Posts Tagged ‘Arctic Sea Ice’

When will the North Pole become the North Pool?

December 16, 2016


It is a sad fact, but it is likely that within my lifetime it will become possible to sail to the North Pole. I am 56.

Tragically it is also true that there is absolutely nothing that you or I can do about it.

In fact, even in the unlikely event that humanity en masse decided it wanted to prevent this liquefaction, there would be literally nothing we could do to stop it.

The carbon dioxide we have already put in the atmosphere will warm the Earth’s surface for a few decades yet even if we stopped all emissions right now.


The particular line of causation between carbon dioxide emissions and warming of the arctic is long, and difficult to pin down.

Similarly it is difficult to determine if a bull in a china shop broke a particular vase, or whether it was a shop helper trying to escape.

Nonetheless, in both cases the ultimate cause is undeniable.

What does the figure show?

The animation at the head of the page, stolen from NASA’s Earth Observatory, is particularly striking and clear.

The animation shows data from 1979 to this past November 2016 showing the extent of sea ice versus the month of year.

Initially the data is stable: each year is the same. But since the year 2000, we have seen reductions in the amount of sea ice which remains frozen over the summer.

In 2012, an additional one million square kilometres – four times the area of England Scotland and Wales combined – melted.

The summer of 2016 showed the second largest melt ever.

The animation highlights the fact that the Arctic has been so warm this autumn, that Sea Ice is forming at an unprecedentedly slow rate.

The Arctic Sea Ice extent for November 2016 is about one million square kilometres less than what we might expect it to be at this time of year.

My Concern 

Downloading the data from the US National Snow and Ice Data Centre, I produced my own graph of exactly the same data used in the animation.

The graph below lacks the drama of the animated version at the head of the article. But it shows some things more clearly.


This static graph shows that the minimum ice extent used to be stable at around 7 ± 1 million square kilometres. The minimum value in 2012 was around half that.

The animated graph at the head of the article highlights the fact that the autumn freeze (dotted blue circle) is slower than usual – something which is not clear in the static graph.

My concern is that if this winter’s freeze is ‘weak’, then the ice formed will be thin, and then next summer’s melt is likely to be especially strong.

And that raises a big question at the very heart of our culture.

When the North Pole becomes the North Pool, where will Santa live?


Arctic Sea Ice Update: Spring 2016

March 6, 2016
Graph showing the extent of Arctic Sea Ice in millions of square kilometres. This  has been measured by satellites on almost every day since 1979. It looks as though the Sea Ice Maximum this year will be the lowest ever recorded.

Graph showing the extent of Arctic Sea Ice in millions of square kilometres. This has been measured by satellites on almost every day since 1979. It looks as though the Sea Ice Maximum this year will be the lowest ever recorded. Data courtesy of the US National Snow and Ice Data Centre. Click for a larger version of the graph.

While I have been venturing South and East, the Arctic regions have been a enjoying a mild end to their long winter.

One way to quantify this is to use satellite imagery to measure the extent (in millions of square kilometres) of the area of sea which contains at least 15% of Sea Ice. This figure is called Sea Ice Extent.

When the sea and air are cold, Sea Ice grows quickly and extends over a large area. So this relatively simple measurement provides a ‘proxy’ measure for the severity of the Arctic Winter.

Fortunately we have a continuous record since 1979 and the graph at the head of the page shows this years data in context.

Although the freeze is not quite (it usually ends around the Equinox on March 21st), it looks like the extent of Arctic Sea is the lowest it has been at this time of year – at least since 1979.

This is consistent with the long-term trend which has seen the Maximum Extent of Sea Ice shrink by approximately 40,000 square kilometres per year on average.

This is only half the long-term trend in the Minimum Extent of Sea Ice which occurs every September. This has been shrinking by approximately 83,000 square kilometres per year on average.

Using just a linear extrapolation, we would expect the entire Arctic ocean to be free of Sea Ice in September in just 60 years – by 2076. However there many reasons to expect this to happen much faster.

Personally, I expect see the Arctic ‘ice-free’ in summer in my lifetime, which I am anticipating will end in 2040 at the age of 80.

It is worth noting that the record low extent of the winter freeze is not necessarily an indicator that the summer melt will also reach a record low extent. The US National Snow and Ice Data Centre have an excellent discussion of these issues and many more here.


P.S. Whew: All that and still I managed to avoid the use of the phrase minumum maximum!

Lord Franklin should have waited

September 23, 2014

The first I knew of Lord Franklin was when I heard an old song sung by John Renbourn which told his sad story.

In 1845 Franklin sailed to ‘find a passage around the pole ‘ – the so called ‘North-West passage’ to the North of Canada, emerging through the Bering Straits into the Pacific.

But Franklin, along with his two well-stocked ships and 129 men disappeared, and no trace of them was found despite searches in subsequent years.

Recent research has established that his ships became frozen in ice and with his sailors he over-wintered on the ice. And then they slowly perished from cold and hunger.

And now, after all these yearsParks Canada have discovered one of his ships underwater in a state of near perfect preservation.

And they have released a haunting underwater video.

This part of the arctic is still inhospitable in winter, but the winter sea ice is not as thick or extensive as it was in Franklin’s day.

And in summer, it is now possible to take a cruise through the ‘legendary’ North West Passage.

