Early in September each year I sit down to start reading the latest scientific research on the
state of play up in the Arctic, and every year I get reminded of what an immense and dynamic part
of the world it really is. I mean take the Arctic Ocean for example. You could fit all 50 American
states in there and still have plenty of room left over for a country the size of India! And
yet every winter temperatures drop low enough for its entire area to completely freeze over into an
ice sheet thick enough to effectively become a land mass. Then as the Northern Hemisphere comes
back around to face the Sun during the summer months the ocean absorbs enough solar radiation to
melt the excess winter ice away. It's a dance that Mother Nature has performed annually for more than
10,000 years since the end of the last ice age and it has huge influence on global ocean circulation
and Northern Hemisphere climate patterns. And then there's Greenland. An island the size of
the five largest Western European countries combined, 80 percent of which is covered with
an ancient ice sheet that's nearly two miles thick in its centre and a mile thick on average.
That equates to about 3 million cubic kilometres of water. Or put another way,
enough water to raise global sea levels by more than seven metres or about 24 feet. Now unless
you've been living under a rock for the past decade or so you will no doubt already be aware of
scientific research and modelling suggesting that global warming is reducing the amount of Arctic
sea ice that forms each year and melting some of the land-based ice from the Greenland ice sheet.
And you're probably aware that for all sorts of reasons that's not an ideal state of affairs.
But as researchers carry out more and more in-depth analysis of the region and ever more
sophisticated computer modelling software provides greater levels of accuracy, our
scientists are beginning to realize that previous studies have been seriously underestimating the
magnitude of the changes taking place. And in the summer of 2022 three separate peer-reviewed
papers were published that provide us with the unvarnished, and perhaps unwanted, truth.
Hello and welcome to Just Have a Think. A few years ago I heard a comedy parody of
a famous old Rudyard Kipling poem which went something like this...
"if you can keep your head while all those around you are losing theirs,
then you probably haven't understood the seriousness of the situation!" And that's a
sentiment that came to mind several times as I was reading through these new research papers.
So what's going on then? Well, let's start with one of the most visible symptoms before we look at
the causes. Around about this time in September, right at the end of a summer season of warming,
the extent of Arctic sea ice reaches its annual minimum. Back in 2012 there were some freak
weather conditions, including unusually warm North Atlantic Waters moving into the Arctic Ocean,
an area of freakishly warm water just south of Greenland, extra warm air coming in from
a record North American Heat Wave, and the transport of warm water vapor across
the surface of Greenland via what's known as an atmospheric river, delivered by the Atlantic. All
of that resulted in an uncharacteristically low September Arctic sea ice minimum. This year didn't
see such freakish conditions but nevertheless this September's minimum is still noticeably lower than
the 1981-2010 median. While it's nowhere near the 1 million square kilometres that is scientifically
defined as an ice-free Arctic, as some doom-mongers predicted it would be this year, it
does mark another step on an inexorable trajectory towards that eventuality. And it does look likely
that we will see ice-free summer Arctic conditions within the next decade, especially when we factor
in ice thickness. 10 years ago, when we had that historic low surface area event, there was still
a healthy amount of very thick multi-year ice stretching right out into the centre of the ocean.
That thick ice is now all but disappeared, and in many places the ice is now only centimetres thick.
One violent storm event could break up that wafer thin ice and cause it to melt away into the water.
One of the causes of this unfortunate phenomenon is exceptional warming over the Barents Sea area,
which this June 2022 paper delved into. Researchers from all these academic
institutions reanalysed warming in the Barents Sea over the past 40 years, based on newly
available observations and a quality controlled comprehensive data set taken from the sea's
northern archipelagos. Their result suggests a much stronger rate of atmospheric warming
compared to previous analysis. The team identified what they describe as a statistically significant
record high annual warming in the Barents Sea of up to 2.7 degrees Celsius per decade, with
a maximum in Autumn of up to 4 degrees Celsius per decade. This Arctic hotspot phenomenon isn't
just about warming air though. The researchers point out that the northern Barents Sea region
also hosts a more pronounced loss of winter sea ice than anywhere else in the Arctic, and since
the early 2000s the region has experienced a sharp increase in both temperature and salinity in the
entire water column caused by increased ocean heat transport entering the region from warming
Atlantic Waters in the West. Less fresh water in the ice means saltier water in the upper layers
of the ocean. That reduces ocean stratification and increases upward heat flux. The projection
is that if the rise in ocean temperature and salinity continues, the original cold and
stratified Arctic Shelf region may be transformed into an Atlantic dominated climate region with
a warmer and more well-mixed water column strongly preventing future sea ice formation.
