The Royal Society of New South Wales held a meeting on Saturday in Mittagong on ‘Global Warming and The Cosmos’. Speakers included the director of the Danish National Space Centre, Eigil Friis-Christensen, and Graeme Pearman, former head of the CSIRO Atmospheric Division and now a consultant with GP Consulting Pty Ltd and an advisor to Al Gore and Ross Garnaut.
Graeme Pearman and Eigil Friis-Christensen, Mittagong, April 5, 2008
Dr Pearman spoke first and focused on global warming from carbon dioxide as a “policy driver”. I was offended by the presentation.
Dr Pearman suggested that much of the 0.7 degree Celsius increase in the earth’s temperature over the last 100 years has occurred in the last 10 years. Yet the last really hot year was in 1998 and global temperatures have since plateaued.
Graph and fitted spline curve from 1979 through to February 2008, from Professors John Christy and Roy Spencer, University of Alabama, Huntsville
Dr Pearman referred to 95 and 99 percentiles as measures of the “proof of an hypothesis” in the same breathe claiming that that there was more than 90 percent proof that global warming is a consequence of greenhouse gas emission. Yet this 90 percent figure, sometimes used by the United Nation’s Intergovernmental Panel on Climate Change, is not from the testing of a falsifiable hypothesis but rather a political expression of the strength of opinion.
Dr Pearman began his presentation by suggesting that the break-up of the Wilkins Ice Shelf was a consequence of global warming. When I questioned him on this issue, he told the audience that Antarctica is warming.
Yet it is generally accepted and uncontroversial that 95 percent of the landmass of Antarctica has cooled over the last 20 years.
Image depicting the heating and cooling trends over and around Antarctica (1982-2003). Blue indicates cooling trends and red indicates warming trends.From NASA/Goddard Space Flight Center Scientific Visualization Studio.Data provided by Larry Stock.
There has been warming at the edge of the continent including where Wilkins Ice Sheet recently collapsed. The collapse could be due to global warming , oceanic volcanoes, and/or from internal stresses associated with the accumulation of ice in the bay.
———————————–
I am grateful to John McLean for information on temperatures in the vicinity of the Wilkins Ice Shelf and Joe D’Aleo for other temperature data, and to Bill Kininmonth and Garth Paltridge for information on the Wilkins Ice Shelf collapse.
I shall elaborate on the presentation by Dr Christensen in Part 2, to be posted in the next day or two.
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
http://newsbusters.org/blogs/matthew-vadum/2008/04/01/media-ignores-al-gores-planned-global-warming-profiteering
Gores motives are well explained by this– as for the others who knows?
Oh John Mclean you have done it again.
A good piece of work that casts grave doubts over the integrity of some of the alarmist nonsense being peddled by people employed in government agencies- yet again.
Couple of points of order
– call for the actual station temperatures – some have said “little change” in temperatures for Antarctica itself – need to quote that more authoritatively.
There is zero reason for the spline through the temperature series except preference – an upward straight line would be just as good. Indeed the trend on left hand side of the spline would be wrong. And without a formal prediction the trend on the right hand side “leading”. If you wanted to be “scientific” you should have 3 lines – the spline, a linear trend, and straight line over recent years – and leave it to the reader to decide.
“Do the NSIDC and BAS seriously believe that human activity caused irregular variations in
prevailing winter winds, or changes in cloud cover such as the abrupt shift in 1998?” – well don’t know about them but that’s the point actually – ozone depletion + GHG = changes in Antarctic circulation is the hypothesis
“Figure 4 shows some abrupt spikes in sea surface temperature, particularly during the southern
summer and a slightly warmer period from 1998 to 2004 but as before, variations in wind and
cloud cover are likely causes of these situations”
err yep – indeed gives the trend of some changes –
And given the speed in of discharge in western Antarctic glaciers discharging into the ocean (from decreases in the amount of sea buttress) – more or less supports the picture.
You can easily interpret the John’s findings either way. Depends how you want to portray it and what’s left in and what out.
“Absolute proof” – well you’re not going to get it early on in the AGW saga – why would you expect to? “God” isn’t going to make it easy for us to work it out.
Gotta go !
Jennifer, that spline curve looks all wrong. It doesn’t look like it is from the data, it looks like someone has hand drawn it in. Do you have the details about it? Still with the “no Global Warming since 1998”? It’s not a requirement of the hypothesis that the warming be constant, it’s only ever been about trends.
This spline, is it a cubic spline? It doesn’t look like one. And I thought when using splines the start and end data points should match the spline. Why do the end points in this spline lie above the start and below the end? The spline looks too simple to be a valuable interpolation tool. The point of using a spline is interpolation between data points and smoothing. You don’t need to interpolate here and the smoothing is way too extreme to be useful.
“Yet it is generally accepted and uncontroversial that 95 percent of the landmass of Antarctica has cooled over the last 20 years. ”
I don’t think it is… you need to update your Antarctica image. The one you have ends in 2003, this one goes to 2007.
http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17838
The science content of this article looks poorly researched. You seem to have only taken the parts that fit your political view and ignored more recent publications.
Seems we’re not the only ones receiving poor value for our tax dollar.
