Sea Ice North: The new field of ice-free Arctic Ocean science
Sea Ice North: The new field of ice-free Arctic Ocean science
I recently read a paper in Physics Today entitled The Thinning of Arctic Sea Ice by R. Kwok and N. Untersteiner. (Nice essay by Untersteiner) This paper was written for a general scientist audience, and provides a good summary of the state of the science. The primary focus of the article is on understanding the small change to the surface energy balance required to explain the increased rate of sea ice melt in the summer. Some time ago I wrote a few blogs on Arctic sea ice; they can be found here and this one is most relevant: Sea Ice Arctic.
When the IPCC Assessment Report was published in 2007 the Arctic sea ice was in visible decline. In the summer of 2007 there was a record decline that caught the attention of both climate scientists and the broader public. As suggested in Kwok and Untersteiner immediately following the release of the 2007 IPCC report papers started to appear about how the IPCC synthesis had underestimated the melting of both sea ice and ice sheets. Much of this underestimate could be summed up as simplistic representation of the dynamics of ice melting. For example, brine-laden sea ice floating in salty sea water turns over. Snow gets on the top. It melts, then there are puddles and ponds that can flow down into ice. Simplistically, and I am a simpleton, it’s like a pile of ice cubes sitting in a glass versus stirring those ice cubes, or blowing air over the ice, heat gets carried around and ice melts faster.
The presence of large areas of open ocean in the Arctic is new to us. It motivates new research; it motivates claims to newly accessible oil, gas, and minerals; it motivates new shipping routes; it suggests changes in the relationships of nations; it motivates the development of a military presence. (All things Arctic from the Arctic Council) The natural progression of scientific investigation starts to explore, describe, and organize what is to us modern-day humans: a new environment, new ecosystems, and new physical systems. For example, the Mackenzie River now delivers a massive pool of fresh water into the ocean. Fresh and salt – big differences to flow in the ocean because the density is different; big difference to the formation of ice because the freezing temperature is different; and big differences in the plants and animals in the water.
Compared with trying to attribute the contribution of global warming to a particular weather event, it is easier to link the recent, rapid decrease of sea ice to a warming planet. The freezing, melting and accumulation of ice require persistent heating or cooling. It takes a lot of heat for a sustained period to melt continental-size masses of ice. Historically, the sea ice that was formed in the winter did not melt in the summer and there was a buildup of ice over many years – it accumulated; it stored cold. Around the edges of this multi-year ice are areas where the sea froze and melted each year. The melting of multi-year ice, therefore, represents the accumulation of enough heat to counter years of cold. The movement, poleward, of the area where ice freezes and thaws each year is the accumulation of spring coming earlier. The requirement for energy to persist and accumulate to affect changes in sea ice reduces the uncertainty that is inherent in the attribution of how much global warming has impacted a particular event.
Understanding the detailed mechanisms that provided the heat to melt the ice remains a challenge. (This is the real point of in Kwok and Untersteiner) We know it takes about 1 watt per square meter of energy to melt that much ice that fast. This could be delivered by the Sun, transported by the air, by the ocean, by warm water from the rivers of Canada and Siberia, by snow – yes, snow is energy. Once the ice is gone in the summer, then the ocean can absorb heat from the Sun. If there is growth of phytoplankton or zooplankton, then they might enhance the absorption of energy – yes, life is energy. Ocean acidification might change. The natural question that arises – do these processes that are active in this new environment work to accelerate sea ice melting or might they contribute to freezing of water. What are the local feedbacks? (This is above – see below.)
Another study that is of interest is the paper in Geophysical Research Letters, Recovery mechanisms of Arctic summer sea ice, by S. Tietsche and colleagues. This is a model study. With a model the scientist owns the world and can prescribe what it looks like. In these numerical experiments, the Arctic is prescribed with no ice. Then whether or not the ice recovers is explored. In these studies the ice does recover. The ocean does indeed take up extra heat in the summer, but it gives it up quickly in the fall. This is followed by the formation of first year ice in the winter. The ice-albedo feedback that might let the ice melt runaway is limited. Tietsche et al. conclude that it is not likely that Arctic sea ice will reach a tipping point this century.
