Tag Archives: arctic sea ice

Are we witnessing an Arctic Sea meltdown, right now?

The Arctic Sea freezes over. The Arctic Sea melts. This happens every year. The average date for the maximum extent of Arctic Sea ice, based on a period of 1981-2010, is March 12. The minimum extent is reached, on average, about September 15h.

Every year for the last several years, the minimum ice has been much lower than average in extent, and many years in a row have seen record minima. This is considered to be the result of global surface warming caused by human release of greenhouse gas pollution.

It is said that we can’t use the maximum ice cover to predict the minimum ice cover very accurately, because a lot of things can happen to affect the total ice cover during those many months of melting. However, the maximum ice amount for, say, 1979-1988 (the first ten years for which we have really good data on this) was high compared to the last ten year period, and correspondingly, the minimum extent was greater for that first ten year period than the most recent ten years, so there is a correlation. Still, the date of the maximum extent has tended to not move around much, and the same is true for the date of the minimum extent.

Bt maybe not this year. This year’s maximum Arctic Sea ice extent seems to have flatlined at a record low value, as shown in the graph above, from here. The current sea ice extent is that red line all by itself down near the bottom.

It may well be the case that the sea ice will start to re-freeze, and this line will go up again over the next two weeks or so, and max out near the historical average. The next week or so should be below freezing across much of the Arctic Sea, but there is a warm intrusion near Greenland and Europe, with above freezing air, expected to persist for that entire time. Overall, warm air and ice-breaking-up storms have invaded the Arctic repeatedly this winter. The sea ice extent may recover over the next several days, but I get the impression that most experts are quietly thinking it won’t.

This is not terribly surprising, given that the Earth’s surface temperatures are increasing, and sea ice is decreasing. This year, a El Ninño is adding fuel to the fire, as it were, and making these conditions even more extreme.

A concerning possible outcome is this: The Arctic Sea ice helps cool the planet by reflecting away sunlight. It is a reasonable assumption that during summers with much less ice, there is much less cooling. This can have impacts on the longer-lived fast ice* that is also melting in the arctic, and on nearby glaciers in greenland, and the planet overall. This is what is known as a “positive feedback” which is a somewhat misleading term, because this is not an especially “positive” event.

*CORRECTION: My friend and colleague Tenney Naumer, who watches both the weather and the Arctic very closely, contacted me to let me know that the “fast ice” is long gone. She told me, “In 2012, the ice in the channel between Ellesmere and Axel Heiberg Island (to the south of Ellesmere) melted out — that is the place where the ice had existed for more than 10,000 years. The Ward Hunt Ice Shelf broke off in 2002. The Ayles Ice Shelf broke off in 2005. In 2007, I watched (here) the ice break away from most of the Arctic side of the archipelago, and it has been all downhill since. It’s all gone now.”

The Arctic is Hot: New minimum sea ice cover for the date

… and not in a good way.

The Arctic has, of course, been warming in step with anthropogenic global warming, plus more. This phenomenon has probably increased disruption to global weather systems, especially in the Northern Hemisphere, over the last decade or so.

But something somewhat novel is happening this year, presumably as a result of global warming combined with a strong El Nino. Storms are bringing extra warm conditions to the Arctic. A few days ago, the North Pole was above freezing, and over the next few days we are expecting more warm conditions in the Arctic Circle. See this post by Eric Holthaus.

Figuring that interesting things might be happening in the Arctic, I had a look at the National Snow and Ice Data Center interactive graphic showing Arctic Sea ice cover now and over time. The graphic is at the top of the post. It turns out that Arctic Sea ice is at an historic low for this date, and in fact, looks to be flatlining, at least for now. I presume the ice will expand again shortly when the current influx of warm air to the region subsides, but it will be interesting to see if we end up with a new minimal maximum of sea ice.

Arctic Sea Ice Decline in 2015

The surface ice in the Arctic has been melting to historic low levels every year for the last several years. The graph above shows the first ten years in the National Snow & Ice Data Center records, meant to indicate what Arctic Sea Ice “normally” does as it melts off during the northern warm months. The thick black line is the average over 1981-2010, and grey shaded area shows two standard deviations above and below that line. The blue line tracking along the lower end of the 2SD shaded area is the ice extent this year. During the period when sea ice is at its maximum, this year’s ice was low. This does not reliably predict the ultimate September minimum, but it is interesting that the sea ice extent is following an extreme course.

