From the British Antarctic Survey
New climate history adds to understanding of recent Antarctic Peninsula warming
Results published this week by a team of polar scientists from Britain, Australia and France adds a new dimension to our understanding of Antarctic Peninsula climate change and the likely causes of the break-up of its ice shelves.
The first comprehensive reconstruction of a 15,000 year climate history from an ice core collected from James Ross Island in the Antarctic Peninsula region is reported this week in the journal Nature. The scientists reveal that the rapid warming of this region over the last 100 -years has been unprecedented and came on top of a slower natural climate warming that began around 600 years ago. These centuries of continual warming meant that by the time the unusual recent warming began, the Antarctic Peninsula ice shelves were already poised for the dramatic break-ups observed from the 1990’s onwards.
The Antarctic Peninsula is one of the fastest warming places on Earth – average temperatures from meteorological stations near James Ross Island have risen by nearly 2°C in the past 50 years.
Lead author Dr Robert Mulvaney OBE, from British Antarctic Survey (BAS) says,
“This is a really interesting result. One of the key questions that scientists are attempting to answer is how much of the Earth’s recently observed warming is due to natural climate variation and how much can be attributed to human activity since the industrial revolution. The only way we can do this is by looking back through time when the Earth experienced ice ages and warm periods, and ice cores are a very good method for doing this.”
Dr Mulvaney continues,
“We know that something unusual is happening in the Antarctic Peninsula. To find out more we mounted a scientific expedition to collect an ice core from James Ross Island – on the northernmost tip of the Peninsula. Within the 364m long core are layers of snow that fell every year for the last 50,000 years. Sophisticated chemical analysis – at BAS and the NERC Isotope Geosciences Laboratory (part of British Geological Survey) – was used to re-create a temperature record over this period.
“For this study we looked in detail at the last 15,000 years – from the time when the Earth emerged from the last ice age and entered into the current warm period. What we see in the ice core temperature record is that the Antarctic Peninsula warmed by about 6°C as it emerged from the last ice age. By 11,000 years ago the temperature had risen to about 1.3°C warmer than today’s average and other research indicates that the Antarctic Peninsula ice sheet was shrinking at this time and some of the surrounding ice shelves retreated. The local climate then cooled in two stages, reaching a minimum about 600 years ago. The ice shelves on the northern Antarctic Peninsula expanded during this cooling. Approximately 600 years ago the local temperature started to warm again, followed by a more rapid warming in the last 50-100 years that coincides with present-day disintegration of ice shelves and glacier retreat.”
Co-Author Dr Nerilie Abram formerly from British Antarctic Survey and now with the Research School of Earth Sciences, at The Australian National University says,
“The centuries of ongoing warming have meant that marginal ice shelves on the northern Peninsula were poised for the succession of collapses that we have witnessed over the last two decades. And if this rapid warming that we are now seeing continues, we can expect that ice shelves further south along the Peninsula that have been stable for thousands of years will also become vulnerable.”
Olivier Alemany, from the French Laboratoire de Glaciologie et Géophysique de l’Environnement was part of the expedition. He says,
“The international polar science community has collected and analysed ice cores from Antarctica and Greenland as part of an effort to reconstruct the Earth’s past climate and atmosphere. Our team wanted to understand how the recent warming and the loss of ice shelves compared to the longer term climate trends in the region.”
This research makes a significant contribution to the understanding of the role that Antarctica’s ice sheets play in influencing future climate and sea-level rise. It was funded by NERC (Natural Environment Research Council).
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Regarding that rapid warming of 2C in the last 50 years, just remember that most weather stations in the Antarctic are near humanity, and humanity requires warmth to survive. For example:
The Antarctic peninsula is the most populated place in Antarctica.
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tty says:
August 23, 2012 at 3:29 am
Actually the wind direction is very predictable.
Geoff Alder says:
August 23, 2012 at 3:35 am
and
Marc77 says:
August 23, 2012 at 10:37 am
It is quite clear from both photos that the measurement device is housed within a radiation shield, as is common practice. Anthony took some excellent photos which show how these work (see link). Your points are invalid but there is some irony that a site devoted to disproving AGW (nothing wrong with that of course) keeps blaming humans for the warming.
http://www.skepticalscience.com/WattsandBEST.html
rogerknights says:
August 23, 2012 at 9:29 am
I’ve read that ice cores can’t be used to measure temperatures for the most recent 50, or 100, or 150 years, because the snow hasn’t compacted enough.