Mr T.,
Thanks for the link I didn’t realize there was an update. It is not reference at the image I used which is still at the NASA site.
And I find it difficult to reconcile the new image with the previous image.
The image I posted is 1982-2003. I have seen temperature data for Antarctica since 2003 and it doesn’t show any warming.
How do you explain the large change?
Also even the IPCC fourth assessment report (2007) said there was no warming at the Antarctic?
an upward straight line would be just as good.
No Luke they are not straight lines lead to discontinuity and nature does not work like that. Especially not something with earth’s thermal inertia.
PS.
More questions:
Q.1, Mr T’s link includes comment that:
“Across most of the continent and the surrounding Southern Ocean, temperatures climbed. In some places the rate of warming approached a tenth of a degree Celsius each year, which would translate to more than two degrees over the entire period.”
… which period?
Q2, And how can this be reconciled with the 1982-2003 image where there is clearly significant cooling over most of the continent for most of the period?
Q3, And when was the new image posted?
Quote:
“Dr Pearman suggested that much of the 0.7 degree Celsius increase in the earth’s temperature over the last 100 years”
Eyeballing the temp curve above I wonder where the 0.7 degree comes from?
Jennifer,
Q3 I am not sure when the image was posted, I assume sometime last year as it references a study published last year (so the image goes to the start of 2007 I believe).
Q2 Perhaps the middle of Antartica warmed? 🙂 Kidding of course!
It references this aritcle: http://www.cosis.net/abstracts/EGU2007/10892/EGU2007-J-10892.pdf
Perhaps they used this article to re-assess the temperatures in the interior? Or the way they interpolate between data points.
I don’t know so I shouldn’t speculate.
Q1
“This image illustrates long-term changes in yearly surface temperature in and around Antarctica between 1981 and 2007. (An earlier version of this map is pictured in a previous posting on the Earth Observatory.) ”
It links to your earlier image in that paragraph.
Also:
“The map is based on thermal infrared (heat) observations made by a series of National Oceanic and Atmospheric Administration satellite sensors. Because the satellite is observing energy radiated from the Earth’s surface, the image shows trends in skin temperatures—temperatures from roughly the top millimeter of the land, sea ice, or sea surface—not air temperatures.”
Which may indicate why it’s different from air temperatures. Which probably answers Q2, although your original image is also skin temperatures not air temps.
The 4AR says:
“It is likely that there has been significant anthropogenic
warming over the past 50 years averaged over each continent
(except Antarctica) (Figure 2.5). {WGI 3.2, 9.4, SPM}”
So that’s not to say there’s been cooling, rather that hasn’t been significant Anthropogenic Warming over the past 50 years.
And that this is fine wrt AGW:
“Warming is expected to be greatest over land and
at most high northern latitudes, and least over the Southern Ocean
(near Antarctica) and northern North Atlantic, continuing recent
observed trends (Figure 3.2 right panels). {WGI 10.3, SPM}”
Lawrie, the curve given by Jennifer starts in 1979, not 1907.
The MSU data for the South Pole doesn’t show Dr. Perlman’s warming. Here’s South Pole Land + Ocean:
http://tinypic.com/fullsize.php?pic=ehrp3&s=3&capwidth=false
South Pole land:
http://tinypic.com/fullsize.php?pic=35bxmy1&s=3&capwidth=false
And South Pole ocean:
http://tinypic.com/fullsize.php?pic=2nle1yp&s=3&capwidth=false
I was at the Roy Soc meeting on Saturday and thought Pearman’s explanation of the Wilkins Ice Shelf collapse unconvincing. His explanation was that surface melt water had penetrated the ice sheet and undermined it’s integrity. No explanation was given where the heat came from to perpetrate this miracle, seeing the air temperatures in the Antarctic have never risen above freezing, as far as I am aware.
Also interesting was the audience reaction to the two speakers. I fully expected that they would be more supportive of Pearman than Friis-Christensen, but the reverse was the case. Pearman attracted not a little heckling and incredulous laughter. Friis-Christensen, on the other hand was more warmly applauded at the end, in spite of being softly spoken and struggling with the language.
Allen: . I fully expected that they would be more supportive of Pearman than Friis-Christensen, but the reverse was the case.
do you think that’s perhaps because AGW theories are losing traction?
Jan “do you think that’s perhaps because AGW theories are losing traction?”
Why would audience reaction be indicative of this? Is this argument by popularity now?
Mr T.
1. I shall have another look at 4AR as my memory says it actually says ‘no warming’ – perhaps in the summary for policy makers? What you have quoted is equivocal.
2. But I am very curious about the tremendous difference in the two images. Can we find some temperature series data for various localities in the Antarctic and get a better handle on this?
Indeed if there has been dramatic warming in the Antarctic over the last few years this is surely big news and goes against the global trend? But how does one reconcile this with the apparent increase in sea ice cover – or is my information on this also out-of-date? Something is a miss!
OK. I’ve just found and released Bob Tinsdale’s comment which had been caught in the Spam filter.
I agree that the image looks more like a drawing.
“Is this argument by popularity now?”
