In reading postings in one of my favorite blogs recently
(Neven’s superlative Arctic Sea Ice blog), it
occurred to me that I hadn’t tried to summarize in my mind the two major surprises
that scientists recognized in climate change last year. What follows is my take on these surprises:
- Arctic methane is venting much faster than expected; and
- The weather effects of global warming are stronger than expected.
What are the implications?
Let’s take them one at a time.
Arctic Sea Ice and Methane
It still amazes me that most people did not see the
likelihood that Arctic sea ice was going to take a nosedive to near zero in the
2013-2016 period, because I only had to apply some basic math when I first took
a look in 2009: exponential and normal
curves.
Until recently, there was only one serious attempt to assess
the volume of Arctic sea ice: Maslowski’s
PIOMAS model. As I understand it, people
tended to dismiss the model because Maslowski said: this is the way I model Arctic sea ice
dynamics, and therefore the sea ice volume should change over time in this and
this way; and because he asserted without proof in his model that Arctic Ocean
water temperature changes had a major role in increased melting over time. However, when I saw that this model was
constantly reality-tested by on-the-site sampling, even though each sample was
of a small part of the overall Arctic Ocean, I realized that the long-term
trends there were likely to be true. And
what Maslowski’s model showed, at any time of the year, was an exponentially
decreasing Arctic sea ice volume.
By the way, recent Cryosat observations have definitively
shown that, if anything, Maslowski’s model has underestimated the rate of
volume decrease.
So why, I asked myself, do I not see corresponding decreases
in Arctic sea ice area and extent? As I
looked at the dynamics of Arctic sea ice, I realized that that could only
happen if there was a uniform distribution of Arctic sea ice thickness from,
say, zero to twice the average thickness (at any time of year). But what was really going on was that a
certain percentage of the sea ice survived between years to become second year
ice, third, and so on; but cue to currents, the average age of Arctic sea ice back
in 1980 was five years – sooner or later, ice frozen at one end of the Arctic
would reach the other end and head south into warmer waters, there to
inevitably unfreeze. Instead, thickness
(with a little adjustment for the age of the ice) had much more of a normal
distribution around the average. And that, in turn, meant that accelerated
volume losses at, say, minimum would only show up in area and extent when we
reached the fat part of the curve – which, it is now apparent, occurred in
2012.
By the way, the same logic also says that volume and the
rest will not go to zero somewhere around 2014 – 2015; we will have reached the
other thin end of the distribution, and the exponential decrease in volume will
flatten out, exponentially. That’s why I
fully expect to see around 1-5% of the ice remaining at minimum until sometime
around 2016-2020.
So, as I’ve said, I expected that Arctic sea ice would begin
to obviously disappear around now, and I expected the climate change
implications of this – including the fact that Russian-Arctic-Continental-shelf
methane “clathrates” would begin to release their methane. What I (and apparently others) did not expect
was the scale of that release. A Russian
sampling of methane bubbling to the surface found huge pockets of the stuff –
hundreds of times more than research had suggested might be the case.
Before I go on to discuss this, let me cycle back to the (expected)
implications of Arctic sea ice melt.
Today’s models simply do not include melt to near zero at minimum in the
2013-16 time period, and a likely follow-on melt to near zero at all times of
the year between 2035 and 2045. This in turn, will not directly lead to more
carbon emissions. What it will do is
decrease Arctic Ocean albedo (from off-white-reflection to dark-blue-absorption
of heat from the sun during the spring-summer-fall), and therefore warm up the
Arctic Ocean portion of global and ocean temperature. This already is 15-20 degrees Fahrenheit above
normal during the summer; we are talking another 25-35 degrees by 2045, taking
it to 20-25 degrees during the winter.
The increased water and air temperature should therefore (a)
accelerate methane clathrate melt, including that of the deeper waters nearer
the North Pole, and (b) both cool and warm winter temperatures of more
temperate zones – with the “warm” predominating over time. How can (b) be? Well, warmer Arctic air has more energy, and therefore
pushes south against the “jet stream” more strongly, creating weather in which
unusually cold Arctic air reaches further south periodically. However, that same Arctic air is steadily
warming over time, to the point where by 2050 it should be as warm as or warmer
than southern winter air was in, say, 1980.
Implications of the Methane Surprise
Part of the problem with assessing methane’s implications is
that most if not all scientists have not factored in 2015-2045 Arctic sea ice
melt’s implications for temperatures just a bit further south. Because methane clathrate melt should be
understood as part of a “double whammy” for methane – Arctic methane melt at
the same time as permafrost melt.
Since (up to a point) methane has a very short half-life in
the atmosphere (say, 8-10 years), you need a much greater rate of methane
release into the atmosphere than carbon (all right, methane includes carbon
too, but methane has a much greater effect on global warming per ppm than
carbon dioxide) to achieve a comparable warming effect over time. And yet,
studies of 55 million years ago, when the rate of warming was much less,
indicates that methane had a major role in causing what Joe Romm at www.climateprogress.com calls “Hell
and High Water”, with 90% of species wiped out.