——————————————–
The rate of accumulation can be considerable. The P38 “Glacier Girl was recovered from the Greenland ice sheet in 1992 after a force landing in 1942. After 50 years in place it was buried 268 feet below the surface.
http://p38assn.org/glacier-girl-recovery.htm
Don J. Easterbrook says:
August 23, 2012 at 10:59 am
The bottom line here is that this study does NOT show that the Antarctica ice sheet is warming at all.
————————————
This one does.
http://ess.uci.edu/researchgrp/velicogna/files/increasing_rates_of_ice_mass_loss_from_the_greenland__and_antarctic_ice_sheets_revealed_by_grace.pdf
The paper describes an ice loss from the Antarctic ice sheet during 2006 to 2009 of 246Gt/yr, equivalent to a sea level rise of 0.7mm/year.
ScousePete says:
August 23, 2012 at 4:05 am
Well, I got a reply already, and they have indeed now changed it!
Good job Pete! Thanks.
Jeez-Loueez, man.
I had to read that title a couple of times. It my brain hurt made!
Entropic man says:
Don J. Easterbrook says:
August 23, 2012 at 10:59 am
The bottom line here is that this study does NOT show that the Antarctica ice sheet is warming at all.
This one does.
http://ess.uci.edu/researchgrp/velicogna/files/increasing_rates_of_ice_mass_loss_from_the_greenland__and_antarctic_ice_sheets_revealed_by_grace.pdf
The paper describes an ice loss from the Antarctic ice sheet during 2006 to 2009 of 246Gt/yr, equivalent to a sea level rise of 0.7mm/year.
DJE–This study is based entirely on the GRACE (Gravity Recovery and Climate Experiment) data and involves a good deal of statistical computer manipulation and choices. Before accepting the GRACE data, one would like to see how it compares to ground truth, i.e., how does it compare with temperature, snowfall, and other measureable observations in Antarctica and Greenland. For example, just how did this ice loss take place—by melting of ice? The average temperature near the South Pole is about -58ºF and during the winter the temperature often drops below -100 ºF. To get any significant melting, the temperature must warm above 32 ºF for an extended period, requiring a warming of about 100 ºF. Ice can also be lost by sublimation, but this is much less effective than melting and requires substantial warming. Temperatures have been recorded at the South Pole and at Vostock since 1957 and neither station shows any warming trend at all in the past 55 years.
Snowfall is also an important factor, but there is no indication of snowfall reduction. So the question is how is all this ice being lost? All indications are that ice in Antarctica is actually increasing, not decreasing.
And then there is the fact that the GRACE argument for “accelerating ice lost” is only over a three-year period, hardly a significant enough interval to define a trend. Although the GRACE data doesn’t presently seem to be confirmed by actual ground truth, when it can be matched with ground observations, the data may prove to be interesting.
From Nick Kermode on August 23, 2012 at 1:39 pm:
Offhand it appears you don’t understand a Stevenson Screen has louvered sides to keep direct sunlight off the instruments while allowing air flow, is painted white to avoid heating from sunlight… And that the issue discussed is absorption of longwave infrared, which a Stevenson Screen is not designed to prevent. White painted wood objects do warm up from nearby heat sources.
Actually it appears you are aware of this but are deceptively implying that a Stevenson Screen, which protects the instruments from direct solar radiation, will shield them from the longwave radiation, aka radiant heat.
Now you deceptively try to draw innocent readers to a disreputable site with a deceptive article stuffed with misdirection, innuendo, and some outright falsehoods. Google cache here:
Menne 2010 is the disreputable paper using incomplete non-quality controlled data essentially stolen from Anthony and the Surfacestations project. Fall et al 2011 did find the quality of the sites, the siting, did play a role in affecting temperature trends, as discussed in this WUWT post.
Fall et al 2011 has been subsequently superseded by the work in Watts et al 2012, see post here. Using the new WMO-approved siting standards based on Leroy 2010, siting does have a major impact on temperature trends, greatly increasing the warming trends. Since they use the old standards, both Menne and Fall are deprecated.
The deceptive article also does a bait-and-switch, starting with Stevenson Screens then switching to near-IR photos of Gill (multiplate) styled shields for a false “proof”:
First, the pics are meant to illustrate how the temperature sensors are too close to significant heat sources, a violation of siting rules, they are not for scientific assessments of specific temperatures. However, astute readers should notice, as is better seen in the higher quality versions in the original 2009 pdf report: The housings are at different temperatures than their mounting posts. In Figure 8, the “same temperature as nearby land” is seen in the range of temperatures of the heated building, not open land. Figure 10, “same temperature as nearby land” but more than the open air the sensor is supposed to be measuring. Figure 12 is in silhouette thus looks darker (cooler). Figure 14 like Figure 10.
