Guest essay by Robert A. Cook, PE
Last week, in my previous article, several critics noted an apparent decline in their Arctic Sea Ice Extents when it dipped back down from a high point over the March 7-8-9 period.
Was this an “early” Arctic Sea Ice Extent maximum? Was today’s Arctic Sea Ice in a truly irreversible decline towards a future catastrophic sea ice level, or was this (yet another!) example of the beginning of the long-postulated Arctic Sea Ice Decline?
Well, the honest answer is –as it always is with “climate” questions and challenges – “We don’t know. Yet. “
First, look at a few plots from the WUWT Sea Ice Page that illustrate this concern.
NSIDC Arctic Sea Ice Extents dipped, then remained “flat” for several days.
DMI (Denmark) Arctic Sea Ice Extents: Dipped down, then bounced back up – but only a little bit.
NORSEX/NANSEN Arctic Sea Ice Extents: Also dipped down the first week in March, but bounced up a little bit.
So, were these fears correct? Had the 2015 Arctic Sea Ice reached its yearly maximum “early” … Visibly lower than ANY previous year in the satellite record?
But, let’s look at a long term Arctic sea ice record by a different lab (Cryosphere, University of Illinois). See the Sea Ice Pages, lowest links, for the full northern and southern Cryosphere links to down load any desired data files from 1979 to 2015. http://wattsupwiththat.com/reference-pages/sea-ice-page/
Then, to look at just the days around the sea ice maximum, let’s isolate and plot only those days whose long-term average (1980-2010) are greater than 13.0 million km^2. That curve is plotted below.
So. First, notice that the Arctic Sea Ice “averages” tell a better tale. The maximum occurs over a 10-15 day span, with small dips and bounces even during the maximum peak. So, are bounces unusual?
No. They are so frequent that even a 40 year “average” cannot create a smooth, even curve when plotted! But the “maximum” curve is so broad, so flat across its top that we will not be able to see the 2015’s “Maximum Arctic Sea Ice” Area until well after it has passed us by and has begun its decline.
What is interesting – and may be important, or may be totally a distraction is the “timing” of that maximum point. Look again across the plots above for Sea Ice Extents. Notice how the Arctic Sea Ice extents have been “peaking” later the past 8 to 15 years? Even the Cryosphere average for 1980 – 2010 peaks significantly earlier than it does the past 10 years. So, each day after the spring equinox that the peak sea ice delays causes more and more solar energy to be reflected (lost form the earth’s heat balance back into space) that it was back in earlier “baseline” years.
(Notice also that September’s minimum point is also occurring a little bit later (between 15-20 September) than the longer-term average minimum point of 1979-2000.)
Of course, we have no satellite data for Arctic (or Antarctic) sea ice extents before 1979. What happened before? We don’t know. Observations and tales and the (very few) reports back then just do not cover enough area to know. But I recommend tracking BOTH the Arctic maximum AND minimum points against their longer “average” peaks to see what can be pulled out from the plots. It may be interesting.
It may be totally inconsequential.
In short, the small bounces that were seen last week, that were of so great a concern among some WUWT readers, are typical of the Arctic and Antarctic sea ice around the maximum and minimum points. We are so close to last season’s averages and areas that most of 2015 data points overlap the 2014 point for that day. Last year’s late peak may happen again.
Or it may not. As we write this on March 13, the last survey area was March 11, and Arctic sea ice was back higher at a little over 13.0 Mkm^2. Will it go higher yet up towards 13.14 Mkm^2 over the next 10- 15 days? Probably. It has gone higher before. And will get higher again in the future.
Losing the memory of low extent
Now – A second, probably more important observation. Will this week’s Arctic Sea Ice “maximum” matter in the future? Will the Arctic Sea Ice declines affect next year’s Arctic Sea Ice area and extents – leading irreversibly to a “decline” or “Arctic Death Spiral” – to capitalize the seriousness of the charge?
You have heard or read the charge if not once, one or two hundred times: Loss of Arctic sea ice means more solar energy is absorbed into the darker Arctic Ocean waters now exposed to the sun. More heat absorbed means the Arctic Ocean heats up more, which melts more Arctic sea ice, which causes yet more solar radiation to be absorbed, which causes yet more ocean water to heat up and melt more sea ice. The next year, the Arctic sea ice begins from a lower extents, and so has less mass to melt during the 24-hour summer days and so there is less thick (second and third-year ) sea ice – which allows even more Arctic sea ice to melt even faster.
The Royal Society of London reviewed that oft-repeated scenario September, 2014. And rejected it.
