with Peter Sinclair
Videos from the National Snow and Ice Data Center make clear (again) just how bogus this denial talking point is.
You can also show them my own video on the subject, below, if they haven’t seen it…
The fact is that Antarctic sea ice set a record in 2012, and was consistently above “normal” (average) the entire year.
But what is more important is the latitude of Antarctic sea ice compared to that of Arctic ice. Because Antarctic (really, Southern Ocean) sea ice is at less extreme latitudes, it receives sunlight at a less acute angle than does the Arctic sea ice, which makes it more important as a climate feedback mechanism.
uh huh. right.
Spend some time looking through the graphs at the link below.
You’ll quickly find that the Antarctic sea ice extent was within the margin of error and not significantly greater than the median for the equivalent month for any of the last 30 yrs.
Antarctic LAND ice, on the other hand, has been melting dramatically. And melting land ice DIRECTLY increases sea levels.
That’s a common misconception, supersaiyanmagus. There’s no melt in Antarctica (except where the ice meets the sea). The famous moulins seen in the summer in Greenland are not found in Antarctica. Rarely, unusually warm weather may cause a bit of localized surface melt, but it promptly refreezes, and does not contribute to sea level rise.
Antarctica gains grounded ice mass through snowfall, and loses it through glacial movement and calving, and sublimation. But it is just too darn cold for the ice to melt.
A common misconception is that warming necessarily causes melting. It doesn’t. At one atmosphere pressure, ice won’t melt below 0°C. Where the the temperature is -60°C, even 50°C of warming won’t melt the ice.
That makes it hard to predict the behavior of the Earth’s great ice sheets. Extremely cold air holds so little water vapor that there’s very little snowfall when it’s extremely cold. If the air warms, snowfall may increase, accelerating the accumulation of grounded ice mass. On the Greenland ice sheet, where Glacier Girl landed on the Greenland ice sheet, about 264 feet of ice accumulated in just 50 years! That’s an average ice accumulation of nearly 2 meters per year.
OTOH, where ocean water meets glacier ice, if the water is above 0°C (remember, seawater freezes at about -2°C!), the warmer seawater will warm and melt ice at the interface between the two. The rate depends on water temperature and currents: warmer and/or faster-moving water will melt more ice, cooler or slower-moving water will melt less.
Whether Antarctica is gaining or losing ice mass is disputed. Indirect inferences of ice mass from GRACE satellite measurements of the Earth’s gravity field led some researchers to conclude that Antarctica is losing ice mass, but ICESat measurements of ice surface elevation indicate that it is gaining ice mass. Both types of measurements can be confused by land movement, but, in general, the ICESat data is a better indicator.
One thing we know for sure: the net effect of the various contributors to sea level rise has been no increase at all in the rate of sea level rise in response to the last ~3/4 century of rising GHGs. Plus, we know that two other anthropogenic factors, groundwater depletion and decreased reservoir impoundment, should have contributed to an acceleration in sea level rise over that time period, but no such acceleration occurred. So if the contribution to sea level rise from Greenland is increasing, then we know that it is is more than balanced by decreasing contributions to sea level rise from other sources.
actually, you can see some very famous moulins on the satellite pictures of Larsen B just before it collapsed
this has lead to a very marked speed up of the glaciers that the ice shelf was buttressing, and
is a leading example of how the ablation of coastal ice shelves is outstripping inland
accumulation in antarctica.
moreover, I would encourage anyone to follow your link to the “no melt in antarctica” quote, and listen to the remaining 6 minutes or so of Dr Rignot’s explanation. I think this fits the definition of “cherry pick” so completely, that I would use this in a class to illustrate the concept. Except, I’m not sure whether that should be a climate science class, or a psychology class, because its not clear whether you are consciously trying to deceive others, who you hope will not actually view the video, or pathologically bent on deceiving yourself.
Thanks, Peter, for “approving” my previous msg that was languishing in “moderation.”
Ice Shelves are floating ice, not grounded ice. We were talking about the ice sheets: grounded ice. When grounded ice melts (above sea-level), if it finds its way to the ocean w/o refreezing then it increases sea-level. When floating ice, such as an ice shelf, melts, it does not affect sea level (though when an ice shelf breaks up or melts or grows it can affect the rate of glacial movement “upstream”).
