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. That's it for this week though. Thanks as
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