This does not mean that summer ice loss will decrease. This does not mean that there will not be huge changes in the Arctic. This only says that it still gets cold in the winter.
Models: One of the things I like about the Kwok and Untersteiner paper is their brief discussion of models. They point out that none of the models available for the 2007 IPCC assessment were able to predict the rate of sea ice decrease. Looking forward, they state that the model projections for 2060 range from no sea ice in September to more sea ice than is observed today. The Tietsche et al. paper is a focused model experiment – not a climate projection. It is also a model result that, perhaps, helps to understand the differences in the 2060 projections. That is, how is the recovery of sea ice in the autumn represented in the projection models?
A couple of other points: First, the amount of energy needed to cause the observed melting in sea ice is 1 watt per square meter. If you calculate the amount of energy in the different factors at play in melting of sea ice, then the numbers are 10s of watts per square meter. As suggested above, there are many reservoirs of energy – the Sun, rivers, etc. So when we look at the different ways 1 watt per square meter can be delivered to the sea ice, then there are several paths. The existing models tell us that with the increased heat due to greenhouse gases, energy gets delivered to the Arctic and sea ice melts. The existing models say that there might be several different paths; it is likely, that several of them operate at different times. The second point: Of course the Tietsche et al. paper will enter as an isolated contribution to the political argument, Arctic “death spiral” – as will those of accelerated melt, New warning on ice melt.
r
Figure 1: Simplistic summary of Arctic sea ice
Useful links
Recent sea ice trends
Sea ice data
Rood’s Blogs on Ice
Reader Comments
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 — Blog Index
It's interesting to note just how warm 2011 has been so far across the U.S.. As of yesterday, record daily high and record daily high minimum temps (new records and ties) have outnumbered record daily low and low maximum temps by a lopsided 12,694 to 8,234, a ratio of 1.54 to 11. And save for those two February cold spells (indicated on the chart below by the deeep 'V' on week five), things would be even more lopsided; since February 11, highs have outnumbered lows by 11,220 to 4,362, a ratio of 2.57 to 1. This chart shows cumulative highs and lows by week for the year-to-date. Pretty incredible:
Of course, a few weeks or even months of lopsided record highs or lows doesn't really signal anything, but over time, one would expect a roughly 1-to-1 ratio between record highs and record lows. But that's not happening; the ratio increases ever decade--a fact made all the more telling when one considers that to set a new record high, the previous record has to be broken.
IOW: it's warming up. Rapidly.
How could one not possibly question the GISS, after what is now being seen with the GISS March 2011 Anomaly in C Greenland VS. the RSS C Greenland Anomaly.
Here we have the GISS using the base temp of 1979-2000. Note the large positive anomalies over C Greenland.
Note that RSS has extreme negative anomalies in C Greenland. Why could the GISS have such erroneous temperature readings, when compared to the satellite data? Perhaps it's just because their way of extrapolating data from the Arctic just doesn't work so well.
I don't see how the GISS can possibly think that Greenland could have an anomaly of +2 when the PV was over Greenland, and when there was a very nice trough with 850 mb Temps being -30 to -35 Deg C throughout most of March.
I also like that on all advocate based graphs, that it always stops in 2000. What's wrong with showing the raw data since then?
Sea Level appears to be the lowest it's been in 5-6 years, but at least part of it is likely due to La Nina. Quite interesting though that we have lower Sea Levels than 2008, and 2008 was cooler globally, though on AMSU at 14,000 feet, we are currently much cooler than 2008 at the moment.
The Continental US is 2% of the Globe. Not a very convincing argument if you want to convince someone that this is due to Global Warming. More likely, it's due to the +AO/+NAO.