That paper was followed on the 11th of August by this one, published by researchers at The
Finnish Meteorological Institute. Their objective was to apply the latest state-of-the-art climate
modelling techniques to four major observational data sets of Arctic temperatures dating back to
1979, which is when the modern era of satellite monitoring began. Previous climate simulations
from something called the Coupled Model Intercomparison Project, or CMIP, run by the World
Climate Research Program, suggested that Arctic warming over the last 43 years had been twice or
even three times higher than the global average. But by applying more sophisticated and holistic
modelling to the data, the Finnish researchers found that the old models were underestimating
the differential between Arctic warming and overall global warming by as much as 34 percent.
The new analysis showed that across the entire Arctic region warming since 1979 has on average
actually been about four times higher than the rest of the planet, and in a very large area of
the Eurasian Arctic local warming has been more like seven times higher than the global average.
And that extreme warming is inevitably impacting the vast ice sheet sitting on top of Greenland,
which brings us nicely to our third research paper published at the end of August 2022. This one was
a result of an academic collaboration between several universities and institutes led by the
Geological Survey of Denmark and Greenland. Once again the researchers identified shortcomings
in previous process-based models, including what they describe as imprecise atmospheric and oceanic
couplings. Correcting for those inaccuracies showed that, based on the climate over the
last 20 years or so, we're already locked into surface Mass loss from precipitation ice flow
discharge and melt water runoff that'll cause nearly 60,000 square kilometres of Greenland
ice sheet to slip away into the surrounding ocean in the coming decades, regardless of which climate
mitigation pathway our global leaders eventually agree on. That's about 3.3 percent of the total
mass of the ice sheet and it'll cause more than 27 centimetres, or about 12 inches of sea level rise.
And that's just based on average conditions over the last two decades. The researchers point out
that there can be a great deal of variability in Arctic conditions from one year to the next. 2018
for example was dominated by unusually cold waters coming in from the Atlantic and cold polar air
across Greenland's western side. That suppressed surface melt, and resulted in the lowest surface
mass loss recorded so far this century. The 2012 anomaly that I mentioned earlier though was at
the other end of the scale. As well as resulting in a record low September Arctic sea ice area,
it also caused increased and sustained surface melting and evaporation and melt water runoff
from the Greenland ice sheet. 2012 is more likely to be a portent of the future as well,
and if that year was taken as the analogue for a projected late 21st century sustained warmer
climate, then the researchers calculated that 10% of the ice sheet would disappear,
causing almost 80 centimetres of global sea level rise. That'd impact hundreds of millions of people
in coastal areas around the world who'd lose their livelihoods as sea water encroached on
agricultural land and possibly even their lives as extreme storm surges devastated entire regions.
And if all that lot wasn't enough to cheer you up, we got a bonus fourth research paper just
last week from the Stockholm Resiliency Centre, outlining all the tipping points that could be
triggered if we go beyond 1.5 degrees Celsius of average global surface temperature warming
compared to pre-industrial times, which by the way we're only 0.3 degrees away from right now.
Greenland ice sheet collapse sits right at the top of the list, kicking in with conviction as
temperatures rise by less than 2 degrees Celsius. The paper's projections also show that abrupt sea
ice loss that we just looked at in the Barents Sea and the collapse of an important circulatory
system in the North Atlantic. Two degrees also causes the die off of low latitude coral reefs
and it accelerates the collapse of the West Antarctic ice sheet. If we stray towards
four degrees of warming the researchers say we're looking at serious consequences in the Amazon and
the loss of mountain glaciers all over the world. Go beyond four degrees and the Arctic Sea is not
only ice free in the summertime but ice free all year round. The permafrost in the vast expanses
of boreal forests thaws out allowing microbes to digest the organic matter and release huge
quantities of methane into the atmosphere. The famous AMOC ocean circulation system grinds to
a halt, and the immense land-based East Antarctic ice sheet starts to give way. There's enough water
locked up in there to raise sea levels by 52 metres or 170 feet, which is not something I
think any of us would want to inflict on our grandchildren and their descendants.
These tipping points are like a massive planetary scale game of dominoes. The first few dominoes to
fall represent fairly abstract concepts that few of us directly feel the effects of. But
as those dominoes create more tipping points further along the line the consequences become
increasingly tangible for the majority of the human population until they eventually become
existentially threatening to all of us. That's why the scientific community is imploring us to
lose our apparent fixation with 1.5 degrees Celsius or 2 degrees Celsius of warming,
which are the upper and lower targets set by the Paris agreement in 2015. Those numbers are
pretty much irrelevant now because even at 1.2 degrees of warming we've already set in motion
the first few tipping points. What we've got, say our scientists, is an emergency. And what
we need is for our global leaders to implement immediate emergency measures to deal with it.
And if you want to dig into the detail of the papers I've referenced in this
video then as always I'll leave links in the description section below to each one of them.
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