It’s been a while since I wrote, in On Climate for a Change, that I
would next write about sea ice. Well
that didn’t quite happen, because I got distracted. It’s not just one rabbit hole with climate
denialism, it’s a whole web of rabbit holes.
Anyway, it’s time to make good on my promise (or
threat, if you prefer). To make things
easy, I am going to refer to my interlocutor on the topic of climate change and
climate denialism as “JP”. JP has been
sliding into denialism and, I suspect, is now pretty much most of the way
there. I find it easier to think of JP
as being a soft denialist rather than grapple with the incongruity of believing,
simultaneously, that anthropocentric climate change is real and that that “Tony
Heller is a wizard with data who (sometimes) makes a lot of sense, it’s just
that occasionally he’s bit hyperbolic” or “Joanne Nova/Judith Curry makes a
compelling argument”.
My friend, JP, started all of this when writing:
If you
were to ask me 2 years ago what my key understandings were about climate
change, I would have said the following:
- Sea ice is rapidly shrinking (summer arctic sea ice to be gone by 2015)
- Sea levels are rising and accelerating
- Polar bear populations are under stress (have increased in the last 20 years)
- The levels of glacial retreat around the world are unprecedented (similar retreats have been seen in the last century)
- 97% of scientists agree that global warming is real and an urgent problem
- Any scientist who is skeptical about the claims made about climate change is a "denier" and is funded by oil/resource companies
- We are seeing an increase in extreme weather events (they are actually getting less common)
- Climate models are accurate in their predictions
Every
one of those things is either totally false, or a largely exaggerated claim.
My response was to look into the substance of each
point made and email back with what I found.
That effort became the basis of the article below which is focused, as
you may have guessed, on sea ice, edited to suit the blog format better and
enhanced with later data that I came across only recently. I will post about some the other issues
separately in more depth later, while some might just be touched on in a series
of articles that I intend to put together on the nature of climate
denialism. Please note the caveat that I posted earlier
was, in part, an edited version of the prelude to what follows.
---
JP’s Claim: The statement “sea ice is rapidly
shrinking (summer arctic sea ice to be gone by 2015)”
is either totally false or largely exaggerated
The term “rapidly” was not defined, although within
context of no sea ice by 2015, we could make a guess. The original statement was hyperbolic, so
should be taken with some salt (harvested from the sea perhaps) and I would not
be willing to defend it unconditionally.
I will be defending the more modest claim that “sea ice is
shrinking”.
---
In December 2007, BBC reported that Dr Wieslaw
Maslowski had projected that the Arctic could be ice-free in summer in 5-6
years with a headline that read “Arctic summers ice-free ‘by 2013’”.
Maslowski is not alone in predicting ice-free conditions, but from what I can
see the numbers are small:
Dr Peter Wadhams, who is called a
“climate alarmist” by The Guardian (generally considered
hard-left on climate change), is aggressive on his ice-free predictions and has
been spectacularly wrong – predicting ice-free conditions in 2016 back in 2012.
Overland and Wang predicted (in
2013) ice-free conditions by (or before) roughly 2020, but that was only when
using one of three methods of projections.
The IPCC AR5 presented a number of scenarios, one of which
predicted that ice free conditions might occur around 2050.
The NCA agrees with the IPCC, although
they say it is expected that ice free summers should occur by the middle of the
century.
Overland and Wang had, from a
different projection methodology, a prediction of 2040. In a more recent paper, Overland is more
cautious, suggesting ice-free conditions within a few decades. (I could make a
joke about not seeing Wang much recently, but I’ll leave the Wang jokes to Phil Wang.)
Prof. James Anderson provides the
most recent aggressive prediction that I could find. He used atmospheric chemistry to assess and
model climate change (and was involved in the CFC/ozone hole palaver). He
said in 2018 that "The chance that there will be any permanent ice left in
the Arctic after 2022 is essentially zero" but this doesn’t seem to be
linked to any specific paper. I doubt
that this comment will turn out to be a visionary (and accurate) prediction
given that the reduction in “sea extents” over the past forty years. It’s bad, but the timing seems out for no ice
by 2022 (NSIDC):
Note that the sea ice question is particularly vexed when one considers Antarctica. The term “sea ice extent” refers to the area of ocean that is covered by at least 15% ice whereas “sea ice area” refers to the area of ice and this will always be less than the sea ice extent. But this is just sea ice. In Antarctica (and Greenland), there is also a need to consider land ice.