I am reading a nice book by Dr. Roy W. Spencer called "Climate Confusion" and he puts the terms very clear and simple if a lay person were to read his book. A few years ago, he and Professor John Christy decided to do a experiment by comparing the temperature record of the United States, to the Global Temperature Record. This is what he got. Spencer writes, "The resulting correlation was just about zero. No relationship. Even averaged over the entire United States, heat waves and cold waves were unrelated to globally averaged conditions" (Spencer, 16).
There you have it Cat5
You were saying...?
If they are comparing March 2011 to different time periods, that would explain the discrepancy.
Okay... where is the statistically signficiant trend in the graph I posted...?
Or maybe I'm the one who needs glasses? But it looks to me like there is data beyond 2000, ending around 2003/2004.
Nice try. And if we were talking about a single year or even a single decade, I'd agree with you. But it would take a special kind of person to look at decade after decade after decade with rising ratios of record highs to record lows and say, "Nope, nothing there."
No, they both use the same baseline. Even if it were different time periods, the temperature discrepencies are 6 Degrees Celcius. This adds onto my doubt about the GISS' extrapolation method to get data for the Arctic.
I'm sorry that verified scientific data scares anyone; that's not my intention at all. I merely present science fact, and hope it will cause a stir to action, not head-in-the-sand fear.
I'm going to stop playing your silly guessing game and just cut to the chase: Yes the current rising sea ice levels pale in comparison to the sea level rise during the ending of the ice age.
However, that doesn't detract from the fact that sea levels are rising. Not at all. And that's what Cat5hurricane was asking for, was it not?
It is still 7-8 years old, which doesn't help your case.
And we have no records for past interglacials, so there is no evidence that this is not beyond the natural variation.
You think "Watts Up With That" is more knowlegable than NOAA? LOL
It's no different than arguing with a little brother; in the end you are getting no where.
Graphing raw data does not have to do with anyone's intelligence.
The graph didn't end in 2000, like you claimed they always do, so it proves your case wrong nonetheless.
Either way, your graph helps
we only lack specific evidence telling us how much we are contributing.
Right. Sea Level has continued to rise slightly when one takes a look at the satellite data, but when one takes a look at the WHOLE trend in paleoclimatological data, there is no statistically significant trend, and what we are experiencing now with Sea Level Rise. It is not beyond the natural cycles.
Certainly not entirely, for we are at least partially responsible for the present warming.
Why is all of the Landmasses pink? lol
There are a few differences: We have a La Nina in 2011, but 2005 didn't, which could spell perhaps an active hurricane season this year.
I am thinking the warm hot moist air coming off the GOM is 1/3 of the problem we are having with severe weather and tornadoes.We need to cool it a bit.
Sea Levels are the lowest in 6 years, which solidifies the skeptic's claims of a plateu in recent years, yes, the graph does tell.
Ah, again you misunderstand. My explanations aren't for the denialists who linger around here; they are instead for the undecided or simply curious who stop by to learn. Answering falsehoods with scientific truth can be a thankless job--like arguing with an intransigent little brother--but it must be done. You're certainly free to ignore them, but I may be operating under a different mandate than you, so I can't. I just can't.
And yet the overall trend is rising.
Global warming refers to a warming climate. Climate = average weather conditions over a period of time. Typically climate is measured in 30 yr intervals. But it can be as little as 10, or as many as 100.
However, it is never expressed as one year.
Which is why the little plateau you're pointing out is entirely irrelevant. Great attempt though.
Ah, I see. Well, to each his own
A blogger to refute a peer reviewed paper... LOL
It is outdated.
+AO Ridge in Russia. Nothing new there.
But if you really do dislike that graph, I'll use your graph
Just roughly going over the graph, you can see there are a few plateaus, and even a few drops. AND YET IT'S STILL RISING.
Need I prove you wrong again?
At the end of the day snowlover, you proved nothing.
1. Earth is still warming.
2. Sea levels are in fact rising.
3. Humans are still at least partially responsible
You achieved nothing.
I thought for once I had a reasonable opponent.
oh well
Reuters Article...
When are we going to stop being stupid?
And he seems to think you have him on your ignore
Viewing: 1 - 51
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 — Blog Index