No Mr T, unless the audience has been loaded it may be indicative of public acceptance of the theory.
Hey Bob, can you give us a bit more background on those pics?
Bob, Jennifer, and others
“Dr Pearman suggested that much of the 0.7 degree Celsius increase in the earth’s temperature over the last 100 years”
The grpahs presented here only show from 1979, not the last 100 years.
Jan,
Public acceptance is pretty irrelevant to science. It only matters to politics.
And in response to ‘marketing consultant’ and others regarding the graph of satellite data.
I don’t have any problems with the graph or the fitted curve – but if someone gives me a bit more of an explaination as to what they think is wrong with it and their real name I will email Spencer.
The graph and my interpretation is broadly similar to the thermometer data including from Hadley and NOAA and statements made by the head of the IPCC – so I am not sure what you guys are on about. See here http://icecap.us/images/uploads/Correlation_Last_Decade.pdf and my two earlier posts on this issue http://www.jennifermarohasy.com/blog/archives/002863.html and the interview with Michael Duffy.
The temperatures shown in both pictures are skin temperatures of the surface of Antarctica and not air temperatures. Which makes of course a difference or at least can not be compared.
Secondly they write: “The scientists estimate the level of uncertainty in the measurements is between 2-3 degrees Celsius.” Of course both ways.
What does it say? More reflection by the Antartic surface? Time will tell.
Jennifer, I could be wrong – I downloaded the 4AR and searched for “antartica”. Antarctica was constantly mentioned as an exception to the general statements they made – but not that it was ‘cooling’
2) I think you may be mixing the surface temp anomaly with near-surface air temp anomaly. The data in the grpahs (provided by Bob et al) shows the air temp. The images both show skin temperatures. It’ll still be below zero. I don’t know if they have many air temp stations down there?
It is strange that they have changed so quick. The scale bars at the bottom are different too, the latter has a narrower range. It also starts two years earlier so maybe 1981 and 1982 were quite cold, so recent years look warmer? I would think it’s because it is based on a longer time, 25 years as opposed to 22.
I dare not downlooad this but:
http://svs.gsfc.nasa.gov/vis/a000000/a003400/a003490/index.html
Right at the bottom is an animation that shows the temp anomalies since 2003, which would encompass what you want. What does it show?
“Friis-Christensen, on the other hand was more warmly applauded at the end, in spite of being softly spoken and struggling with the language.”
It could be that he was applauded more because he was softly spoken and struggled with the language, not in spite of it.
Jennifer: “It could be that he was applauded more because he was softly spoken and struggled with the language, not in spite of it.”
It couldn’t have been the subject matter?
I don’t think so, given the semi-hostile reception to Pearman, although there may have been an element of courtesy to a visiting speaker.
Allen: . I fully expected that they would be more supportive of Pearman than Friis-Christensen, but the reverse was the case.
do you think that’s perhaps because AGW theories are losing traction?
Yes, I do, at last amongst those that count, i.e., practising and retired scientists, as the New York conference last month also attests. One can only hope the MSM and politicians follow suit before enormous political and economic damge is done.
Allen & Jennifer thanks I see you have somewhat different perspectives of audience response. I’m not sure what to make of it then so I’ll leave it there.
A whole lot of revisions (or nothing) going on?
3 periods in play:
1) 1982-2003; 2) 1981-2007; 3) 1982-2004 (linked)
Note: 1 & 3 are most alike.
2 indices of color map:
1) ? 2) -.1 – .1; 3) -.2 – .2 (blue-red)
Why the topic reference about “two (2) decades” when the map is supposed to be 1981-2007?
Why the change from 1982 to 1981? Well, 1981 Antarctic was cooler: land, ocean and both!
http://igloo.atmos.uiuc.edu/Antarctic.paper.chapwalsh.2005.pdf
Although a question about source of measurements exists — mixed instrumentation?
Until much of this is answered, and until we see the late 2007 and early 2008 data — may be lot’s of fuss over nothing or even cooling again? I will withhold a “cherry-pick” criticism, until we know more.
Jan and others,
The second comment about audience’s reaction was from Jennifer B – not from me (Jennifer Marohasy).
There were many skeptics in the audience and I would not have characterised the audience as particularly representative of the community.
And they weren’t responding to the manner of the presentations – many were hostile to Pearman and the content of his presentation.
Mr T.,
1. So the IPCC suggests that the Antarctic is an exception – but can’t bring it self to use the word ‘cooling’?
2. And Pearman tells us on Saturday that like the rest of the world it is warming?
3. And we have two very different images of Antartica from similar time periods from the same organisation?
Jennifer,
1. Not sure if Antarctica is ‘cooling’, maybe that’s why they don’t say it. And yes Antarctica is a special case, it has a high latitude and altitude so there’s not much point in saying “well the middle of Antarctica is cooling” because it’s over 2500m ASL, at 85 + latitude and has little ozone (so the upper atmosphere gets very cold). I think that it rates as a special case.
2. Certainly the coastal areas of Antarctica (and the Peninsula) are. Satellite skin surface temps show it generally is.
3. Similar aint the “same” though is it? They use different time periods, so you’d expect them to be different. And they’re not THAT different, also one shows from -0.2 to +0.2 the other shows from -0.1 to +0.1. Don’t be fooled by colour changes.