I’m reluctant to say anything about what will happen this year. The melting rate could slow, storms that may play a role in diminishing sea surface ice in the Arctic may not play a big role. Or, the rate of melt could increase and all the various factors that determine a year’s minimum could drive the ice off the sea to the extent that we have a record low. It would be very hard to beat the 2012 minimum extent, as that was an extreme year. But, that extreme year, show on the figure below, was not as low at the present time as the current extent.

Screen Shot 2015-05-26 at 12.22.18 PM

The volume of sea ice is in some ways more important than the area it covers, because this reflects the overall Earth’s surface heat imbalance resulting from the human-induced greenhouse effect. Volume includes both new ice (formed over the previous winter) and old ice that does not melt at all in a given year. This old ice probably serves the role of keeping some of the new ice stable so it melts less, so there is a feedback. The more the volume reduces, the more the surface area may reduce, depending on various conditions.

Andy Lee Robinson has created, and regularly updated, an amazing graphic showing the change over time in Arctic sea ice volume.

Global warming’s effects are coming on faster than previously thought.

Arctic sea ice decline happened faster than expected. This has the effect of accelerating global warming because less of the Sun’s energy is reflected back into space by ice.

SeaIceDecline_591

Northern Hemisphere snow also sends some of that energy back into space. The amount of snow cover we have is also declining.

Difference from average annual snow extent since 1971, compared to the 1966-2010 average (dashed line). Snow extents have largely been below-average since the late1980s. Graph adapted from Figure 1.1 (h) in the 2012 BAMS State of the Climate report.
Difference from average annual snow extent since 1971, compared to the 1966-2010 average (dashed line). Snow extents have largely been below-average since the late1980s. Graph adapted from Figure 1.1 (h) in the 2012 BAMS State of the Climate report.

The warming of the Arctic region is also probably causing an increase in the amount of CO2 and Methane, previously frozen in permafrost or offshore, that is going into the atmosphere. For this and other reasons, Methane, along with other greenhouse gases, are increasing. I quickly add that stories you’ve heard of a civilization “methane bomb” in the Arctic are not supported by the best available science. But these additional greenhouse gases still count.

Global average abundances of the major, well-mixed, long-lived greenhouse gases - carbon dioxide, methane, nitrous oxide, CFC-12 and CFC-11 - from the NOAA global air sampling network are plotted since the beginning of 1979. These gases account for about 96% of the direct radiative forcing by long-lived greenhouse gases since 1750. The remaining 4% is contributed by an assortment of 15 minor halogenated gases including HCFC-22 and HFC-134a (see text). Methane data before 1983 are annual averages from D. Etheridge [Etheridge et al., 1998], adjusted to the NOAA calibration scale [Dlugokencky et al., 2005].
Global average abundances of the major, well-mixed, long-lived greenhouse gases – carbon dioxide, methane, nitrous oxide, CFC-12 and CFC-11 – from the NOAA global air sampling network are plotted since the beginning of 1979. These gases account for about 96% of the direct radiative forcing by long-lived greenhouse gases since 1750. The remaining 4% is contributed by an assortment of 15 minor halogenated gases including HCFC-22 and HFC-134a (see text). Methane data before 1983 are annual averages from D. Etheridge [Etheridge et al., 1998], adjusted to the NOAA calibration scale [Dlugokencky et al., 2005].

Now we are learning that glacial ice, in particular in Antarctica, is melting faster than expected.

That video is from a recent post by Peter Sinclair, who has more on glacial melting.

We knew a lot of the additional heat (from global warming) was going into the oceans, but now we have learned that a LOT of this heat is going into the ocean. This heat goes in and out, so what has been going in will likely be going out (into the atmosphere).

90% of the Earth's energy balance involves the ocean's heat, shown here. Note that there is no current pause, and that surface temperature estimates (see graph above) tend to underestimate the total amount of anthropogenic global warming because much of this heat, routinely, goes into the ocean. We can expect some of this heat to return to the atmosphere in coming years.
90% of the Earth’s energy balance involves the ocean’s heat, shown here. Note that there is no current pause, and that surface temperature estimates (see graph above) tend to underestimate the total amount of anthropogenic global warming because much of this heat, routinely, goes into the ocean. We can expect some of this heat to return to the atmosphere in coming years.