And the sea ice is diminishing in extent and volume year by year. This year the summer melt of Arctic Sea (Charts here) ice is nearly over  and the trend is continuing.

Graph showing the extent of Arctic Sea Ice at its minimum area each September. The datum for 2014 is estimated as being the value on 18th September 2014.

Graph showing the extent of Arctic Sea Ice at its minimum area each September. The datum for 2014 is estimated as being the value on 18th September 2014.

So Franklin should have waited. And if his successor were to sail in  2045 rather than 1845, then they would likely find the North West passage to be more mercenary than ‘legendary’.




Arctic Sea Ice 2012

September 10, 2012
Sea Ice Summer 2012

Daily satellite records of the extent of Arctic Sea Ice since 1980. The regular pattern of of melting and re-freezing appears to have been significantly disturbed in recent years. Click for a larger version. Data from NSIDC – see text for links.

I have returned from my holidays and the children are back at school. So I guess summer is over and it’s time for my annual check on how the Arctic sea ice is doing. … What?

The summer minimum of Arctic sea-ice extent will probably be reached in the next couple of weeks but already the previous minimum sea-ice extent has been undercut by more than a half-a-million square kilometres. Currently there are only around 3.5 million square kilometres of sea ice. The previous minimum value in 2007 was 4.2 million square kilometres. In the 1980’s – when I was twenty-something and unconcerned about Climate Change – a more typical figure would have been 7 million square kilometres of sea ice.

The graph at the head of the page shows the data which is collated from spreadsheets available here, here (old data) and here (new data). A multitude of graphics are available at the US Snow and Ice Data Center.

The BBC has reported this story pretty thoroughly and even The Register is shocked! But I am almost lost for words.

  • First we need to remind ourselves that nobody – and I mean nobody – knows what is going to happen next. However it looks like the people modelling the volume of arctic sea ice have their models just about right. Even while the sea-ice area was relatively stable, the ice thickness was probably declining. Once a minimum thickness is reached, the coherent ice sheet is broken apart by weather. The reflectivity of the surface then changes and much more solar radiation is absorbed. It is interesting to note that in contrast with the recent changes in summer sea-ice, the sea-ice winter maximum appears be only declining rather slowly.
  • If the volumetric modelling is correct, then as I mentioned previously, over the next few years – and I mean years and  not decades – summer ice in the Arctic will reduce in extent dramatically. It is quite plausible that even by 2020 we could have a few days each year in which there is no coherent ice sheet in the Arctic.
  • Once the sea-ice melts in summer then  each year the number of days that the ice melts will increase and summer ocean surface temperatures will begin to rise above zero. It is not clear that we will ever reach a situation in which sea ice will not form in winter – but it is possible. Remember that summer in the Arctic is more intense than anywhere else on Earth. It is a shocking fact that during each day of the Arctic summer, more solar energy falls on each square metre of sea or ground in the Arctic than ever falls on a square metre of ground in the tropics or deserts.

In my opinion this data speaks more eloquently than either myself, or reams of scientific papers discussing global temperature. This data speaks eloquently and it is saying very clearly – “something dramatic is happening in the Arctic: be concerned.”

When the ice melts…

September 8, 2011
The annual melting of arctic sea reaches its maximum extent in September. This year the melting has been roughly similar to 2007, the greatest extent of melting since humans evolved as a separate species. Click for a larger Image. Data from NSIDC

The annual melting of arctic sea reaches its maximum extent in September. This year the melting has been roughly similar to 2007, the greatest extent of melting since humans evolved as a separate species. Click for a larger Image. Data from NSIDC

As we near the end of summer in the northern hemisphere, the annual melting of the free-floating sea ice is reaching its maximum extent. Soon the temperatures will fall, the ice will re-form, and another winter freeze will commence. The annual melting has been the subject of satellite observation for more than 30 years and there is no doubt that the extent of the summer melting is increasing.

The data from the US National Snow and Ice Data Centre indicate that this year will probably see the greatest extent of summer melting ever seen since humans evolved as a separate species around one million years ago. Compared to 1979, this summer has witnessed the melting of an additional  2 million square kilometres of sea ice. Just to repeat that: two MILLION square kilometres! This is an area of roughly one thousand miles by one thousand miles. It is colossal.

As a specialist in temperature measurement, I am familiar with the use of ‘temperature fixed-points’ for calibrating thermometers. Even when heated, a mixture of ice and water does not increase in temperature, but instead maintains a stable temperature close to 0 ºC until all the ice has melted. In this sense, the arctic ocean in summer forms a gigantic, planetary-scale  fixed point. But when all the ice has melted, heating the liquid causes a temperature rise. And climatalogically, should the summer ever see the complete melting of arctic sea ice – in perhaps as little as 50 to 100 years according to current trends – we can expect the temperature of the region to begin to rise: no longer will an ice-water mixture stabilise the regional temperature.

The gob-smacking magnitude of ‘ice events’  – even on a smaller scale – is evident in this BBC story about the area left by the Peterman Glacier when it broke off from Greenland last year. It is still a major hazard to shipping around Newfoundland with a web page tracking it constantly and this video gives some idea of the scale of just one of the iceberg fragments.

And is all this due to anthropogenic global warming? Well I don’t know, and neither does anyone else. But it is a distinct possibility that we have played a part.

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