Mccall, interesting paper.
Figure 8 seems to confirm what Dr Pearman was saying – or at least confirm that Antarctica has warmed since around 1958.
Jennifer, the Hadley Centre did an analysis of sea ice extent at the poles, attempting to go back to the 1880’s and found that sea ice extent had diminished in the Antarctic from around 25 million km2 to the present level of between 15 and 16 million km2. That suggests the area has warmed over the last century.
http://www.agu.org/pubs/crossref/2003/2002JD002670.shtml
Sadly I can’t read it… Maybe you can get the whole thing?
Jennifer & J. B Ooops my apology.
“I would not have characterised the audience as particularly representative of the community.”
This tells me what I want to know i.e. we can’t sure from the audience response that there is a loss of traction from pro-AGW argument.
Thanks.
The text accompanying the image doesn’t inspire much confidence in the temperature measurements.
The references quoted are from 2002, and 2005. The 2007 reference refers to the west and east.
Paul, I don’t think the references are the data source, it says in the text that it’s satellite data; specifically “National Oceanic and Atmospheric Administration satellite sensors”… Maybe if you look at the NOAA website you may be reassured.
Also apparently Global Warming has started again, http://wattsupwiththat.files.wordpress.com/2008/04/rss_msu_mar2008_large.png
Boy is it hot outside 🙂
The divergence between the NH and SH continues in the MSU data.
Monaghan, A. J., D. H. Bromwich, W. Chapman, and J. C. Comiso (2008), Recent variability and trends of Antarctic near-surface temperature, Journal of Geophysical Research, 113, D04105, doi:10.1029/2007JD009094.
Antarctica ain’t warming.
Paul,
“Abstract
We compare new observationally-based data sets of Antarctic near-surface air temperature and snowfall accumulation with 20th century simulations from global climate models (GCMs) that support the Intergovernmental Panel on Climate Change Fourth Assessment Report. Annual Antarctic snowfall accumulation trends in the GCMs agree with observations during 1960–1999, and the sensitivity of snowfall accumulation to near-surface air temperature fluctuations is approximately the same as observed, about 5% K−1. Thus if Antarctic temperatures rise as projected, snowfall increases may partially offset ice sheet mass loss by mitigating an additional 1 mm y−1 of global sea level rise by 2100. However, 20th century (1880–1999) annual Antarctic near-surface air temperature trends in the GCMs are about 2.5-to-5 times larger-than-observed, possibly due to the radiative impact of unrealistic increases in water vapor. Resolving the relative contributions of dynamic and radiative forcing on Antarctic temperature variability in GCMs will lead to more robust 21st century projections. ”
I don’t understand how you get no warming from this? It says the observations are smaller than the GCM’s predict (by a large factor), but doesn’t mention cooling… Do you have the whole paper?
Wow published last Saturday, that’s quite a scoop Paul!
Oh, here’s the full (draft) text
http://polarmet.mps.ohio-state.edu/PolarMet/PMGFulldocs/monaghan_etal_grl_draft_2007.pdf
If you read it, and look at Fig 1 you can see the observed temp up to about 2000. Might be a vague warming… Doesn’t look like any particluar cooling… Looks kind of variable. Interesting that recent years have been more ‘extreme’ – both positive and negative (but more positive 😉 )
Looks more like a little bit of warming to me… What were the last 8 years like? Methinks it would show more red than blue.
Tamino pretty much lops the head off the Global Warming Stopped in 1998 canard here, using readily available GISTEMP and HadCRU data in a replicable calculation:
http://tamino.wordpress.com/2007/08/31/garbage-is-forever/
“All records correlate significantly with all other records during all seasons from 1982 to 2001. Near-surface temperature trends are statistically insignificant (p >0.05) on annual timescales within every data set analyzed, for both the longer (1960–2002) and shorter (1982–2001) periods.” Monaghan et al.
We’re talking about the Antarctic Wadard, but the measured global average temperature near surface record remains 1998.
And how do you get record levels of sea ice in a warmer Antarctic?
Its probably because I am an unqualified simpleton that I find it impossible to believe that Antarctica is getting warmer. I am quite sure I saw a graph showing that the Antarctic sea ice was 1.5 m sq kms more than this time last year. Last year was the record since satellite measurements began in 1979…..
Or does ice form quicker when its warmer?
hmmm nothing official on “record” Antarctic sea ice for March – April 08, but lots from same old same old blogs hey
Leave this place for a day or so and the mice play go to the top of the ladder in their upside down game of snakes & ladders
Paul Biggs, I was responding to Jennifer’s post. And, Mr T covered off the Antarctic thread for me.
Since you mention it though, perhaps the only thing to add is why conflate the Antarctica land mass with the sea ice that is the Wilkes Ice Shelves? There are two different systems influencing the sea-ice and the land mass.
Wadard – I’d prefer it if you avoided quoting pseudanonymous bloggers like ‘Tamino.’
West Antarctica is where there is warming, for a number of reasons.
