A
Major Surge in Atmospheric Warming Is Probably Coming in the Next
Five Years
Forget
the so-called ‘pause’ in global warming—new research says we
might be in for an era of deeply accelerated heating.
23
March, 2015
While
the rate of atmospheric warming in recent years has, indeed, slowed
due to various natural weather cycles—hence the skeptics’ droning
on about “pauses”—global warming, as a whole, has not stopped.
Far from it. It’s actually sped up, dramatically, as excess heat
has absorbed into the oceans. We’ve only begun to realize the
extent of this phenomenon in recent years, after scientists developed
new technologies capable of measuring ocean temperatures with a depth
and precision that was previously lacking.
In
2011, a paper in Geophysical Research Letters tallied up the total
warming data from land, air, ice, and the oceans. In 2012, the lead
author of that study, oceanographer John Church, updated his
research. What Church found was shocking: in recent decades, climate
change has been adding on average around 125 trillion Joules of heat
energy to the oceans per second.
How
to convey this extraordinary fact? His team came up with an analogy:
it was roughly the same amount of energy that would be released by
the detonation of two atomic bombs the size dropped on Hiroshima. In
other words, these scientists found that anthropogenic climate is
warming the oceans at a rate equivalent to around two Hiroshima bombs
per second. But as new data came in, the situation has looked worse:
over the last 17 years, the rate of warming has doubled to about four
bombs per second. In 2013, the rate of warming tripled to become
equivalent to 12 Hiroshima bombs every second.
So
not only is warming intensifying, it is also accelerating. By burning
fossil fuels, humans are effectively detonating 378 million atomic
bombs in the oceans each year—this, along with the ocean’s
over-absorption of carbon dioxide, has fuelled ocean acidification,
and now threatens the entire marine food chain as well as animals who
feed on marine species. Like, er, many humans.
According
to a new paper from a crack team of climate scientists, a key reason
that the oceans are absorbing all this heat in recent decades so well
(thus masking the extent of global warming by allowing atmospheric
average temperatures to heat more slowly), is due to the Pacific
Decadal Oscillation (PDO), an El Nino-like weather pattern that can
last anywhere between 15-30 years.
In
its previous positive phase, which ran from around 1977 to 1998, the
PDO meant the oceans would absorb less heat, thus operating as an
accelerator on atmospheric temperatures. Since 1998, the PDO has been
in a largely negative phase, during which the oceans absorb more heat
from the atmosphere.
Such
decadal ocean cycles have broken down recently, and become more
sporadic. The last, mostly negative phase, was punctuated by a brief
positive phase that lasted 3 years between 2002 and 2005. The authors
of the new study, Penn State climatologist Michael Mann, University
of Minnesota geologist Byron Steinman, and Penn State meteorologist
Sonya Miller, point out that the PDO, as well as the Atlantic
Multidecadal Oscillation (AMO), have thus played a major role in
temporarily dampening atmospheric warming.
"In
other words, the ‘slowdown’ is fleeting and will likely soon
disappear."
So
what has happened? During this period, Mann and his team show, there
has been increased “heat burial” in the Pacific ocean, that is, a
greater absorption of all that heat equivalent to hundreds of
millions of Hiroshimas. For some, this has created the false
impression, solely from looking at global average surface air
temperatures, of a ‘pause’ in warming. But as Mann said, the
combination of the AMO and PDO “likely offset anthropogenic warming
over the past decade.”
Therefore,
the “pause” doesn’t really exist, and instead is an artifact of
the limitations of our different measuring instruments.
“The
‘false pause’ is explained in part by cooling in the Pacific
ocean over the past one-to-two decades,” Mann told me, “but that
is likely to reverse soon: in other words, the ‘slowdown’ is
fleeting and will likely soon disappear.”
The
disappearance of the ‘slowdown’ will, in tangible terms, mean
that the oceans will absorb less atmospheric heat. While all the
accumulated ocean heat “is certainly not going to pop back out,”
NASA’s chief climate scientist Dr. Gavin Schmidt told me, it is
likely to mean that less atmospheric heat will end up being absorbed.
“Ocean cycles can modulate the uptake of anthropogenic heat, as
some have speculated for the last decade or so, but… net flux is
still going to be going into the ocean.”
According
to Mann and his team, at some point, this will manifest as an
acceleration in the rise of global average surface air temperatures.
In their Science study, they observe: “Given the pattern of past
historical variation, this trend will likely reverse with internal
variability, instead adding to anthropogenic warming in the coming
decades.”
So
at some point in the near future, the PDO will switch from its
current negative phase back to positive, reducing the capacity of the
oceans to accumulate heat from the atmosphere. That positive phase of
the PDO will therefore see a rapid rise in global surface air
temperatures, as the oceans' capacity to absorb all those Hiroshima
bomb equivalents declines—and leaves it to accumulate in our skies.
In other words, after years of slower-than-expected warming, we may
suddenly feel the heat.
So
when will that happen? No one knows for sure, but at the end of last
year, signs emerged that the phase shift to a positive PDO could be
happening right now.
In
the five months before November 2014, measures of surface temperature
differences in the Pacific shifted to positive, according to the
National Oceanic and Atmospheric Administration. This is the longest
such positive shift detected in about 12 years. Although too soon to
determine for sure whether this is, indeed, the beginning of the
PDO’s switch to a new positive phase, this interpretation is
consistent with current temperature variations, which during a
positive PDO phase should be relatively warm in the tropical Pacific
and relatively cool in regions north of about 20 degrees latitude.