I, too, encourage anyone following this conversation to listen to Dr. Rignot’s full explanation. I didn’t “cherry pick,” and, unlike you, I didn’t augment his words with something he didn’t say.
He was perfectly clear, I don’t know why you couldn’t understand him. Perhaps you had difficulty with his accent?
Dave Burton: Do you have any numbers to back up your claim yet?
Last time you made this claim, you didn’t, so Tamino did the sums for you here.
Thank you for that link, thereoncewasawindmill! I’d never seen it before, and I’m astounded. They even wrote a poem about me!
They certainly had quite a conversation about “Dave Burton,” didn’t they? They were all certain that the reason I was being quiet was that I don’t know what I’m talking about. In fact, I had no idea that they were talking about me at all!
It’ll take some time to prepare a proper response, and when I do Grant Foster (“Tamino”) will probably delete most or all of it. He heavily censors his blog, presumably to minimize embarrassment, when it’s shown that he doesn’t know what he’s talking about (e.g., when he conflated satellite and tide-gauge sea-level measurements, to create the illusion of accelerated sea-level rise, even though both satellite and tide-gauge measurements show a slight deceleration in the rate of sea level rise).
That’s the reason that, when I have time, I like to join the conversations here, at ClimateCrocks. Peter, unlike Grant, and almost uniquely among climate alarmist blogmasters, lets me have my say.
In this case, though, I have to admit that most of what Grant has done is pretty good work, as far as it goes. However, there are a couple of rather obvious & important omissions in his calculations:
1. He seems to have forgotten about (or perhaps doesn’t know about) the fact that as the angle of incidence increases by which light strikes the water, the percentage of it which is reflected also increases. In other words, the albedo of liquid seawater varies with incident sunlight angle (and it does so much more than does the albedo of ice). That reduces the effective albedo difference between open water and sea ice at extreme latitudes. And,
2. Open water is more turbulent and loses much more heat through both evaporation and radiation than does water covered by a layer of ice. That means that at night, and when the sun is low above the horizon (i.e., especially at more extreme latitudes), the lack of sea ice associated with warming temperatures acts as a negative feedback. (Note: the Arctic and Southern Oceans are always losing heat via radiation. The reason they’re as warm as they are isn’t mainly due to absorbed sunlight, it’s due to water and air currents carrying heat there from less extreme latitudes; were it not for that transported heat, the Arctic would be as cold as Antarctica.)
These factors reduce net albedo-based positive temperature feedback to a greater extent at the more extreme latitudes of Arctic sea ice than at the less extreme latitudes of Antarctic sea ice. But Grant did not take these factors into account in his calculations.
BTW, over the years there’s been quite a bit of conversation about these topics at WUWT. You might find it interesting. Here’s an attempt at a Google search to find some of it:
“…as the angle of incidence increases by which light strikes the water…”
“…as the angle of incidence by which light strikes the water becomes more acute…”
“…as the angle of incidence decreases by which light strikes the water…”
Except you’ve still failed to provide any numbers to support your case.
And I’m afraid your new argument doesn’t stack up. Go to the ocean albedo finder here:
and find out how big a difference you get in ocean albedo with latitude – the absolute maximum difference is only around 0.1 between arctic and antarctic ice latitudes.
So you’re looking at only about a 10% difference versus sea ice albedo.
But convince us otherwise. Do the math.
I don’t know if this makes much of a difference, but when you build your absorption as a function of incidence curve, you might also consider that as the angle of incidence increases for a given pathway of light, with respect to the surface of the earth, the amount of atmosphere that such light travels through also increases, which then increases the probability that the atmosphere will absorb more from such. That then further begs the question of how such high incidence light, once it does reflect off the sea/ice surface, interacts with clouds: Is a higher magnitude of this particular pathway of light grabbed by clouds and re-radiated downward?, etc..
