I am skeptical that this hypothesis will
actually hold up at all but it is making an important claim. It is that we will
have a sharp heat rebound when the trade winds do weaken. This heat rebound is supposed to reignite the
rising curve and generally fully recover all the apparent heat lost top date
from their models.
Of course we will see, but this is going
to have to be tested over the next ten years cat least.
In the meantime we are been reintroduced
to the polar vortex so prevalent when I was young. That also might continue on for a good decade
as well. I think that I will stay in
Vancouver.
There’s no “warming pause” — trade winds
are burying heat in the Pacific
Global average land temperatures
have not increased as quickly as many scientists had expected over the past 10
or 15 years, leading some climate skeptics to latch onto the bogus idea of a “global warming pause.” Last
year researchers reported that
much of the “missing heat” was not in fact missing but rather was being sucked upby
the oceans.
Now new research helps explain why excess heat is being absorbed into the sea: big-ass
winds.
A paper published
in the journal Nature Climate
Change suggests that the slowdown in surface warming and the
acceleration in ocean warming has been largely driven by a phase in a natural
ocean cycle called the Interdecadal Pacific Oscillation (IPO). That’s a
frightfully cumbersome name, but it’s easy to break down: It’s a swing (“oscillation”)
in Pacific Ocean weather that takes decades (“interdecadal”) to shift from one
phase to another. Instead of switching every few years, like El Niño and La
Niña, an IPO can last 20 to 30 years before flipping from one extreme to the
other.
“Global warming hasn’t stalled at all,” Matthew England, a
professor at the University of New South Wales in Australia and lead author of
the paper, told Grist. “There’s just more heat going into the oceans at the
moment.”
Since the turn of the century, the
IPO has been in a negative phase, which is marked by strong trade winds in the
Pacific. Researchers used models to simulate the effects of these winds on
ocean currents and discovered that the strong winds increase the amount of warm
water that sinks below the surface, while increasing the amount of cold water
that burbles up from ocean depths near the equator.
And that has helped bury extra heat at sea — for now.
From the paper:
Here we show that a pronounced strengthening in Pacific
trade winds over the past two decades … is sufficient to account for the
cooling of the tropical Pacific and a substantial slowdown in surface warming
through increased subsurface ocean heat uptake. …
The
net effect of these anomalous winds is a cooling in the 2012 global average
surface air temperature of 0.1–0.2◦C, which can account for much of the hiatus
in surface warming observed since 2001. This hiatus could persist for much
of the present decade if the trade wind trends continue, however rapid warming
is expected to resume once the anomalous wind trends abate.
This isn’t the first time in recent history that the oceans
have absorbed more than their normal share of extra heat. The paper describes a
similar surface-warming hiatus that occurred from the 1940s to the 1970s —
the last time the IPO was in this pronounced negative phase.
When the cycle inevitably reverses, the scientists warn that
some of the extra heat that’s currently swimming with the fishes will rise up
out of the ocean and come back to haunt us landlubbers.
“The IPO oscillates
roughly every 20 to 25 years, but the timing is quite unpredictable. What
we do know is that when we switch back to a positive IPO phase, the trade
winds will be much weaker,” England said. “Longer term, regardless of when
the winds relax, this temporary slowdown in surface warming will be overwhelmed
by greenhouse gas increases.”
Study links
stronger Pacific trade winds to pause in global warming
By Nick Lavars
February 10, 2014
Despite an overwhelming
consensus among climate scientists that warming trends over the past
century are most likely the result of human activities, some claim that a
plateau in global surface air temperatures since 2001 is evidence to the
contrary. However, a new study suggests the recent stabilization of air
temperatures is a result of abnormally strong east to west trade winds, causing
warmth to be stored temporarily beneath the western Pacific ocean.
The joint research, published in the journal Nature Climate Change and conducted by Australian and
US researchers, outlines an unprecedented intensification of trade winds,
easterly surface winds swirling about near the Earth's equator, which has
accelerated the circulation of the Pacific ocean.
This causes heat to be drawn from the atmosphere
into the waters below the ocean's surface and the colder water to rise to the
top, ultimately leading to cooler average global temperatures.
“Scientists have long suspected that extra ocean
heat uptake has slowed the rise of global average temperatures, but the
mechanism behind the hiatus remained unclear," said the study's lead
author, Professor Matthew England of the University of New South Wales in
Sydney, Australia.
According to the researchers, the strengthening of
the Pacific trade winds actually dates back to the 1990s. Climate models used
previously had not been able to account for the stalling of global surface
temperature, as they didn't incorporate the strengthening of these winds.
When England and his fellow researchers added data
from the heightened winds to their modeling, they found it accounted for a
cooling of 0.1 to 0.2° C (32.18 to 32.36° F) in the 2012 global average surface
air temperature, very closely mirroring the offset currently being observed.
"The winds lead to extra ocean heat uptake,
which stalled warming of the atmosphere," said Professor England.
"Accounting for this wind intensification in model projections produces a
hiatus in global warming that is in striking agreement with observations."
While the stronger winds offer respite from an
overall warming trend, Professor England warns that in the grand scheme of
things, the pause will be short lived and to little effect.
"This pumping of heat into the ocean is not
very deep, however, and once the winds abate, heat is returned rapidly to the
atmosphere," he said. "When the trade wind strength returns to normal
– as it inevitably will – our research suggests heat will quickly accumulate in
the atmosphere. So global temperatures look set to rise rapidly out of the
hiatus, returning to the levels projected within as little as a decade."
Source: University of New South Wales
About the Author
Nick was born outside of Melbourne, Australia, with
a general curiosity that has drawn him to some distant (and very cold) places.
Somewhere between enduring a winter in the Canadian Rockies and trekking
through Chilean Patagonia, he graduated from university and pursued a career in
journalism. He now writes for Gizmag, excited by tech and all forms of
innovation, Melbourne's bizarre weather and curried egg sandwiches.
All articles by
Nick Lavars
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