Paul Biggs; don’t worry you have established yourself as the resident Thread-Nazi. I get the message.
I’ll note you omitted to discuss the mathematics and instead choose to attack Tamino, and quietly leave it at that.
Post up some peer reviewed papers from ‘Tamino’ so we can see where his expertise lies, please!
There is a significant warm bias in the flawed metric of ‘global average near-surface temperature.’ Try your maths on that.
Mr T kindly wrote:
“Lawrie, the curve given by Jennifer starts in 1979, not 1907.”
Now let me be up front and admit that I did not see this when I wrote my post.
But what difference does it make as the last decade or so is often claimed to be the hottest recorded in the last century or so.
Guess it depends on whether one takes the difference between the lowest (coldest) figure from the prior 1979 figures to the warmest in the last decade or so as the “warming”. This surely is a worst case value and as such a bit hard to arguably sustain.
OR
Takes the zero anomomly as the datum and looks to the current value which is also close to zero.
Maybe more realistic to take the peak spline value of about 0.3 deg.
As this 0.7 figure is regularly used would be interested in its origin (which I know I can find if I go look for it:-)
Just thinking aloud so to speak.
Does one detect a hint of shrillness in the utterings of the Warmers as they dig deeper into their ‘virtual reality war chests’ in an ever more desperate attempt to confound climate truth and reality. Desperate stuff to try and save their holy grail of AGW, as it sinks beneath the rising tide of factual real life climate data.
As for Graeme Pearman; he is an old leftie from way back. In the early 90’s while at the CSIRO he was an evangelist for ‘global warming’, and is currently involved in some loopy pink/green ‘climate coalition’.
Paul et al Re: sea ice.
The Hadley Centre released a study (which I linked to the abstract above) that showed that the sea ice in Antarctica prior to satellite measurements was typically in the region of 20 – 25million km2. This current years sea ice extent doesn’t seem particularly significant. Also note that temperatures are more likely to affect volume than extent (the Arctic is a good example of this). So the maximum extent isn’t a particularly good proxy for temperature.
Sid, any shrillness is in that paranoid head of yours.
Lawrie, it has been stated many times that the various climate models and the IPCC statements all talk about Antarctica not necessarily following the rest of the world in warming.
Paul, if “There is a significant warm bias in the flawed metric of ‘global average near-surface temperature.’ Try your maths on that.” why do people keep trying to match the sun’s effect to it? Why do people keep posting global average temp and comparing it to sunspot cycles? If it’s so poor, why do you keep using it?
Mr T, “:Sid, any shrillness is in that paranoid head of yours”
That “nazi” card playing Wadard strikes me as rather shrill.
“I was offended by the presentation.”
Of course you were.
Mr T – because ‘global average near-surface temperature’ is the favoured metric. It is influenced by climatic and non-climatic factors to varying degrees depending on the location of each station.
The recent McKitrick & Michaels paper has yet to receive peer reviewed comment:
http://www.jennifermarohasy.com/blog/archives/002599.html
There is no reliable temperature dataset for the Antarctica. MSU (UAH or RSS) only cover down to 70S latitude. There are only a handful of surface temperature stations in the Antarctic, resulting in gross interpolation to infer a continental temperature, let alone trend. And as someone noted above, the IR surface temperature satellite measurements (much different than the microwave sounding units) have accuracies of +/- 2-3 degrees C, after correcting for surface albedo. Do you really pay attention to sensor noise that is 20-50 times higher resolution than what the sensor is capable of providing? I don’t think so.
I am always interested in two facts about these colored contour maps of temperature anomalies. First, that the south pole warming always shows up around the coastline. That indicates ocean current-driven regional warming, yes/no? But oceans have shown stasis to slight cooling over the last 5 years according to Argo, so it is most likely regional warming due to ocean current patterns. Second, the color choices are not indicative of the absolute temperatures, and should be. How about a color index that varies across the visible spectrum in direct proportion to absolute temperature in degrees K. Deep purple would be -80 C and deep red would be +60C (that covers the temperature ranges measured on Earth, by the way). That means the temperatures in the antarctic should vary from a deep purple to a slightly less deep purple.
Recent Data On Surface Snowmelt In Antarctica
In the March 25 2008 issue of EOS, there was a News item by Marco Tedesco titled “Updated 2008 Surface snowmelt Trends In Antarctica”. It reports the following
Surface snowmelt in Antarctica in 2008, as derived from spaceborne passive microwave observations at 19.35 gigahertz, was 40% below the average of the period 1987–2007. The melting index (MI, a measure of where melting occurred and for how long) in 2008 was the second-smallest value in the 1987–2008 period, with 3,465,625 square kilometers times days (km2 × days) against the average value of 8,407,531 km2 × days (Figure 1a). Melt extent (ME, the extent of the area subject to melting) in 2008 set a new minimum with 297,500 square kilometers, against an average value of approximately 861,812 square kilometers. The 2008 updated melting index and melt extent trends over the whole continent, as derived from a linear regression approach, are –164,487 km2 × days per year (MI) and –11,506 square kilometers per year (ME), respectively.