And that shouldn’t apply here as those housings shouldn’t be used in Antarctica. As mentioned in the Abstract of the published paper covered here:
Also, the deceptive article starts by referencing the BEST papers starting with the title, although they are hardly mentioned in the text. No matter, as the BEST papers have failed peer review and been rejected, as noted here.
You also said:
Your accusation is completely false, this site certainly IS NOT DEDICATED to disproving AGW. The scientific research concerning global warming is reviewed here, as well as other things. The usual points of contention are the amount of global warming and what amount of that can be ascribed to anthropogenic causes. There has been no blanket denial of AGW. Indeed, many scholarly articles have appeared here that attempt to quantify the anthropogenic contribution.
You have participated in indirect and direct deception, tried to lure readers to a deceptive article at a disreputable site, and made a blatantly false accusation against this site. Your credibility, and your scruples, are noted.
kadaka (KD Knoebel):
re your post at August 23, 2012 at 11:59 pm. THANKYOU!
I write to draw attention to it because many people ‘skip over’ long posts and your long post is worthy of their attention.
Richard
The article had the following comparison:
“According to the British Antarctic Survey (BAS), ice equivalent to 1,000 years of British domestic water consumption has been lost over the past half century.”
This leads to the previous undefined and highly relevant WTF equivalent [Water to (useless) Factoid].
Don Easterbrook says:
August 23, 2012 at 7:59 pm
“The average temperature near the South Pole is about -58ºF and during the winter the temperature often drops below -100 ºF.
Snowfall is also an important factor, but there is no indication of snowfall reduction. So the question is how is all this ice being lost?
And then there is the fact that the GRACE argument for “accelerating ice lost” is only over a three-year period, hardly a significant enough interval to define a trend.”
The general tone and points raised in your comment suggest limited understanding of how an ice sheet works.
One analogy involves a garden table, wet cement and a bucket. Pour a bucket of cement onto the centre of the table and it slumps into a pile. Add another bucket and the pile becomes higher and wider.As you add more bucketsfull, at some point the pile of cement fills the table and overflows at the edges. Further buckets maintain this shape, but do not change it further.Add a few small stones and visualise how they flow down and out from the centre and off the edge.
Scale things up a bit. The cement is ice, which can flow slowly under pressure.The table is the antarctic bedrock, with the table edge where it meets the ocean.Each Antarctic Winter snow falls on the top of the ice sheet and, once compacted, builds up the surface at about 5 feet/year. The weight of accumulating ice in the centre spreads the ice sheet outwards, At the edge, glaciers flow down off the ice sheet towards the sea. They melt on land when the temperature goes above 0C or form floating ice sheets which melt or break off as icebergs. Note that ice is lost from the ice sheet mostly at the edges, where any extra warming would show as increased flow rates in glaciers and retreating ice sheet edges or glacier calving positions in Summer.
To answer the three points I’ve chosen from your long comment.
Temperatures near the South Pole measure the temperature of the central Antarctic Plateau, some 10,000 ft up and well away from the ocean. Melting very rarely happens there.
Snowfall continues to add ice on the Plateau, which continues to slump. With the Antarctic Plateau isolated from the rest of the planet by its latitude, its altitude and the Polar Vortex I would expect it to be almost literally the last place on Earth to show global warming. Most climate scientists would be surprised to see much change there yet.
I made no mention of acceleration. If you read the paper it does compare the 2006-2009 data with earlier measurements and notes an increase on previous ice loss rates.
Regarding the validity of the GRACE data, I see mutterings about it from the sceptics, but everyone else seems happy. Certainly I’ve seen nothing in the peer-reviewed literature which would invalidate it.
Kakada,
Sorry you took my last comment that way, but in fairness you have misrepresented it and thrown in the D word which is not what I said, nor would say. Anthony and other contributors are certainly dedicated (the word I used) to finding flaws in scientists work (this post as evidence ,as well as recent GISS plotting errors and many others) that might cause a rethink for the majority of climate scientists. That is why I said there is not anything wrong with that, indeed something very important may come from it. I understand people take irony different ways and I apologise if I offended. It was meant to be light hearted.
With regard to your link to to Genthon et al their results are nothing new. Since the early 80’s it has been known that radiation screens vary like that dependant on sun angle and some other variants. Gills own testing showed this. Gill showed that they reach agreement regardless of thermal radiation etc around 10 m/h or maybe less of wind from memory.
