Update on the 2017 Arctic Melt Season

I made a posting on March 22 where I made a way-too-early forecast on the Arctic sea ice melt season. In that forecast I calculated the sea ice minimum extent for this year would approach 3 million square kilometers, which would easily be the minimum extent ever measured. The season is well advanced, so I thought this would be a good time to update that forecast and see how things are panning out.

To start with, this is the Charctic graph from NSIDC for July 4:

Source: NSIDC

As you can see, the current extent is competing with the lowest extents ever recorded for this date.The actual extent NSIDC reports for July 15 this year is 7.857 million square kilometers, which is more than 1.7 million square kilometers below the 1981-2010 average extent of 9.564 million square kilometers for that date.

This is the sea extent as shown by the Climate Change Institute (click on the image to view a larger version):

Source: CCI

The light blue line shows the 1979-2000 average sea ice extent. The ice-covered area is designated with a white-to-gray coloration. The more gray it is, the more broken-up the ice is with solid ice shown as pure white. As we can see, none, or very little, of the sea ice is shown as pure white. It is almost all some shade of gray. It also easy to see that areas that were historically ice-bound this time of year are now ice free. Take a look at Hudson Bay. It is almost entirely ice free (and has been for several weeks now), but historically would still have extensive amounts of ice. The Northwest Passage across northern Canada and Alaska is almost open, which would be a historically early occurrence for this rare event.

Here is the map of the sea ice extent from the Danish Polar Portal:

Source: Polar Portal

Again, the shade of the ice indicates the amount of coverage with sold ice being pure white. We can see, once again, that there is very little area that is pure ice. Most of the Arctic sea ice is broken up to various degrees. This is important because breaking the ice up into smaller pieces increases the surface area and makes it easier for it to melt. Broken ice will melt faster than solid ice.

But, extent isn't the only factor we need to consider. We also need to look at the ice thickness. This is the sea ice thickness as provided by the Polar Institute with the scale shown on the bottom of the image:

Source: Polar Portal

The cooler the color, the thinner the ice. This shows the ice is not only breaking up, but is also very thin.

Comparing these graphs makes me believe we will see all of the dark blue, purple and violet areas in the above graph melt by the end of the melt season in September. The red and white areas will survive. At this time of year, I think the green areas will, too, but in a much thinner state. Which leaves the light blue areas and I think about half of those areas will melt. On the map above, I estimate the minimum extent will still cover about half of the circular area around the pole and fill approximately two of the 10-degree blocks south of that circle. Using the same math I used in my March 22 posting, this comes out to be about 2 million square kilometers for the northernmost circle and about 325,000 square kilometers for each of the squares. This comes out to a total of approximately 2.7 million square kilometers.

A major factor is the weather. The Arctic weather started the year much warmer than average, but it has been mild-to-cold this summer and not as conducive to melting sea ice as in previous years. Here is a graph from NSIDC showing the cumulative freezing days starting on July 1 of the previous year and continuing to July 1 of the current year. The shaded areas show the percentile ranges (as listed) over the period 1981 through 2010:

Source: NSIDC

We can see the 2017 season has been significantly warmer than any other year and has been far outside of the percentile ranges. But, we can also see the difference from the base-line has decreased in recent weeks.


The weather factor is discussed at length in this PIOMASS posting. In particular, take a look at the graph of the Daily Average Arctic Sea Ice Thickness From PIOMASS located at the bottom of the posting, right before the comments section. This graph shows the thickness is not only historically low, but it has been all year. But, one of the things documented in this post is that the difference between 2017 and 2012 (the year of record low extent) is closing, where 2017 was much lower than 2012 to begin with. Using this input, let's postulate that the ice melt will not occur quite as severely as I speculated above. Based on that input from PIOMAS and NSIDC, let's bump the minimum extent estimate up to an even 3.0 million square kilometers.

This estimate is consistent with my March estimate and would be dangerously lower than the previous lowest minimum extent of 3.4 million square kilometers that occurred in 2012.

Sea Ice Status

It's becoming repetitive to say the situation for sea ice is bad. The situation is bad, getting worse and has been doing so for a long time. So, to say the situation concerning the sea ice extent this winter has been bad really isn't news. It's now routine. Maybe that's the news. We have reached the point where good news about sea ice will be the exception and bad news will be the norm.

We now have to wonder if we have reached a turning point with regard to sea ice. What I mean is that we can no longer simply conclude the sea extent is decreasing, we have to wonder if it hasn't collapsed. Take a look at these graphics from NASA, one from 1984 and the other from 2016.

