From a press release provided by Centre national de la recherche scientifique in Paris, France:
Improved estimate of glacier decline in Alaska.
Glaciologists at the Laboratory for Space Studies in Geophysics and Oceanography (LEGOS – CNRS/CNES/IRD/Université Toulouse 3) and their US and Canadian colleagues (1) have shown that previous studies have largely overestimated mass loss from Alaskan glaciers over the past 40 years. Recent data from the SPOT 5 and ASTER satellites have enabled researchers to extensively map mass loss in these glaciers, which contributed 0.12 mm/year to sea-level rise between 1962 and 2006, rather than 0.17 mm/year as previously estimated.
Mountain glaciers cover between 500 000 and 600 000 km2 of the Earth’s surface (around the size of France), which is little compared to the area of the Greenland (1.6 million km2) and Antarctic (12.3 million km2) ice sheets. Despite their small size, mountain glaciers have played a major role in recent sea-level rise due to their rapid melting in response to global climate warming.
Of all the ice-covered regions of the planet, ice loss has been the greatest in Alaska and northwestern Canada, where glaciers cover 90 000 km2. Results from the LEGOS glaciologists and their US and Canadian colleagues, published in the February issue of Nature Geoscience, lead them to conclude that these glaciers have contributed 0.12 mm/year to sea-level rise over the period 1962-2006, rather than 0.17 mm/year as previously estimated by a team at the Geophysical Institute at the University of Alaska (Fairbanks). The new estimate was obtained by comparing recent topographies, derived from Spot 5-HRS (SPIRIT project (2) funded by CNES) and ASTER (GLIMS/NASA project), with maps from the 1950-60s, which enabled loss from three quarters of the Alaskan glaciers to be measured.
How did the team from the Geophysical Institute of the University of Alaska estimate that the contribution of these glaciers to sea-level rise was 0.17 mm/year? In 1995, and then again in 2001, the researchers used an airborne laser to measure the surface elevation of 67 glaciers along longitudinal profiles. These elevations were then compared with those mapped in the 1950s and 1960s. From this, the researchers inferred elevation changes and then extrapolated this to other glaciers. Their results, published in Science (3), pointed to a major contribution to sea-level rise for the 1950-1995 period (0.14 mm/year sea-level rise), which then doubled in the recent period (after 1995).
Why did they overestimate ice loss from these glaciers by 50%? The impact of rock debris that covers certain glacier tongues (4) and protects them from solar radiation (and thus from melting) was not taken into account in the previous work. Moreover, their sampling was limited to longitudinal profiles along the center of a few glaciers, which geometrically led to overestimation of ice loss.
This new study confirms that the thinning of Alaskan glaciers is very uneven, and shows that it is difficult to sample such complex spatial variability on the basis of a few field measurements or altimetry profiles. Thanks to their regional coverage, satellite data make it possible to improve observations of glacial response to climate change and to specify the contribution of glaciers to sea-level rise.
Ice loss from Alaskan glaciers since1962 is evidently smaller than previously thought. However, thinning (sometimes over 10 m/year, as in the Columbia glacier) and glacial retreat remain considerable. Moreover, the spectacular acceleration in mass loss since the mid 1990s, corresponding to a contribution of 0.25 to 0.30 mm/year to sea-level rise, is not in question and proves to be a worrying indication of future sea-level rise.
NOTES:
(1) from Northern Arizona University (US) and two universities in Canada (University of British Columbia and University of Northern British Columbia).
(2) During the 4th International Polar Year (2007-2009), the glaciologists had free access to SPOT 5-HRS data thanks to the SPIRIT project (SPOT 5 stereoscopic survey of Polar Ice: Reference Images and Topographies). The high-resolution images from this satellite can be used to reconstruct precisely the topography of polar ice and thus study its past and future evolution in response to climate fluctuations. LEGOS is the scientific coordinator for this project, which was carried out with CNES, Spot Image and IGN Espace.
(3) Arendt et al, Rapid wastage of Alaska glaciers and their contribution to rising sea level. Science 297, 382-386 (2002)
(4) The lower parts of a valley glacier.
References:
Berthier E., Schiefer E., Clarke G.K.C., Menounos B. & Remy, F. Contribution of Alaskan glaciers to sea level rise derived from satellite imagery. Nature Geoscience, 3(2), 92-95, doi: 10.1038/ngeo737, 2010
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That’s not true! The Glaciers in Alaska have all melted, All we are left with now is (yes, you guessed it) “rotten” ice….
After the Copenhagen failure, some scientists crawled from their holes and started publishing slightly more realistic stuff..
I am waiting for the 2009 Swiss glaciers update, which is already 1 month late
http://glaciology.ethz.ch/messnetz/lengthvariation.html
I think 2009 will be similar to 2008 though.
“[I]nferred elevation changes and then extrapolated this to other glaciers” – that doesn’t sound like the original “calculation” was much more than a wild guess to make it into the press. Anyway, I’m glad the glaciers are still retreating from the last ice age and I see the obligatory “global climate warming” has made it into this article.