Being able to only see the abstract of Genthon I can not tell what they are comparing this fluctuation to. Further problems with that link for this case is that we can’t see if they consider temperature measurement errors as a function of wind speed. The papers that are fully available online that do this experiment find that all tested types of recording devices fall into closer agreement when wind is added and increase their accuracy as the winds increase. If Genthon et al have not done this ( and their caveat of “in the case of low wind speed” suggests they haven’t) their paper and your reference to it is totally irrelevant seeing as they are talking about the Antarctic Plateau which is very calm. This particular commentary is about a the peninsula, a place that averages 50m/h winds year round and records the most extreme winds on the planet. So it would seem (to me) that the research that considers all factors suggests the windier it gets the more accurately the thermometers can consider thermal radiation effects.
We could probably go back and forth all day pointing out each others mistakes and given the fact the actual experts are human they will make some too. We can incredibly accurately measure temperature, that is no doubt, but separating, adjusting, homogenising, biasing,human error, incompetence, problematic technology, problematic terrain and modelling all provide opportunities for us to make mistakes. The fact that what we think are our most reliable sources are pretty much in agreement, and changing all inclusive methods makes little difference, does lend itself to think those involved have it about right.If errors were discovered I certainly wouldn’t be surprised. However a discovery that the results are biased high would give me little comfort and would amount to climate scientists being wrong about the timeframe/rate not the cause. CO2 traps heat, CO2 is released when we burn fossil fuels, CO2 is increasing, heat seeking missiles work, satellites detect less LW radiation at specific CO2 wavelengths leaving the atmosphere, the planet is warming. Disprove some of those and I for one will be incredibly happy but like I originally said a thermometer in the windiest place on earth,upwind of an incredibly well insulated Apple Hut and years after it was first suggested this may cause a bias and to check the numbers is a very long shot indeed. Thanks for your reply, I did learn a few things.
Entropic man–your crude analogy doesn’t answer any of the questions I posed. How is all this supposed ice loss occurring? Where is the evidence of increased melting or increased calving of the main Antarctic ice sheet? Where is the evidence of increasing temperature in the ablation zone? All evidence points to increased thickening of the main ice sheet, not thinning.
You don’t seem to understand that the West Antarctic ice sheet contains only about 10% of Antarctic ice and is surrounded by ocean water that has been warming in recent years. Thus, it is not representative of what is happening with the main Antarctic ice sheet, which shows no indication of accelerating melting. So even if the WAIC is showing signs of ice loss, that says nothing about the overall condition of 90% of Antarctic ice.
Don Easterbrook says:
August 24, 2012 at 7:40 pm
You don’t seem to understand that the West Antarctic ice sheet contains only about 10% of Antarctic ice and is surrounded by ocean water that has been warming in recent years. Thus, it is not representative of what is happening with the main Antarctic ice sheet, which shows no indication of accelerating melting. So even if the WAIC is showing signs of ice loss, that says nothing about the overall condition of 90% of Antarctic ice.
——————————
90% of the Antarctic ice is as it always was. It is piled 3000 metres deep over a continent climatically isolated from the rest of the world and will not be melting in the next few years.. As you say, the effects of waming are showing around the edges, where the ice sheet meets the ocean. The West Antarctic ice sheet is most exposed and showing the most rapid change, the rest of the coastline shows some increase on the Indian ocean side and decrease on the Pacific side, ( http://nsidc.org/icelights/files/2012/01/Antarctic_trends1.png ) but the continental ice sheet damps temperature changes and the overall sea ice anomaly has hardly changed.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.anomaly.antarctic.png
Look at glaciers like Pine Island, and you see faster flows and increased rates of ice loss.
http://ess.uci.edu/~erignot/publications/RignotetalAnnGlaciol34_2002.pdf
NASA measured an increase in snowfall on the East Antarctic ice sheet of about 4.5 gigatonnes/year.
http://www.nasa.gov/pdf/121648main_ais2.pdf
With the GRACE data showing an overall loss of 2.4Gt/yr the amount of annual ice loss from all causes in West Antarctica and around the rest of thecoastline would be about 6.9Gt/yr
Attention Moderators:
Sara says:
August 25, 2012 at 3:23 am
is auto-spam, text grabbed from this comment:
http://wattsupwiththat.com/2012/08/23/antarctic-peninsula-was-1-3c-warmer-than-today-11000-years-ago/#comment-1063650
[thank you . . we normally get these but one does slip through from time to time . . kbmod]
Entropic man says:
August 25, 2012 at 3:57 am
“With the GRACE data showing an overall loss of 2.4Gt/yr the amount of annual ice loss from all causes in West Antarctica and around the rest of thecoastline would be about 6.9Gt/yr”
———————————
I must stop trying to do mental arithmetic when I’m tired.