Negative trends for the period 1987–2008 of the number of melting days (Figure 1b)
over the Antarctic Peninsula are observed at a rate down to –2 days per year for internal areas and about –0.7 days per year for coastal areas. Contrarily, positive trends (up to approximately +0.25 days per year) are observed on part of the Larsen Ice Shelf.
In East Antarctica, positive trends are observed over the Amery, West, Shackleton, and Voyeykov ice shelves, with values of up to +0.7 days per year for Shackleton and +0.8 days per year for Amery. Interestingly, the latter shows negative trends (down to –0.3 days per year) for internal areas but positive values for coastal areas.
Large-scale monitoring of ice shelves is an important task for many reasons: Though
ice shelves do not contribute directly to sea level rise, they play an important role in keeping the warm marine air at a distance from glaciers; and recent observations also suggest the buttressing effect of ice shelves in preventing acceleration of ice sheets. An increasing surface snowmelt over ice shelves might lead to persisting melt ponds, which, in turn, might contribute to ice shelf disintegration as liquid water fills small surface cracks. Depending on the amount of water and the depth of a crack, the water can deepen the crack and eventually wedge through the ice shelf. Along with surface processes, it is imperative to focus on verifying hypotheses regarding those processes occurring at the ice-ocean boundaries, such as, for example, the thinning of ice shelves driven by ocean-induced melting.
A color version of Figure 1 can be viewed in the electronic supplement to this Eos issue (http://www.agu.org/eos_elec).
This report seems to have otherwise been missed by the media (I could not find articles in a search on google news), but it consistent with the recent colder than average tropospheric temperatures in the Southern Hemisphere. The finding that
“The melting index (MI, a measure of where melting occurred and for how long) in 2008 was the second-smallest value in the 1987–2008 period…”
is quite an important observation and further reinforces what is at least a short term cooling of the climate system.
http://climatesci.org/2008/04/07/recent-data-on-surface-snowmelt-in-antarctica/
Now we’re talking about whether the Antarctic is warming or cooling?
Didn’t the GISS mob recently agree Antarctica was cooling but that this wasn’t in conflict with their models?
Correct!
Antarctica is Cold? Yeah, We Knew That
http://www.realclimate.org/index.php/archives/2008/02/antarctica-is-cold/
Despite the recent announcement that the discharge from some Antarctic glaciers is accelerating, we often hear people remarking that parts of Antarctica are getting colder, and indeed the ice pack in the Southern Ocean around Antarctica has actually been getting bigger. Doesn’t this contradict the calculations that greenhouse gases are warming the globe? Not at all, because a cold Antarctica is just what calculations predict… and have predicted for the past quarter century.
It’s not just that Antarctica is covered with a gazillion tons of ice, although that certainly helps keep it cold. The ocean also plays a role, which is doubly important because of the way it has delayed the world’s recognition of global warming.
(more…)
Tee Hee Hee!
Paul, I’m sorry but don’t expect me to start believing satellites 😉
BTW, as Pielke Snr noted, funny how this news article has been apparently ignored by the media having so recently reported on the Wilkins ice sheet.
It’s strange, people laughed at Dr Pearman when he talked about snow melting in Antarctica and yet here they are openly talking about how the melt is the second lowest in 20 years… I am wondering, do you take notes on what you believe?
Allen Ford: “I was at the Roy Soc meeting on Saturday and thought Pearman’s explanation of the Wilkins Ice Shelf collapse unconvincing. His explanation was that surface melt water had penetrated the ice sheet and undermined it’s integrity. No explanation was given where the heat came from to perpetrate this miracle, seeing the air temperatures in the Antarctic have never risen above freezing, as far as I am aware.”
And yet “Surface snowmelt in Antarctica in 2008, as derived from spaceborne passive microwave observations at 19.35 gigahertz, was 40% below the average of the period 1987–2007. The melting index (MI, a measure of where melting occurred and for how long) in 2008 was the second-smallest value in the 1987–2008 period, with 3,465,625 square kilometers times days (km2 × days) against the average value of 8,407,531 km2 × days (Figure 1a). Melt extent (ME, the extent of the area subject to melting) in 2008 set a new minimum with 297,500 square kilometers, against an average value of approximately 861,812 square kilometers. The 2008 updated melting index and melt extent trends over the whole continent, as derived from a linear regression approach, are –164,487 km2 × days per year (MI) and –11,506 square kilometers per year (ME), respectively.”
Interesting that people laugh at what they don’t understand.
I’m sorry, Jennifer. I disappeared for a day. The source of the SoPol graphs is MSU (UAH):
http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt
They’re temperature anomalies that are over a month old so they don’t include Feb 2008.
Regards
Bob: old so they don’t include Feb 2008.
they don’t include March. Small point.
Something for all to digest:
http://www.columbia.edu/~jeh1/2008/TargetCO2_20080407.pdf
Mr. T-
Re: warming or cooling in the antarctic, trends are small so my point was start end point matters. The cooking that is going on is because this behavior is and has been counter to the flagrant doomsday claim of the AGW dogma. Why even antarctica’98 did not participate in even close to record high temps.
And I will submit (wager anyone?) that 2008 will hit antarctic hard on the cold side — wiping out any cherry-picked or otherwise short term warming that the hockey team is pushing.