An example of issues with sea ice measurements and the
associated claims is provided by Anthony Watts of the Watts Up With That? climate
denialist blog. Watts claimed that
Arctic sea ice is “not cooperating with doomsday predictions” and provided this
chart:
It is true that in 2018, sea ice extent in the Arctic
was only two standard deviations below the 1981-2010 average at its
lowest extent. However, this
isn’t telling the whole story. See the graph below for 2012, 2018,
2019, 1981-2020 average and ±2σ (for the Arctic):
Watts extracted the boxed section, so he took it out
of context – thus ignoring period Jan-mid Jun when the sea ice extent was less
than in 2012. Of course, the northern
summer/autumn is when the entirety of the ice pack would disappear according to
the most extreme “doomsday” predictions so that gives Watts a valid reason to pick
that period. However, the trend is
downwards:
It’s true that some scientists (but note not all
scientists) predicted the “doomsday scenario” too early, based on insufficient
evidence, but the apparent trend is nevertheless toward there being little to
no ice in September by 2050-2060 – unless there are mechanisms that I don’t understand
(which is entirely possible and was core to Maslowski’s argument) causing this
to happen much earlier, or much later.
What the evidence doesn’t show (without cherry picking) is that there’s
absolutely nothing to worry about.
There is an equivalent set of charts for the
Antarctic:
The Southern Hemisphere is cooler than the Northern
Hemisphere (which is counterintuitive given that the country that you normally
associate with the Southern Hemisphere, Australia, is on a rather warm
continent). There is a bit more sea ice
associated with Antarctica (and Antarctica is normally colder than the Arctic),
but there is also a lot more land ice. The whole continent is covered in an average of more than 2000m of ice. If that all melted it would be … bad.
Interestingly, with regard to sea ice, we don’t see
the same sort of pattern as we do with the Arctic over the past 40 years:
There’s basically no pattern but, if pushed, I'd say it looks
like there’s possibly a slight tendency towards more ice (but that is screwed
up by the more recent years being slightly below average. What’s going on there?
It’s basically the fact that Antarctica is losing ice overall
(land and sea ice combined) with land ice diminishing at a rate that
counteracts (and in fact contributes to) the increase in sea ice. In total, the Antarctic Ice Sheets lost about 35-45Gt a year from 1979 to
1990, about 150-175Gt a year from 1999 to 2009 and 225-275Gt a year from 2009
to 2017.
---
So, the claim made by JP was that sea ice is not
rapidly shrinking and won’t be gone by 2015.
Well, I might have to admit defeat if I were contesting that claim
although it’s unclear what the definition of “rapidly” is in this context. The summer sea ice was not gone by 2015,
certainly not by 2013 and doesn’t look like it will be gone by 2022 – and there
is still plenty of winter sea ice.
Predictions that sea ice would disappear that quickly have turned out to
have been exaggerated. I’m not sure that
we could say that a projection into the future, even if found later to have
been wrong, was “totally false” especially when the projections were provided
in a particular context with caveats which were later discarded by media
outlets and activists. There’s a big
difference between “could be” and “will be”.
To say that the claims, as made by the people who are accused of making
them were wrong, we would have to show that it would have been impossible,
given in the conditions prevailing at the time the claim was made, for the
claim to have come to fruition.
However, the claim that I was defending was a more
modest one, that “sea ice is shrinking”.
The evidence to hand shows that not only is the extent of sea ice
trending down, but so too is the mass of land ice. Therefore, the claim is neither totally false
nor largely exaggerated.
---
It should be noted that while melting of the Arctic
sea ice would be a problem for seals and polar bears that make their home there
(and a boon for nations that want a shortcut around Eurasia), it would
not have an impact on sea levels. (Nor
would the total disappearance of sea ice from Antarctica.) Sea ice already displaces the amount of water
that would be released by its melting.
Land ice however is an issue, so going on about sea ice melting is a bit
of a distraction. Disappearance of all
sea ice would certainly be a signal of things going bad for the planet but it
would, in itself, be unlikely to be a cause of further problems – other than to
seals and polar bears (and possibly the whales that tend to hang around under
the ice and, in the Antarctic, penguins).
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