In
January 2015, further signs emerged that the PDO is right now in
transition to a new warm phase. “Global warming is about the get a
boost,” ventured meteorologist Eric Holthaus. Recent data including
California’s intensifying drought and sightings of tropical fish
off the Alaskan coast “are further evidence of unusual ocean
warming,” suggesting that a PDO transition “may already be
underway a new warm phase.”
While
it’s still not clear whether the PDO is really shifting into a new
phase just yet, when it does, it won’t be good. Scientists from the
UK Met Office’s Hadley Center led by Dr. Chris Roberts of the
Oceans and Cryosphere Group estimate in a new paper in Nature that
there is an 85 percent chance the faux ‘pause’ will end in the
next five years, followed by a burst of warming likely to consist of
a decade or so of warm ocean oscillations.
Roberts
and his team found that a “slow down” period is usually (60
percent of the time) followed by rapid warming at twice the
background rate for at least five years, and potentially longer. And
mostly, this warming would be concentrated in the Arctic, a region
where temperatures are already higher than the global average, and
which is widely recognized to be a barometer of the health of the
global climate due to how Arctic changes dramatically alter trends
elsewhere. Recent extreme weather events around the world have been
attributed to the melting Arctic ice sheets and the impact on ocean
circulations and jet streams.
What
this means, if the UK Met Office is right, is that we probably have
five years (likely less) before we witness a supercharged surge of
rapid global warming that could last a decade, further destabilizing
the climate system in deeply unpredictable ways.
A
Major Surge in Atmospheric Warming Is Probably Coming in the Next
Five Years
3
March, 2015
In 2011, a paper in Geophysical Research Letters tallied up the total warming data from land, air, ice, and the oceans. In 2012, the lead author of that study, oceanographer John Church, updated his research. What Church found was shocking: in recent decades, climate change has been adding on average around 125 trillion Joules of heat energy to the oceans per second.
How to convey this extraordinary fact? His team came up with an analogy: it was roughly the same amount of energy that would be released by the detonation of two atomic bombs the size dropped on Hiroshima. In other words, these scientists found that anthropogenic climate is warming the oceans at a rate equivalent to around two Hiroshima bombs per second. But as new data came in, the situation has looked worse: over the last 17 years, the rate of warming has doubled to about four bombs per second. In 2013, the rate of warming tripled to become equivalent to 12 Hiroshima bombs every second.
So not only is warming intensifying, it is also accelerating. By burning fossil fuels, humans are effectively detonating 378 million atomic bombs in the oceans each year--this, along with the ocean's over-absorption of carbon dioxide, has fuelled ocean acidification, and now threatens the entire marine food chain as well as animals who feed on marine species. Like, er, many humans.
According to a new paper from a crack team of climate scientists, a key reason that the oceans are absorbing all this heat in recent decades so well (thus masking the extent of global warming by allowing atmospheric average temperatures to heat more slowly), is due to the Pacific Decadal Oscillation (PDO), an El Nino-like weather pattern that can last anywhere between 15-30 years.
In its previous positive phase, which ran from around 1977 to 1998, the PDO meant the oceans would absorb less heat, thus operating as an accelerator on atmospheric temperatures. Since 1998, the PDO has been in a largely negative phase, during which the oceans absorb more heat from the atmosphere.
Snip
So at some point in the near future, the PDO will switch from its current negative phase back to positive, reducing the capacity of the oceans to accumulate heat from the atmosphere. That positive phase of the PDO will therefore see a rapid rise in global surface air temperatures, as the oceans' capacity to absorb all those Hiroshima bomb equivalents declines--and leaves it to accumulate in our skies. In other words, after years of slower-than-expected warming, we may suddenly feel the heat.
So when will that happen? No one knows for sure, but at the end of last year, signs emerged that the phase shift to a positive PDO could be happening right now.
In the five months before November 2014, measures of surface temperature differences in the Pacific shifted to positive, according to the National Oceanic and Atmospheric Administration. This is the longest such positive shift detected in about 12 years. Although too soon to determine for sure whether this is, indeed, the beginning of the PDO's switch to a new positive phase, this interpretation is consistent with current temperature variations, which during a positive PDO phase should be relatively warm in the tropical Pacific and relatively cool in regions north of about 20 degrees latitude.
In January 2015, further signs emerged that the PDO is right now in transition to a new warm phase. "Global warming is about the get a boost," ventured meteorologist Eric Holthaus. Recent data including California's intensifying drought and sightings of tropical fish off the Alaskan coast "are further evidence of unusual ocean warming," suggesting that a PDO transition "may already be underway a new warm phase."
While it's still not clear whether the PDO is really shifting into a new phase just yet, when it does, it won't be good. Scientists from the UK Met Office's Hadley Center led by Dr. Chris Roberts of the Oceans and Cryosphere Group estimate in a new paper in Nature that there is an 85 percent chance the faux 'pause' will end in the next five years, followed by a burst of warming likely to consist of a decade or so of warm ocean oscillations.
So
what does all this mean? According to this report, "What this
means, if the UK Met Office is right, is that we probably have five
years (likely less) before we witness a supercharged surge of rapid
global warming that could last a decade, further destabilizing the
climate system in deeply unpredictable ways."
Our representatives in congress are having snow ball fights, perhaps in a few years the world will demand that all fossil fuels stay in the ground. Hopefully, we will have time to figure out how to survive this looming catastrophe..
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