Mr Wadard – as for Tamino, you really should read ClimateAudit. Tamino has been eviscerated on more than one occasion, and will be likely again on this latest torture of the GISTEMP & HadCRUT data. FWIW, and setting aside his sock-puppet, he appears to be on the hockey team, and not independent of their own tortuous mathematics.
http://www.climateaudit.org/?p=2970
http://www.climateaudit.org/?p=2920
mccall, I don’t think we’ll see much wrming in Antarctica for millions of years personally. It’s cold, high altitude all point to it being icy for a long time to come.
But, it’s also mostly irrelevant. Does it matter that Antarctica bucks the trend? the models indicate that it will not warm anytime soon, the IPCC freely admit that observations and projections don’t really work for Antarctica.
For some reason people on this blog see a non-warming Antarctica as proof AGW is false. Not sure why…
Another thing, why would being “eviscerated” on blog mean anything? Just because people get something wrong doesn’t mean they are wrong for all time.
Mr T, “For some reason people on this blog see a non-warming Antarctica as proof AGW is false.”
Perhaps if you remember that some people see the cracking up (calving?) of ice shelves and glaciers as evidence of warming then perhaps you’ll understand why.
Jennifer, I was offended by that spline curve. I think last time ( and hopefully the last) you let it loose you claimed you preferred the data to models, apparently and ironocally ignorant that the choice of curve is a choice of model is a choice of hypothesis about how the world works. So hoist with your own pet graph. To assume such a curve was somehow appropriate is simply preposterous in the context of someone who does not like models.
Bazza, models have their purposes, including the UN climate models, but they also have their limitations and these need to be acknowledged. as regards the graph from christy and spencer i understand several people don’t like it. but i still don’t understand your and others specific problem. could you please explain what you consider inappropriate about the graph.
PS. How exactly would you like the data plotted?
Jennifer: How exactly would you like the data plotted?
A linear regression from August 92 to January 97 would probably make him happiest. The curve is fine as it shows the longer term variations underlying the annual, ENSO and PDO cyclic variations which the linear regressions do not show.
Jennifer the problem with the spline curve as it doesn’t aid in the understanding of the underlying graph. The spline curve is of a too low frequency. Splines are made by interpolating between data points. It looks like they have used about 3 points. Do you have the source of the graph? I looked up all the Spencer and Christy publications I could and none had that graph (it does go all the way too 2008, so I would suggest it hasn’t been published).
It’s a bit hard to say what is wrong with it specifically without knowing the detail.
Jan, how can you say it “shows the longer term variations underlying the annual, ENSO and PDO cyclic variations”? You don’t know that. You don’t even know how they made the spline. You’re making stuff up again.
Hey and no one read the new Hansen opus 🙂
http://www.columbia.edu/~jeh1/2008/TargetCO2_20080407.pdf
(The link a few posts back works if this one doesn’t)
It’s something you’ll enjoy! Hey Jennifer, you should do a new post about it.
Who’d want to read Heinz Hansen’s unachievable rantings!
Paul, you’d have to be the most intelligent, articulate people I have ever met. Your arguments are so clear and persuasive. I think you are right, yes who would want to read Heinz Hansens unachievable rantings. It’s so clear to me now, AGW is a Global Conspiracy run by Leprechauns…
Mr T, “You don’t know that.”
I have a fair idea I’ve been playing with it but not finished yet. Having said that I can say that I have spent many an hour looking at composite signals often with customers in the process of losing many thousands of dollars per hour looking over the shoulder. Getting the analysis wrong and fiddling about with Fourier Transforms and other assorted filters was simply not an option.
The the temperature waveform is not unlike that of a violin and the spline like the fundamental of the waveform.
I would suggest any EE in a similar position would also say it’s obvious. In any case sticking linear trends in gives rise to discontinuities and that really does violate the laws of nature which abhors discontinuities.
Bazza
The scientific method demands that the models fit the data.
Period.
Pseudoscience demands that when the data fit the model, then that is OK, but when contradictory data are found, then all manner of excuses are offered why the new data are not “proper” or “adequate” or for whatever flimsy excuse that could be mustered.
Mr T
A fit between 3 data points is a linear one, not a spline.
Razor your Occams please.
Paul
I suspect Hansen’s PR is a prelude to Al Gore’s US Presidential aspiration once Hillary Clinton and Barack Obama come to a Mexican position for the Democrat’s nomination for president.
Louis: “A fit between 3 data points is a linear one, not a spline.”
Not exactly a fit between two points is a line a fit between 3 points might be two lines, a curve or a spline the latter usually refers to a piece wise fit using perhaps a number of different polynomials.
The spline in the pic would have required at least 5 points (not 3) and two second order polynomial or one 3 rd order one. These are minimal numbers for that particular spline of course more points and higher orders are possible but could result from over fitting.
Having had a look at the offending plot (it is not a curve, since that is produced by mathematics), the spline curve fit is wrong.
The data seem to show square wave characteristics, or modifications of.
To this geoscientist the breaks in the plot seem important, since any continuous physical process cannot produce these step-like results.