Source: NASA

Source: NASA

In particular, compare the two graphs showing the ice extent by age. The bar on the far right shows the 'old' ice, which is typically more than 4 meters thick. You can easily see for yourself how much of the old ice has disappeared. This is important because thinner ice obviously melts faster than thick. With reduced extent, the amount of ice is not only reduced, but the thick ice has really taken a big hit. Thinner ice means it is more likely we will see even more decline in the ice in coming years.

But, there is another problem. The amount of open water increases the chances of the ice being broken up by waves. Waves hitting the ice will tend to break it up and broken ice will melt faster than sold ice due to the increased surface area (crushed ice in your drink melts more quickly than the same amount of ice as cubes). Waves are getting worse due to the increased open sea, so more ice is being broken up.

Fetch is the term describing how long a wave has to build. The longer the fetch, the more likely the wave will be larger. That's why ocean waves are larger than waves on a lake and waves on a lake are larger than waves on a pond. The larger the fetch, the larger the wave. As the ice extent gets smaller, the fetch in the Arctic Ocean gets bigger, meaning the typical wave, especially in a storm, will be bigger. Here is a nice article discussing this issue.

So, ice extent is getting smaller, ice thickness is getting thinner, waves are getting larger. Can anything else go wrong? Yes, as a matter of fact. Take a look at the air and sea water temperature anomalies.

Source: Climate Change Institute

Source: Climate Change Institute

The air temperature is more than 20 degrees F warmer than normal and the sea water temperature is about 4 degrees F warmer than normal. It become much harder to make ice when the air and water are warmer.

Take another look here:

Arctic Temperature 2016 - Danish Meteorological Institute

Arctic Temperature 2017 - Danish Meteorological Institute

But, the real question is, why is it so warm? Because there is more open water, which absorbs sunlight and gets warmer during the sunlit months instead of reflecting it. So, as the ice extent recedes, the very thing that caused it to recede in the first place gets worse, causing an even greater amount of recession in future years, which allows an even greater amount of sunlight absorption. At some point, the amount of open water will cause a complete breakdown of the sea ice.

Are we at the breakdown point, yet? I think so. We'll see ice in the winter simply because the Arctic has long nights in the winter months and it will still get cold. That's due to the tilt of the Earth's axis and climate change will not affect that. But, those nights, while still deadly cold, won't be as cold as they were before, meaning we won't see as much sea ice. Here is today's ice extent. The light blue line shows the long-term average for comparison purposes.

Source: Climate Change Institute

The sea ice extent has been trending much more than two-standard deviations below the long-term average and is setting new records for the least amount of extent ever measured for this time of year. The below graph is from the National Snow and Ice Data Center and shows the ice extent as a function of day of the year. The solid line towards the top is the long term average. The dotted line is the ice extent for 2012, the year with the record low minimum extent. The purple line is for 2006, the previous low year for this time of year. The unfinished, light blue line is for 2017. The shaded areas show one- and two-standard deviations from the long-term average.

Source: NSIDC

Based on this data, I'm going to forecast that the sea ice maximum extent will occur in the first week of March and will be about 14.2 million square kilometers. That would make it the lowest maximum extent ever recorded. I'll also go out on a limb here and give my forecast that 2017 will set the record for the lowest minimum extent in September.

In case you were wondering, things are not much better in Antarctica.

Source: NSIDC

But, we aren't done. Take a look at this graph of Greenland's mass balance.

Source: Polar Portal

The graph on the bottom shows the mass of Greenland has been going up substantially this winter. You would think this is good news, but it isn't. The reason is that the mass isn't suppose to be increasing that much. The annual increase in mass comes from snow accumulation during the winter. But, it should be only a limited amount. The Greenland Ice Sheet is about 7000 feet high and the air is bitterly cold and bone dry up there. So, where is all of this added mass coming from? The unfortunate answer is that it's coming from the open water of the Arctic Ocean. That same water that is above average in temperature. It's evaporating and ending up on the ice sheet as snow. While evaporation will help cool the water, the fact that there is all this snow means it was too warm to begin with. This means the climate dynamics in the Arctic are changing and that can't be good news. And, this added mass is not likely to stay. The trend for Greenland is for decreasing mass.

Source: Polar Portal

The general consensus is that the Arctic will routinely experience ice-free summers some time around 2050. That may be so, but I'm willing to predict we will see the first ice-free Arctic summer within the next ten years. It won't stick, but the first one is coming much sooner than we want to believe.

But, even with the mountain of scientific data available to anyone with an Internet connection, the science deniers are still claiming the ice extent is not going down. Truly amazing. By the way, don't read that article unless you want to know how much disinformation can be crammed into one article. But, if you scroll down a few paragraphs, the author makes the claim the state of the sea ice is just fine. Clearly, science and reality don't have any affect on him. Oh, and someone should tell him 2-meter ice isn't old ice, it's new. Old ice is at least 4 meters thick. You can reach any conclusion you want when you don't care about the facts.