Scientists have made a persuasive case for the idea that,
even if methane clathrates are starting to melt and permafrost at the same time
(i.e., even if we factor in Arctic sea ice melt), methane emissions will not
reach a “danger point” where their effects in the atmosphere will rival that of
carbon emissions any time soon – and therefore will avoid the main danger time
of carbon emissions, before the lack of fossil-fuel reserves begins to decrease
those emissions on its own). The problem is that the Russian observations
indicate that those reassurances are based on assumptions about the rate of
methane clathrate “bubble” occurrence that far underestimate their rate and/or
amount.
So what, then, are the likely implications of this methane
surprise? As far as I can see, there are
no “likely” implications, because the range of possible methane “bubble” rates,
and therefore emission rates, over the next 40 years is so wide. Nor is
it clear to me, given that these emissions are occurring in such a localized
northern area, just how wide an effect on global warming there will be. However, my best guess is that over the next
40 years there will be a significant, localized effect: Methane emissions will increase Russian and
lower-Arctic-sea heat retention over what it would have been by perhaps 25%,
with a corresponding increase in Arctic average temperature and Russian
permafrost methane/carbon release. This,
in turn, may add perhaps ½ degree Celsius to global warming over the next 40
years – and, of course, will add a comparable amount over the 50 years
following, at least – always remembering that a major fraction of methane
released turns into carbon dioxide, and hangs around in the atmosphere for a
hundred years or so on average. In other
words, the major effect of the surprise may be a more long-term one: arrival of a ½ - 1 degree Celsius additional
increase in “thousand-year” global warming now rather than later, when it would
have less practical effect.
The Weather Effect Surprise and Implications
Taking my cue from James Hansen and Joe Romm, I had
guesstimated in 2009 that we in the US would first see constant, undeniable
reminders that global warming is real in the 2020-2025 timeframe. These reminders would include not only “hundred-year”
hurricane-type wind speeds and scorching summers that created Dust-Bowl
conditions in many areas, but also an overall burden of disasters that reached
0.1% of GDP even for a country like the US.
I believe it was Heidi Cullen that imagined NYC missing a massive
hurricane in 2017 and getting one in 2041, by which time the city was prepared
and the sewers did not back up and overflow, causing hundreds of thousands of
deaths from disease.
But, as Joe Romm noted in his blog, the things that should
have been expected in 2020-2025 seem to be happening in 2011-2012, ranging from
devastating Australian rainstorms to stupendous Russian wildfires to Hurricane
Sandy and its 13-foot storm surge (still short of the 20-odd-foot storm surge
that might cause the sewer outlets to be closed and the sewers to back up, but
enough to flood the subways and make downtown Manhattan, Queens, and Staten
Island disaster areas). It appears that
the monetary effects of disasters globally, according to insurers like Munich
Re, are 10 times what they were a decade ago, and there is no reason why they
should not continue to double or triple by 10 years from now – meaning that the
timetable for effects on global GDP should perhaps be moved up by 3-5 years.
The surprise is not that global warming is happening faster
than predicted – globally, 2012 was actually about average for the last decade,
which in turn means that it was one of the “dips” in our steady, accelerating
global temperature ascent. The surprise is that the effects on weather were
larger than expected. What I suspect is
that forecasts simply assumed that certain catastrophic events would happen
more frequently than expected, but could not predict that these catastrophes
would spread to areas where they had not before (devastating tornadoes in western
Massachusetts), areas that were less adapted to a new set of weather patterns.
We are reaching the point where we have not only extremes of existing weather
patterns, but also new climates that produce new weather patterns.
And so, I also suspect that the effects of the “weather is
changing faster than we expect” surprise are, like the methane surprise, bad
but unpredictable. I anticipate that the
Nino/Nina cycle and North Atlantic Oscillation patterns that have driven
weather around here since time immemorial (i.e., the last 5,000 years) are
changing, but will manifest first in longer versions of the extremes of this
cycle – and that’s a total guess. Certainly,
an extended Nino would mean even greater Dust Bowl conditions and summer heat
over a great extent of the US for longer than ever before, even leaving out the
effects of the ongoing global temperature warming. Initial predictions show the US except the
Northeast and Pennsylvania in catastrophic drought conditions in 2050 – is it
possible it could happen before then?
Boy, I hope not. But, as a clueless Presidential candidate
noted in 2008, hope is not a plan.
Conclusions
Overall, oddly enough, the implications of these surprises
for me are not great. I concluded in
2009 that we desperately needed to cut carbon emissions in absolute terms by
40% 2010-2020, and another 40% 2020-2030.
Since then, with extremely minor exceptions, all major countries in the
world have utterly wasted their time in that regard. In fact, my definition of functional insanity
is to see oil companies and countries seeing Arctic sea ice melt as an
opportunity for increased drilling of fossil-fuel carbon pollutants, and the
United States seeing a Keystone XL pipeline that solidifies tar-sand drilling
that sharply increases the likelihood of the end of all life on Earth as an
opportunity worth considering, much less actually being relatively close to
implementing it.
So, to my eyes, the horrible effects of the two 2012
surprises simply speed up what’s coming and increase its bad effects in
relatively minor ways, and that will be worth it if people wake up now and
start doing something globally effective.
Except that there’s little sign as yet that people and their leaders are
even beginning to understand the urgency of an adequate scale of action.
I wonder what new surprises 2013 will bring? I could really use some good news.
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