(See also this post by Joe Romm.)

This causes me to look at a graph like this

Figure SPM.5. Solid lines are multi-model global averages of surface warming (relative to 1980–1999) for the scenarios A2, A1B and B1, shown as continuations of the 20th century simulations. Shading denotes the ±1 standard deviation range of individual model annual averages. The orange line is for the experiment where concentrations were held constant at year 2000 values. The grey bars at right indicate the best estimate (solid line within each bar) and the likely range assessed for the six SRES marker scenarios. The assessment of the best estimate and likely ranges in the grey bars includes the AOGCMs in the left part of the figure, as well as results from a hierarchy of independent models and observational constraints. {Figures 10.4 and 10.29}
Figure SPM.5. Solid lines are multi-model global averages of surface warming (relative to 1980–1999) for the scenarios A2, A1B and B1, shown as continuations of the 20th century simulations. Shading denotes the ±1 standard deviation range of individual model annual averages. The orange line is for the experiment where concentrations were held constant at year 2000 values. The grey bars at right indicate the best estimate (solid line within each bar) and the likely range assessed for the six SRES marker scenarios. The assessment of the best estimate and likely ranges in the grey bars includes the AOGCMs in the left part of the figure, as well as results from a hierarchy of independent models and observational constraints. {Figures 10.4 and 10.29}

… and figure that warming over coming decades will be at, near, or even above, the range previously estimated.

Arctic Sea Ice Extent

Arctic Sea Ice extent continues to be a problem. This year, according to the National Snow and Ice Data Center, ARctic Sea ice reached its lowest extent this year on September 17th, which is about the sixth lowest extent on record, following a multi-year trend of decline. There is variation from year to year. This year’s minimum was almost exactly the same as last years. With the exception of 2001, minimum extent has been below the climatalogical average every year since 1998.

Dana Nuccitelli has a post on this with excellent discussion and some nice graphics, and he has also produced a new version of the animated “How ‘Skeptics’ View Arctic Sea Ice Decline” graphic, which I reproduce here:

ArcticEscalator500

How Melty Was The Arctic Sea This Year?

The Arctic Sea is covered with ice during the winter, and some of it melts off every summer. Over recent years the amount of melt has been increasing. This is the time of year we may want to look at Arctic Sea ice because by late September it has reached its annual minimum and is starting to reform.

Looking at JUST surface area, which is one indicator of how warm the Arctic has become with Global Warming, we can see (above) that this years march of melting has been extreme, hugging the two standard deviation limit for all of the data from 1979 to 2010 (almost the present).

Here you can see that 2014 is distinctly different, with much more surface area loss, than the first ten years of this data set, from here.
Screen Shot 2014-09-28 at 2.42.54 PM
And here you can see that 2014 is pretty much in the middle of the range for the “new normal” as represented by the most recent ten years:

Screen Shot 2014-09-28 at 2.43.33 PM

So, in answer to the question above, 2014 was a very melty year in the Arctic, though over very recent years there have been worse years. This year is about the sixth lowest minimum extent since 1979 or before.

Current Status of Arctic Sea Ice Extent

As it does every summer, the Arctic Sea ice is melting off. Over the last several years, the amount of sea ice that melts by the time it hits minimum in September has generally been increasing. So, how’s it doing now?

The graph above shows the 1981-2010 average plus or minus two standard deviations. Before going into more detail than that, you should look at the following graphic.
Arctic_Sea_Ice_First_v_Second_Ten_Years

The top chart shows the march of Arctic Sea ice melt for first ten years of the baseline data set only, and the bottom chart shows the last ten years of the same data set. This tells us that the two Standard Deviations for the period 1981-2010 hides an important fact. Since Arctic Sea ice is melting more and more every year, a proper baseline might be the first several years of this period, not the entire period.

Now refer to the graphic at the top of the post. This is the current year’s ice extent. Notice that it is tracking right along the lower edge of the 2 Standard Deviation zone. In other words, the present year is exhibiting what we have been seeing all along: An Arctic with much less ice.

Now look at the years that post date the baseline period, 2011 through the present, including the wildy extreme year of 2012 when a record melt was set.