If I looked at that plot from an electrical POV, then the saw tooth pattern would suggest a periodic dielectric failure.
Me: ” a fit between 3 points might be two lines”
should read ” a fit between 3 non-collinear points might be two lines,”
Jen – why not email Graeme Pearman and ask him exactly what he meant?
Jan
All plots are 2D representations, so only one solution is possible.
Louis: “All plots are 2D representations, so only one solution is possible”
I’m not sure what you are on about. You said “A fit between 3 data points is a linear one, not a spline.”
This is not correct mathematically or physically a line is defined by two points if a third point lies on the line good and well. If not then you need either a curve of some sort (includes splines) or you may do a linear regression. Since the time temperature series have orbital factors driving them which gives rise to sinusoids I don’t think a straight line is going to accurately represent them any time soon.
Jan you saved me from Louis! Thanks muchly
And yes, I took a guess about the three point thing, it just looks like the spline hasn’t used many data points.
Mr T, “Jan you saved me from Louis!”
I’m sure you realise that was not my intent. It’s just on this occasion he was IMO less right than you.
Even sawtooth triangular and even squarewaves can according to Fourier theory be built out of adding a series of sinusoids together ( int the cases mentioned they are all harmonics of the fundamental of devreasing amplitude take to infinty). Given that the main drivers of our climate are all rotational or orbital factors it stands to reason that there are many sinusoids making up historical climate data. Removing the noise (cloud movement etc effects) and the short term (ie diurnal, annual, ENSO etc) one by one should reveal eventually a sinusoidal signal relating to the longest term orbital factor. I don’t think that has been reached here but I do think one of the shorter term ones has surfaced – it will take a little/lot more time to check that to my satisfaction at least.
Jennifer,
The thing to keep in mind from Mr. T’s link
“Instead, the team checked the satellite records against ground-based weather station data to inter-calibrate them and make the 26-year satellite record. The scientists estimate the level of uncertainty in the measurements is between 2-3 degrees Celsius”
Who knows how the satellite data was “adjusted” to make this graph.
The data is based on the same data as your picture .
Dave: “Who knows how the satellite data was “adjusted” to make this graph.”
Christy and team area open about how they do things, unlike some others I could mention who change things without telling.
If you wnat to track them you can see the ‘readme’ in the data directory for example:
http://vortex.nsstc.uah.edu/data/msu/t2lt/readme.03Jan2008
There was that saying that “a staticician (protesting if good) could fit a curve through three points, an engineer through two and an eco-fadist through one”
Looking back a couple of threads we could guess this spline curve thingy would turn up again and again. How easily Jennifer tosses it in as a contrast with the Pearman view.
As two other aspects have not been challenged properly, let’s open it up. Lost in space are both steps in temperature trends over the last half a century or so. Also is it fair math to employ anything other than Fourier type analysis with so much rhythmic forcing around?
IMO eliminating any steps is foul play by a would be pure statistician.
Satellite work is not for the naïve and neither is high speed signal analysis. Working back to fundamentals from complex events is still an art not a science.
Sure smoothing the cake with icing provides a fake finish and the candles provide a beacon for its rites of passage. Despite all the decoration I for one am not convinced by the extra layers of icing promoted particularly on these blogs. Icing is for kids. Standing by your nearest monitoring station seems quite beyond our average trooper.
Any one who has sat with a CRO looking for distinguishing features in say a human voice will know where I’m coming from. Yes, vibrations are present as in all music but ask yourself this, what’s your voice look like after its passage over a mobile phone system? Fudge won’t do. Good sampling and filtering techniques are essential in our modern communications.
Let’s add though, patchy data is most bewitching for our come lately non engineering science writers.
Arguments over sparse signals and poor coverage are best paralleled here in the CDMA v TDMA choice some of us had with mobile phones. This war is not over.
http://www.arcx.com/sites/CDMAvsTDMA.htm.
The study of energy distribution goes on and the case for extra wide bandwidth, finding signal energy on the cell fringe etc comes down to our practical experience over time.
http://en.wikipedia.org/wiki/Spread_spectrum
BTW That NASA image can be used for either scenario, warming & cooling
As part of the work undertaken for the Fourth Assessment Report of the IPCC13, about 20 different climate models were run with historical changes to natural and anthropogenic forcing factors to simulate the climate of the 20th century. The simulated changes in Antarctic surface temperatures over the second half of the 20th century vary greatly from model to model with no single model reproducing exactly the observed pattern of change. However, when results from all models are averaged, the resulting pattern of change bears some resemblance to that observed, with greatest warming in the Peninsula region and little change elsewhere. This result suggests that some of the observed change may have an anthropogenic origin, but the lack of a clear and consistent response to changed forcing between models also suggests that much of the observed change in temperatures may be due to natural variability. The IPCC model experiments fail to reproduce some of the observed features, notably the rapid warming of the lower atmosphere. These differences between modelled and observed changes could be used to argue against attributing change to anthropogenic forcing but some caution is called for as the models used may not adequately represent all of the complex processes that determine temperatures in the polar regions.
http://www.antarctica.ac.uk/bas_research/our_views/climate_change.php