That last paragraph should have read:-
With the GRACE data showing an overall loss of 246Gt/yr the amount of annual ice loss from all causes in West Antarctica and around the rest of the coastline would be about 250Gt/yr
That human occupation on the Antarctic Peninsula can lead to the calving of massive glaciers, the most obvious consequence of warming there, is somewhat unlikely.
Dear WUWT
I guess I owe the world a humble apology for personally contributing so much to the urban heat island in Antarctica, and hence to misinterpreted climate records.
The badly sited meteorological screen in your photo is at an Australian summer camp in the Northern Prince Charles Mountains, near Mt Jacklyn – in the background. Temperatures measured here were for local information of pilots and field parties only – it is useful to have an idea of how many layers of clothes to put on before exiting your Antarctic shelter. Temperatures here were only measured for less than 2 months over a couple of seasons and have NEVER been used for any climate record.
This photo was taken in the 1988/89 austral summer when I, and a colleague Andy, lived in the UNHEATED shelter nearest to the meteorological station. I didn’t realise that I was so hot that my body heat could influence temperatures measured on the Antarctic Peninsula, thousands of kilometres away. It must have been Andy!!!
Ian
Of course they should also take into account increased clustering of penguins seeking scraps as food. Penguin body heat is an important variable left out of such studies. Similar problems exist in Arctic studies re: polar bear body heat.
Anthony
Correct me if I am wrong here but, as an Australian, I was not aware that Australia had any bases in the Antarctic Penninsular – you know, south of South America and all that. And the photo you show has been identified by Ian as being from a very long way away from the Antarctic Pennisular.
When I mouse over the photo it is labelled as australian_antarctic_postcard.jpg. And it even has a stamp with the ANARE logo on it (Australian National Antarctic Research Expedition).
So what on earth has that photo got to do with a post about the Antarctic Penninsular?
Then when commenters here started trying to dissect the ‘station quality’ issues of this site, you didn’t even mention that the photo has zero to do with the subject of the post. That perhaps going into the detail of how elevated the met station in the photo might be has zero relevence since the station isn’t in the Antarctic Penninsular, isn’t part of any climate record, and only operated few a few months a year as a service to Antarctic pilots.
Did you point this out to any of the commenters here? Why not?
REPLY: It illustrates that weather stations in Antarctica and heat generating/using humanity are in proximity, the same thing happens in the Arctic, such as at the DEW line stations, where they’d “make up temperatures” rather than brave going outside at times.
http://wattsupwiththat.com/2008/07/17/fabricating-temperatures-on-the-dew-line/
Not hard to understand really, people don’t place the weather stations so far away from the huts that they have to risk death to get a reading in subzero temperatures and white out blizzards. – Anthony
And to expand on Rob Painting’s point. Did human occupation of the Antarctic Penninsular lead to the ollapse of the Larsen A & Larsen B ice shelves? Are thet the cause for the retreat of the grounding line of the Pine Island Galcier – admittedly some distance away from the penninsular.
If so how? Lots of dynamite perhaps?
REPLY: First you have to prove that temperature rise measured inland at the Peninsula is manifested in the sea water temperature or above the ice, and show that it in fact made them collapse. Air temperature > water temperature isn’t a strong transfer – Anthony
Anthony, your credibility remains unchanged with me. Keep up the good work!
“….Regarding that rapid warming of 2C in the last 50 years, just remember that most weather stations in the Antarctic are near humanity, and humanity requires warmth to survive….”
So you’re saying that warming in the Antarctic is due to UHI????
Keep it up Anthony, the farce is strong with this one.
REPLY: No dumkopf, there is no UHI since there’s no “urban” in Antarctica. That’s your made up farce. I’m saying that weather stations, like the one shown, are almost always next to human habitation where it is warmer. Really how hard can it be to understand this, especially with a photo?- Anthony
Anthony says:
“How hard can it be to understand this, especially with a photo?”
That photo has been well and truly been proven inadmissible. Can you admit your mistake then provide us some information that proves your point? Cheers
REPLY: It illustrates that weather stations in Antarctica and heat generating/using humanity are in proximity, the same thing happens in the Arctic, such as at the DEW line stations, where they’d “make up temperatures” rather than brave going outside at times.
http://wattsupwiththat.com/2008/07/17/fabricating-temperatures-on-the-dew-line/
Not hard to understand really, people don’t place the weather stations so far away from the huts that they have to risk death to get a reading in subzero temperatures and white out blizzards. – Anthony
[Snip. Try to be deferential to our host. Use a “/sarc” tag if you’re trying to be funny. ~dbs, mod.]
With all due respect, how can a building have an effect on a temperature trend if the building is the same distance from the thermometer, year after year?