Saturday, 24 September 2016

La Nina Fizzles, Pacific Hot Blob Returns

La Nina Fizzles, Pacific Hot Blob Returns, Record Global Heat Likely to Remain

A change of three degrees [Celsius] is an “extraordinary deviation — something you would expect to happen once in a millennium.” 

34 September, 2016

Four degrees Celsius. That’s the current deviation from the 1981 to 2010 average for sea-surface temperatures over a broad region of the northeastern Pacific, a deviation you typically wouldn’t see once in a thousand years.

During 2013 to 2015 a similar warm-up over this same region of water occurred. Such extreme heat at the ocean surface generated mass loss of sea life. Numerous species from plankton to krill to copepods to starfish and many more on up the food chain were impacted. This great ocean warming also sparked losses of ocean oxygen off Oregon and Washington, pushing waters there into low-oxygen and anoxic states. These states, though they do not support advanced ocean life, tend to support anaerobic microbes that produce various toxins (including hydrogen sulfide gas). At the same time, atmospheric circulation was also impacted, resulting in unprecedented drought conditions for California as a ridiculously resilient ridge of high pressure settled in.
(Region of the northeastern Pacific about the size of the state of Washington shows ridiculously hot sea-surface temperatures in the range of 4 C above average. Such once-in-a-thousand-years ocean-surface heat has now occurred for three out of the past five years. As end 2016 nears, this unprecedented blob of hot ocean-surface waters appears to be returning. Image source: NOAA ESRL.)

Such a terrible blow to ocean health combined with ever-more-extreme atmospheric conditions are the very hallmarks of a heating climate. As a result, the events associated with the 2013-2015 hot blob will likely, in future years, be seen as one of the warning shots across North America’s bow — an indication that climate change-related impacts were about to seriously worsen.
Hot Blob Re-Forms as La Nina Splutters

Now, after a one-year hiatus, the hot blob is back and northeastern Pacific sea-surface temperatures are again on the rise. A previously-predicted La Nina is abruptly spluttering out, apparently crushed by a periodic warming of the northeastern Pacific called the Pacific Decadal Oscillation (PDO). This natural variability-related feature is combining with climate change-induced ocean warming to again push ocean surface temperatures into unprecedented ranges.

(The northeastern Pacific hot blob is a climate change-related feature that contributes to record heat, drought and wildfire risk for California. Over the coming week, the re-formed hot blob appears ready to plunge the state into 90 to 1oo degree (F) conditions — which will intensify wildfire risk for the state. Image source: Pivotal Weather.)

With the PDO again firing up, the hot blob re-forming, and La Nina starting to splutter, we can expect global temperatures to remain closer to the record-hot levels achieved during 2015 and 2016. This is bad news in that 2017 through 2022 might see another record-hot year coordinate with El Nino, which would push even closer to 1.5 C and 2 C climate thresholds — a clear sign that the age of fossil fuel exploration and burning needs to end as swiftly as possible if livable climate conditions are to be maintained.
Nearer-term, if this heat in the northeastern Pacific remains in place, we can expect worsening hot and dry conditions for the U.S. west coast even as sea life in the affected region again falls under threat. With global temperatures now hitting a range of 1.2 C or more above 1880s averages, there is risk that this event could match or even exceed the related harmful impacts seen during the 2013 to 2015 timeframe.
(Unusual high-amplitude Jet Stream ridging over the U.S. west coast like that predicted for Sunday in the GFS model run is associated with both extreme sea-surface temperatures in the northeastern Pacific [the hot blob] and sea-ice loss in the Arctic, both caused by global warming due to fossil-fuel burning. Note the numerous additional powerful ridge and trough formations running downstream of this unusual Jet Stream feature. Image source: Earth Nullschool.)

Climate Change Links Again Non-reported by Media

Despite an obvious relationship between global warming and extreme regional heating events like the hot blob, some prominent media sources continue to link the formation of the hot blob to natural variability without mention of climate change. To do so fails to tell the whole story. Without that 1.2 C warming of the Earth since the 1880s due to our rampant burning of fossil fuels, we would not be seeing so much heat piling up in the northeastern Pacific. As such, the PDO has been put into a kind of climate change hyperdrive. And that’s what’s creating conditions under which these big, dangerous ocean hot blobs continue to row.

Hat tip to DT Lange
Hat tip to Greg
Hat tip to Colorado Bob

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