Screen Shot 2014-07-22 at 12.04.56 PM

Here we see that collectively, the last three full years and the present partially documented year exist at the lower end of, or lower than, the 2 Standard Deviation zone. This suggests that the current trend is an extension of the previous couple of decades. More melting on average over time. One would hope this would level off, and maybe it will. But we certainly can not make that claim at this point.

Note that it is very hard to predict the ultimate minimum for a given year, even at this point. (Even so, I did it here way at the beginning of the season). We’ll have to wait and see.

Climate Trends in the Arctic as Observed from Space: It's melting. Fast.

Earth’s northern ice cap is heating up and melting down at an alarming, not previously predicted, rate. A paper just out in Wiley Interndisciplary Reviews: Climate Change, by Josefino Comiso and Dorothy Hall looks at recent historic transformations in the Arctic using satellite imagery, mainly from 1979 to the present. The decline of Arctic ice is so extreme that ice thought to have existed for over 1450 years is melting now. (None of the sea ice is really ancient, even the “old” ice recycles over geologically short time periods. But in the near future there will be virtually no “old” ice left in the region.)

According to author Josefino Cosimo, of NASA, “The Arctic region has been warming faster than anywhere else in the globe from 1981 to 2012. Such warming is manifested strongly in all components of the cryosphere in the Northern Hemisphere.”

The following list of chilling, or rather, not chilling, facts is paraphrased from the paper:

  • Warming in the region has been amplified … with the rate of warming observed to be ~0.60±0.07 o
    C per decade in the Arctic (>64 oN) compared to ~0.2 o C per decade globally during the last three decades.
  • sea ice extent has been declining at the rate of ~3.8% per decade,
  • while the perennial ice (represented by summer ice minimum) is declining at a much greater rate of ~11.5% per decade.
  • Spring snow cover [is] declining by –2.12 % per decade for the period 1967 to 2012.
  • The Greenland ice sheet has been losing mass at the rate of ~123 Gt per year (sea level
    equivalence of 0.34 mm per year) during the period from 1993 to 2010
  • for the period 2005 to 2010, a higher rate of [Greenland ice sheet] mass loss of ~228 Gt per year has been observed.
  • the average area of mountain glaciers has declined by as much as 10% per decade during the period from 1960 to 2000.
  • Increases in permafrost temperature have also been measured in many parts of the Northern
    Hemisphere while a thickening of the active layer that overlies permafrost and a thinning of
    seasonally-frozen ground has also been reported.

Here is the movie version of this review paper:

The review looks at clouds, albedo, and the Arctic Oscillation for insight as to how this is all happening. The Arctic Oscillation is one of those medium-term climate variations (like ENSO) which involves a large scale shift in the movement of air masses from one perennial pattern to another, often accompanied by effects having to do with sea surface temperatures or sea currents.

The Arctic Oscillation (AO), often referred to as Northern Annular Mode (NAM), has been regarded as among the most dominant modes in the [Northern Hemisphere], affecting atmospheric circulation and climate in the Arctic. Its direct impacts on the sea ice cover and wind circulation patterns have been evaluated using AO indices as presented for the entire year on a monthly basis in Figure 9a and for the winter period in Figure 9b. The plots show that the indices for both monthly and for the winter season are mainly positive since 1988 although there are years (e.g., 2010) when they become strongly negative. It has been previously reported that negative AO indices are associated with extensive ice cover while positive indices would correspond to a reduced sea ice cover. However, the indices have become nearly neutral in the recent decade while the sea ice cover continued to decline.

Screen Shot 2014-04-07 at 6.37.41 PM

The authors conclude that the link between the Arctic Oscillation and recent changes in the Arctic is unclear. This is hard to interpret without further research but it may be bad news: The recent changes seen in the Arctic and possibly effects not covered in this paper (but discussed frequently on this blog) on global weather don’t seem to be associated with “natural variation.”


The graphic at the top of the post is figure one from the paper, and has this caption: Location Map of the Arctic Region including average sea ice extent (yellow line), sea ice cover during record minimum in summer of 2012 (shades of white), continuous and discontinuous permafrost (shades of pink), glacier locations (gold dots) and snow cover (average location of 50% snow line in black and maximum snow line in green as inferred from MODIS data).

Josefino C. Comiso, Dorothy K. Hall, Climate trends in the Arctic as observed from space, WIREs Climate Change, DOI: 10.1002/wcc.277