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Ireland's political and cultural magazine
April 2016 6 7
F
ormer NASA chief climatologist, Jim
Hansen has a prejudicial knack of
being right a lot more often than he's
wrong. And when it comes to project-
ing the future path of climate change,
he has an equally unfortunate habit of being
well ahead of the scientific posse.
Back in the sweltering summer of 1988
Hansen testified to the US Congress on climate
change, a phenomenon that was, until his elec-
trifying presentation, seen as something of a
scientific curio, an issue that distant future gen-
erations would, eventually, have to
confront. Hansen confirmed that not only was
it real, it was already happening. Calculations
Hansen published in the late 1980s of likely
future climate change track what has actually
occurred with uncanny accuracy.
Fast forward to 2015, a year in which global
temperatures were smashed by record margins
to make it, by some distance, the hottest ever
recorded. And temperatures recorded in the
first two months of 2016 have been described
by climate scientists as “off the charts”.
The February 2016 global temperature anom-
aly is +1.35C above average. It took from the
beginning of the industrial revolution until
October 2015 to record a +1C global tempera-
ture rise. To add another 0.35C within less than
six months has left the scientific community
running out of superlatives.
And now Hansen is back. He and 19 col-
leagues have just published a blockbuster
paper in the journal Atmospheric Chemistry &
Physics. While the IPCC’s assessment reports
represent the conservative mainstream view of
climate science, Hansen and his colleagues can
be said to be at the bleeding edge.
What their research has concluded is pro-
foundly disturbing, throwing into question
almost everything we think we know about how
climate change is likely to play out in the 21st
century. While the IPCC plumped for a likely
maximum sea level increase this century of
around 1 metre, Hansen argues this may be a
hopeless underestimate.
“The models that were run for the IPCC report
did not include ice melt, and we also conclude
that most models, ours included, have exces-
sive small-scale mixing, and that tends to limit
the effect of this freshwater lens on the ocean
surface from melting of Greenland and Antarc-
tica”, Hansen told a press conference marking
the launch of his paper last month.
How Hansen sees this playing out in the real
world reads like apocalyptic science fic-
tion. Instead of a slow, incremental increase in
sea levels, he believes we are looking at multi-
metre sea-level rises in the coming decades,
not centuries.
Nor will this be a gentle process: he predicts
devastating superstorms quite unlike anything
since the last Ice Age, and the near-shutdown
of major ocean currents such as the Atlantic
Meridional Overturning Circulation (AMOC), or
the Gulf stream, that vast current of warm tropi-
cal water that keeps northwest Europe, including
Ireland, from not being frozen solid for several
months a year.
If this is beginning to sound familiar, you're
probably thinking of the movie ‘The Day After
Tomorrow’, where abrupt climate change trig-
gered a massive freeze in the northern
hemisphere. That, of course, is purely specula-
tive; there is already far too much excess heat
in the system for the return of widespread Ice
Age conditions anytime in the next hundred
millennia.
What is truly alarming, according to Hansen,
is that as the heat differential between the
equator and the northern hemisphere
increases, this is likely to fuel powerful mid-lat-
itude storms, on a scale not endured in
thousands of years.
Such storms could be powerful enough
indeed to pick up massive boulders weighting
thousands of tonnes and toss them hundreds
of metres inland. We have clear evidence that
this has happened before – and he believes it
can happen again.
With severe storms battering the world's
coastal regions, compounded by rapid sea-
level rise, the nightmare scenario of most of the
world's great cities being lost to coastal inun-
dation moves from being some distant spectre
far beyond the year 2100 and bang smack
into the middle of this century.
Cork, Dublin, Galway, Belfast, Limerick,
Wexford... the list goes on, and that's just on
this tiny island.
Apart from the unimaginable human misery
and forced migration of millions, the economic
impact is almost incalculable Most of our criti-
cal infrastructure, including all the world's
great ports and trading hubs would be lost.
Not everyone agrees. Professor Peter Thorne
of NUIM was among those who reviewed Hans-
en’s paper, and while not ruling out worst-case
scenarios, believes publicising them may be
counterproductive.
“Does this actually confuse, does it cause
despair, does it help or hinder? I don’t know
whether communicating something like this
actually elicits a response that says: let’s do
something”, he cautions.
John Gibbons blogs at thinkorswim.ie and is
on twitter @think_or_swim
Pray he’s wrong
Hansen believeswe are looking
atmulti-metresea-level risesin the
coming decades, not centuries.
by John Gibbons
It took from the
beginning of the
industrial revolution
until 2015 to record a
+1C global temperature
rise. To add another
0.35C within 6 months is
devastating