Both of Dave Burton’s comments are false. Tamino showed why Arctic sea ice loss has a much larger impact on albedo than Antarctica here:
And the 2012 Arctic sea ice extent was low starting in June, through the end of 2012. I’m pretty sure that “the entire year” is more than 5 months long.
Dana, w/r/t your first criticism, Tamino goofed.
W/r/t your second criticism, I said, Antarctic (not Arctic) sea ice ran high all year.
Do you mean that Antarctic sea ice was unusually high all year long?
That doesn’t match up with the NSIDC graph animation – see link below
Doing a month-by-month comparison to other years shows only trifling disparities.
[…] Videos from the National Snow and Ice Data Center make clear (again) just how bogus this denial talking point is. You can also show them my own video on the subject, below, if they haven’t se… […]
Dana in its post on SSc mainly cites Notz & Marotzke (2012, http://onlinelibrary.wiley.com/doi/10.1029/2012GL051094/full).
I still can not convince Dana for precise analysis of the papers, which cites. And there are these final conclusions.
“Given that both time series display a trend, the magnitude of this correlation [CO2 – arctic ice] must of course be interpreted carefully.”
“Note that the same reasoning allows us to conclude that changes in CO 2 concentration are not the main driver for the observed sea-ice evolution in the Antarctic. With no clear trend in the sea-ice extent there, there is virtually no correlation with the increasing CO 2 concentration. This underpins the fact that in the Antarctic, sea-ice extent is at the moment primarily governed by sea-ice dynamics. I n contrast, in the Arctic the sea-ice movement is constrained by the surrounding LAND MASSES and the thermodynamic forcing becomes more relevant there.”
“Strength” CO2 is here so maybe multiplied and is a multi-many times “… by the surrounding land masses …” and of little significance for example the Chukchi Sea (McKay et al., 2008, (http://bprc.osu.edu/geo/publications/mckay_etal_CJES_08.pdf). “If both the observed and reconstructed time series are correct, then the last part of the 20th century must have been particularly cold […] compared with the mid- to late Holocene in the Chukchi Sea, which is opposite to what is seen in the eastern Arctic and northern Baffin Bay (e.g., de Vernal et al. 2008). This hypothesis implies a STRONG REGIONALISM in climate changes over the Arctic …”
As we can see, each external factor (also effect of CO2) will be amplified by the AA.
The work of N & M are analyzed external factors for example AO. There is cited Rigor (2002, http://seaice.apl.washington.edu/AO/) – “the memory” of the winter AO determines the arctic climate in spring and summer.
Let us look at this figure of the winter AO: http://www.arctic.noaa.gov/detect/detection-images/climate-ao_nov-mar_2011-600.png (now we have a significant advantage years with a positive AO) and cite this work: () Beer et al., (2006, http://ruby.fgcu.edu/courses/twimberley/EnviroPhilo/SolVar.pdf):
“… the climate system has the potential to respond significantly to even VERY WEAK forcings and that this response may depend strongly, not only on the amplitude, but also on the duration of the forcing with potentially larger effects for longer lasting or repeated forcings.”
Lin et al. (2009., http://www.atmos-chem-phys-discuss.net/9/24731/2009/acpd-9-24731-2009.pdf): “The range of feedback coefficient is determined by climate system memory. The longer the memory, the stronger the positive feedback.”
“According to the findings of the working group, the AMOC predictive skill arises predominantly from the basin-wide upper-mid-ocean geostrophic transport. The results of the study demonstrate that the skill of climate prediction arises not only from the large ocean thermal inertia, but also from the LONG TIMESCALES OF INTERNAL OCEAN DYNAMICS.”
Thus, this factor also – not included by N & M – may operate with a delay in the same direction as CO2. How big gives RF? Our knowledge on this subject is still very small, but: Sejrup et al., (2010, http://www.leif.org/EOS/2010JC006264.pdf):
“The correlations are synchronous to within the timescale uncertainties of the ocean and solar proxy records, which vary among the records and in time with a range of about 5–30 years. The observed ocean temperature response is LARGER than expected based on SIMPLE THERMODYNAMIC CONSIDERATIONS, indicating that there is dynamical response of the high‐latitude ocean to the Sun.”
