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El
Nino Update: Monster Kelvin Wave Continues to Emerge and Intensify
2
April, 2014
(Kevin
Wave continues to strengthen and propagate across the Pacific Ocean.
Image source: NOAA’s
Climate Prediction Center.)
Record
global temperatures, extraordinarily severe storms for the US West
Coast and telegraphing on through the Central and Eastern US, a
disruption of the Asian Monsoon and various regional growing seasons,
record heat and drought in Northern Australia, severe drought and
fires in the Amazon, the same throughout Eurasia and into the
Siberian Arctic, another potential blow to Arctic sea ice. These and
further extreme impacts are what could unfold if the extraordinarily
powerful Kelvin Wave now racing toward the Pacific Ocean surface
continues to disgorge its heat.
The
most recent update from NOAA shows that
the monster Kelvin Wave we reported on last week
has continued to grow and intensify even as it shows no sign of
slowing its rather ominous emergence from waters off the west coast
of South America.
The
pool of 4-6+ degree Celsius above average temperatures continues to
widen and lengthen, now covering 85 degrees of longitude from 170
East to 105 West. Perhaps more disturbing is the fact that the zone
of extreme 6+ C temperature anomalies has both widened and extended,
covering about 50 degrees of longitude and swelling to a relative
depth of about 30-40 meters. This is an extraordinarily intense
temperature extreme that well exceeds those observed during the
ramp-up to the record 1997-98 El Nino event.
Meanwhile,
a smaller, but still disturbing, zone of 3-6+ C above average
temperatures has now developed just 100 feet below the surface along
a line near 100 degrees West Longitude. It is a very strong heat
pulse, the head of the Kelvin Wave that by late March had pushed its
nose up in the Eastern Equatorial Pacific.
(Deep,
hot Pacific Ocean water continues to shift east. Image source: NOAA’s
Climate Prediction Center.)
In
the above NOAA graph we can see the hot, deep pool in the Western
Pacific gradually flowing eastward, spreading out and shallowing as
it begins to dump its heat content back into the atmosphere. A return
of stored ocean heat that will, likely, spike global atmospheric
temperature values all while sparking off a series of very extreme
weather events.
Warm
Storms Continuing to Pull Heat Eastward and Upward
The
west-to-east progression and upwelling of Pacific Ocean heat is
currently facilitated by low pressure systems lining up along the
equator. The lows are fed by heat and evaporation bleeding off the
Pacific Ocean surface. This heat enhances the formation of
thunderstorms that join into larger, heat-driven cyclonic systems.
The countervailing circulations of these systems act to slow the
trade winds while allowing the hot pool to spread further and further
east.
It
is a pattern that tends to emerge at the beginning of most El Nino
events. A self-reinforcing cycle that draws energy from ocean surface
heat even as its intensity is enhanced more and more by heat transfer
from the depths.
(GFS model guidance through April 13 shows a persistent cyclone off New Guinea interrupting the trade winds — lower left — even as a long trough is predicted to form over the Eastern Pacific just north of the Equator — lower right. This pattern would tend to enhance the formation of El Nino conditions throughout the forecast period. Image source: NOAA)
It
is the kind of cycle in which the excess Ocean heat, amplified by
human-caused global warming, and long stored in the Pacific, as Dr.
Kevin Trenberth well observed,
may now be coming back to haunt us.
Conditions
of a Human-Altered ENSO Cycle Compared to the Most Recent Warming at
the End of the Last Ice Age
The
La Nina to El Nino cycle (ENSO) is part of a larger ocean and air
energy transfer pattern in which heat is periodically stored in the
vast equatorial waters of the Pacific before being returned again to
the atmosphere. In a normal climate state, this dance of heat energy
between the airs and the waters would result in simple periodic
variation appearing at the peak of either La Nina (atmospheric cool
extreme) or El Nino (atmospheric warm extreme). But because human
warming has now added a very strong and rapid heat forcing to this
natural cycle of variability, La Nina periods have displayed slower
rates of atmospheric warming (where they should have showed cooling)
and El Nino periods have often resulted in temperatures spiking to
new global records.
Natural
variation, in this case, rests on a curve that we are forcing to bend
inexorably upward.
Of
the .8 degrees Celsius worth of annual global warming experienced
since the 1880s, about .15 C, or nearly 20 percent of this warming,
occurred during the powerful 1997-98 El Nino event in which vast
amounts of stored ocean heat returned to the atmosphere. Since 1998,
the Pacific Ocean has undergone a long period of La Nina events in
which a large store of atmospheric heat was transferred to the global
ocean system. But despite this enormous heat transfer, global
temperatures continued to climb with new records achieved in 2005 and
2010 during relatively weak to moderate El Nino events.
For
the currently emerging El Nino, all indications point toward it being
as strong or stronger than the extraordinarily powerful 1997-98 El
Nino, perhaps readying to raise global temperatures by another .15 C
or more.
(April 1 Sea Surface Temperature Anomaly Map shows a band of 1-3 C above average temperatures covering the Equatorial Pacific. It’s a marked difference from the slightly cooler than average conditions that have dominated for much of the past year. Given the current Pacific Ocean weather context and the very strong Kelvin Wave lurking just beneath the surface, it appears to be the start of a powerful El Nino phase. Image source: NOAA/ESRL)
For
context, the difference between the 1880s and the last ice age was
about 4 degrees Celsius. A temperature change that took about 10,000
years to complete. The total current warming of .8 C is equal to
about 20% of the difference between the 19th Century and an ice age,
but on the side of hot. This warming occurred at extraordinary
velocity, over the course of little more than a century. An extreme
pace of warming now between 30 and 40 times faster than that at the
end of the last ice age. A pace of global heat accumulation that has
not been seen in at least 65 million years.
Under
business as usual fossil fuel emissions, even that very rapid pace of
warming could more than triple over the coming decades, producing a
warming equivalent to what occurred during the end of the last ice
age over the course of 10,000 years in less than 200. A disastrous
pace that will wreck untold harm on the world’s weather systems,
climates, ocean systems, geographies and ecologies should it emerge.
A
pace of warming that likely has no corollary even in the Permian Hot
House Extinction Event of 250 million years ago.
In
the current cycle of human warming, a strong El Nino can push that
measure by as much as 5% or more in just a single year. So we may
well see global average temperatures of 1 C higher than 1880s values
by the end of 2014-2015 should the current and very powerful El Nino
continue to emerge.
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