In September of 2014, the Royal Society of London held a workshop focused on the reduction in Arctic sea ice extent. One outcome of this meeting was a greater understanding of the overall trajectory of September ice extent. In a nutshell, it appears that very large departures from the overall downward trend in September extent are unlikely to persist into the following September. If a given September has very low ice extent, strong winter heat loss results in strong ice growth, so that the “memory” of the low ice September ice extent is lost. If a given September has a high ice extent, winter heat loss is more limited, meaning less ice growth. Consequently, while there can be large departures from year to year from the downward linear trend in ice extent (e.g., September 2012 compared to 2014), the natural tendency is for the large departure to dampen out, so that, overall, ice extent stays on the long-term downward trajectory that will eventually lead to seasonally ice free conditions as the Arctic continues to warm in response to rising atmospheric concentrations of Greenhouse gases.
Now, the NSIDC cleverly inserted a computer graphic and paragraph by Julienne Stroeve distorting this conclusion – and their paragraph should be included as well.
Figure 4. This graph shows future projections of September sea ice extent under various future greenhouse gas emission levels. Limiting the warming in 2100 to about 1 to 2 degrees Celsius (2 to 4 degrees Fahrenheit) under the RCP2.6 emission scenario would help to stabilize ice conditions at levels seen today. The RCP8.5 emission scenario (warming by about 4 degrees Celsius 0r 7 degrees Fahrenheit by the end of this century) would result in a seasonally ice-free Arctic by the end of this century. Credit: Julienne Stroeve
So, the NSIDC carefully used model predictions/projections to assure us (the readers) that Arctic sea ice is actually going to disappear in the near future, and all of the gloomy CAGW-assumptions requiring Catastrophic Artificial Constraints will be necessary after all.
But. What did the Royal Society’s actually conclude in September 2014?
Low Arctic Sea Ice extents in Year_1 will not necessarily cause even lower Arctic sea ice extents in Year_2. Low extents in Year_2 will not cause even greater losses in Year_3. (Overall, the Royal Society did accept an assumed total loss of Arctic sea ice some time in the future. ) Sereze’s long-publicized “Arctic Death Spiral” is rejected. Each year’s arctic sea ice may increase (or decrease) from the preceding year’s total independently.
Unusually LOW sea ice extents in September cause extra heat losses in Oct-Nov-Dec, which often causes unusually HIGH sea ice extents in March = the next season’s maximum.
Unusually HIGH sea ice extents in September mean LESS heat loss over the Oct-Nov-Dec-Jan freezing periods, and thus higher than normal sea ice extents the next March-April.
All sea ice that melted one year will definitely re-freeze the next winter. It may be less thick, but it will all re-freeze. Normal sea ice in September indicate normal sea ice extents in March-April the next year will be likely.
So, is this conclusion by the Royal Society backed by the observed Arctic sea ice plots?
Bluntly, looking at the trends over time? Yes, the Royal Society has verified what we here at WUWT have maintained for a while: High Arctic sea ice extents in September cause greater heat loss over the following winter, and unusually high sea ice extents the next March-April.
Now, why does the opposite actually occur?
Unusually high sea ice extents in March-April often lead to unusually low sea ice extents in September.
I am open to comments and observations. Logically – You would assume greater amounts of solar energy are reflected from the increased sea ice area, less heat is absorbed over the Arctic summer months, and so there is less melting in July-August-September, and so the sea ice area in September is expected to be even higher.
But that scenario does not occur.
Unusually “high” Arctic sea ice extents do not often occur in March-April. Those spikes that have occurred stand out in the record above. Logically, one would expect the “extra” sea ice to remain in May-June-July, and so reflect extra sunlight otherwise absorbed into the Arctic Ocean, and thus cause unusually high sea ice extents in September. But “high” March-April sea ice anomalies are almost never followed by a “high” Arctic sea ice minimum in September.
Why do we not see them?
Or, is that the missing “excess” sea ice in March to blame for the “loss of sea ice” so-often blamed as a symptom of “Global Warming”?
The Arctic sea ice anomaly “2 standard deviation” band changes from month to month – going from a high of +/- 1.0 Mkm^2 in September minimum to a substantially lower +/- 0.5 at maximum in March.
But, from 1979 to early 2000, the Arctic sea ice anomaly declined slowly, but remained within 2 std deviations the entire period. It then took a rapid drop, then oscillated widely but always around an “average” lower level of -1.0 Mkm^2 in 2005-2015.
Why did that happen? Why did it drop so much more rapidly – when global average temperatures have NOT dropped, then, why did it oscillate so much around a lower average level?
Odd, this planet we live on.