Clegg et al. (2011, http://www.pnas.org/content/108/48/19299) “These results illustrate nonlinear responses of summer temperatures to Holocene insolation radiative forcing in the Alaskan sub-Arctic, possibly because of state changes in the Arctic Oscillation and El Niño-Southern Oscillation and associated land–atmosphere–ocean feedbacks.”
In addition, we have now meandering jet stream (one of the possible causes – the recent strong solar activity minimum + CO2 warming – the AA …) additionally strengthening atmospheric-land blockade – heat “wanders” to the Arctic Sea.
… and I can not convince Dana to expand the base of the cited references …
For me the debate between supporters and skeptics AGW theory as to the existence and cause rapid melting Arctic ice is simply not important. The most important is the continued Arctic warming effect (beautifully presented above dynamic melting of Arctic sea ice).
http://www.sciencedaily.com/releases/2012/07/120716214457.htm: “… during warm interglacial periods the effect of a fresh surface ocean on the AMOC may be muted.” “A series of interconnected processes in the North Atlantic, known as polar amplification, could cause the Arctic to warm up faster compared to the rest of the world. It could even lead to ice-free conditions in the Arctic.” “Climate models favoring polar amplification use the Eemian as an analog of the present. In a new study, Bauch et al. compare reconstructed temperatures and water masses from two sediment cores that record the flow of meltwater in the subpolar and polar North Atlantic over the past 135,000 years. They do not find evidence of extreme warmth in the sub-Arctic during the Eemian interglacial period.” “Their finding also challenges climate models that predict extreme warmth and ice-free conditions in the Arctic in response to greenhouse gas warming in the 21st century.”
Of course, the insolation NH was, at the time, slightly different, but yet Sun …
Changes in the climate is not necessarily only across the rectilinear curves, exponential, logarithmic, nonlinearly – jumping (up) … and sometimes they are oscillating. Further warming for example affecting the AMOC can – paradoxically – to reverse the trend – increase the area of sea ice in the Arctic. And over this possibility we should be wondering.
I therefore confirm the opinion that Antarctica – such as weight loss ice sheet, is much better evidence to evaluate the strength of progressive warming, compared to the fast melting Arctic sea ice.
…sorry was meant to be: “heat faster and further “wanders” to the Arctic Sea.
Ice Sheet Loss at Both Poles Increasing, Study Finds:
“In contrast, the overall loss of ice in Antarctica has remained fairly constant, with the data suggesting a 50-percent increase in Antarctic ice loss during the last decade.”
That’s at odds with the ICEsat measurements:
Zwally, et al (2012), “Mass Gains of the Antarctic Ice Sheet Exceed Losses.”
I think rignot addresses this
Yes, he said, “There’s no melt in Antarctica.” (He said it several times, the first time at about 1:50.)
I think you should listen to it again.
what he is saying is that at the high levels of the antarctic ice sheet,
things aren’t melting.
the ablation in antarctica is happening through speeding up of
glacial runoff at the edges, which is more a function of ocean temps, and is
large enough to make antarctica in net negative balance, according to the IMBIE group he mentions – the definitive study.
Wrong: “at the high levels of” is your addition to what he said, Peter.
you are grasping at straws. review the IMBIE work that he says is authoritative.
moreover, your use of the denialist technique of grabbing at a nuance and deliberately twisting it into something it is not is quite glaring here.
I’m just telling you what he said. He said it repeatedly: “there’s no melt in Antarctica.”
He did not restrict that that flat statement to just “the high levels of the antarctic ice sheet.”
The only qualification he put on that statement is that he did say that there’s occasionally some melting on the Antarctic Peninsula, but he said that it just refreezes, so it doesn’t contribute to sea-level rise.
He also very reasonably speculated that the apparent ice increase could be just an artifact of fluctuating amounts of snowfall, and the fact that our satellite data record is still very short.
BTW, did you overlook this comment, which is still awaiting moderation (since January 8, 2013 at 2:16 pm)?
[…] 2013/01/03: PSinclair: Next Time Someone Tells you “Antarctic Sea Ice is Growing”, Show … […]
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