hottest May on Record
According
to NASA,
May of 2017 was 0.88 degrees Celsius hotter than its 20th Century
baseline — or 1.1 C warmer than 1880s averages when the world first
began a considerable warming trend clearly attributable to fossil
fuel burning and related human carbon emissions. This reading is just
0.05 C shy of the record warmest May of 2016. It’s also slightly
warmer than the now third warmest May (0.01 C warmer) of 2014. And
all of the top four warmest Mays in the present NASA record have now
occurred since 2014.
(NASA’s
second hottest May on record brought above normal temperatures to
much of the globe. Disturbingly, the most extreme temperature
departures above average occurred in the vulnerable Coastal regions
of Antarctica. Small regions including parts of the North Pacific,
the Northern Polar Region, the extreme South Atlantic, and the
Central U.S. experienced below average temperatures. But these
outliers were few and far between. Image source:NASA.)
Add
May of 2017 into the present 2017 running average and you get a total
of 1.19 C warmer than 1880s conditions. This is the second warmest
first five months on record following 2016 at a
very considerable 1.38 C above 1880s.
It is, however, just about 0.01 C behind 2016’s annual average of
1.2 C above late 19th Century global temperatures.
It’s
worth noting that most of the temperature spike attributable to the
2015-2016 El Nino occurred beginning in October of 2015 and ending in
April of 2016. Somewhat milder months comparable to April and May
2017 averages followed from June through December of 2016. So a
continuation of present trends could leave 2017 rather close to the
2016 spike.
Forecast
Trends
GFS
model guidance for June shows somewhat cooler global conditions than
in May. If this trend continues we will likely see the month range
from 0.7 to 0.82 C above NASA’s baseline. If the GFS summary is
accurate and this meta-analysis is correct, then June of 2017 will
likely range between 1st and 4th warmest on record. Meanwhile, ENSO
(El Nino Southern Oscillation) neutral conditions should tend to keep
2017 as a whole in the range of 1.07 C to 1.2 C hotter than 1880s
averages — beating out 2015 as the second hottest year on record
and keeping the globe in what basically amounts to uncharted climate
territory.
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