Here’s a great report/interview on the sea level hoax;
http://www.climatechangefacts.info/ClimateChangeDocuments/NilsAxelMornerinterview.pdf
It’s great that the data is getting better. The underestimation was no “conspiracy” but simply incomplete data. To really put this whole article into perspective in terms of how it might relate to AGW, just go to the final summary statement:
Moreover, the spectacular acceleration in mass loss since the mid 1990s, corresponding to a contribution of 0.25 to 0.30 mm/year to sea-level rise, is not in question and proves to be a worrying indication of future sea-level rise.
Bottom line, just as we saw with the Himlayan glacier melt fiasco, the direction isn’t being questioned…just the intensity.
0.12mm or 0.17mm per year of sea level rise has some people worried?
You need to 97,000 cubic miles of ice to raise sea levels by 1 meter.
97 cubic miles will give you 1mm of sea level rise.
I’m impressed the satellites can record a change of 11.64 cubic miles
of ice melt over a period of one year.
Do people recognize that these magnitudes are not much larger than the thickness of a human hair? They matter not at all in the context of 5 or so meters of surge from a storm. Moreover, we do not calculate what effects imbalances in the flow of groundwater into the oceans, nor imbalances in river in-flow, are versus net evaporation. Consequently how can we speak at all about cause and effect?
There’s some information that I missed the other day in the report on the UAH January global-average lower tropospheric temperature anomaly that I read on another blog:
0.72 is the highest Jan anomaly in the data, beating 0.59 in Jan 07 and 0.58 in Jan 98. That’s an improvement of 0.13 deg. C.
And some more info to put things in perspective:
“The UAH anomaly hit 0.50 last November, the highest Nov anomaly in the records. The runner-up was Nov ‘05 with 0.40 and only two other Nov anomalies exceeded 0.30.
And the September UAH anomaly hit 0.42, the second highest for that month. The record was Sep ‘98 with 0.43, and only other September reading to exceed 0.30 was Sep ‘05 with 0.35.
And the July UAH anomaly was also 0.42, the second highest in the record. The record was Jul ‘98 with 0.52, with the third place going to Jul ‘05 with 0.33. Only one other July exceeded 0.30.”
AFAIK, the Pacific isn’t experiencing the Super El Niño it did in 1998, the PDO is in its negative phase and the sun is still not very active at the moment. Remarkable.
…lead them to conclude that these glaciers have contributed 0.12 mm/year to sea-level rise over the period 1962-2006, rather than 0.17 mm/year as previously estimated by a team at the Geophysical Institute at the University of Alaska (Fairbanks).
Then at the end of the article…
Moreover, the spectacular acceleration in mass loss since the mid 1990s, corresponding to a contribution of 0.25 to 0.30 mm/year to sea-level rise, is not in question and proves to be a worrying indication of future sea-level rise.
Since the mid-1990’s the rate has been doubled what it was for a period that includes the doubled rate? The rate from 1962 to the mid-1990’s must have been very small. How good were the old maps they used to figure it?
Of course, when looking at the data, an obvious conclusion can be drawn. Making Alaska a state in 1958 accelerated the glacier melting. It was never this bad before statehood.
“This new study confirms that the thinning of Alaskan glaciers is very uneven, and shows that it is difficult to sample such complex spatial variability on the basis of a few field measurements or altimetry profiles. Thanks to their regional coverage, satellite data make it possible to improve observations of glacial response to climate change and to specify the contribution of glaciers to sea-level rise.”
If the glaciers are so difficult to map how can we rely on the 1950 mappings?
“This new study confirms that the thinning of Alaskan glaciers is very uneven, and shows that it is difficult to sample such complex spatial variability on the basis of a few field measurements or altimetry profiles.”
Makes me wonder about the GISS samples of complex temperature spatial variability.
Comedy Central Data Team is at it again.
They must have left some salt water in their graduates from the last test.
This gets better and better.
The CCDT needs to start serving popcorn with their shoes.
Sorry, but I am not buying the B.S. – no way they can measure (or determine all of the inputs into supposed sea-level rise).
The new study is an update. However, it compares a different period of years and includes different glaciers and comes to a similar conclusion as the 1950-1995 study determined. 0.12 mm/a versus 0.14 mm/a. Not a significant difference. The 0.17 mm for a different time period is hardly a significant difference. At this point it cannot be determined whether both studies are accurate, or which may be more accurate, but the results belie the headline. This is not a large change. The mass balance of alaskan glaciers is always changing so the same span of years must be used for direct comparison. Note the mass balance record for Lemon Creek Glacier, the second longest record in Alaska
http://www.nichols.edu/departments/Glacier/Lemon.html
and note the changes in Gilkey Glacier
http://glacierchange.wordpress.com/2009/11/01/215/
Pretty desperate stuff on the front page of the Independent on Sunday.
http://www.independent.co.uk/environment/climate-change/thinktanks-take-oil-money-and-use-it-to-fund-climate-deniers-1891747.html
The article is complete rubbish from start to finish and the online comments it has had are pretty scathing, and rightly so. I cannot imagine why anyone would think this nonsense was worth publishing.
The solution to any sea level rise problems is to move if you are about to be inundated.
“Neven (11:24:37) :
[…]
0.72 is the highest Jan anomaly in the data, beating 0.59 in Jan 07 and 0.58 in Jan 98. That’s an improvement of 0.13 deg. C.”
Sounds pretty impressive. We should see some serious water vapour feedback now.
‘Moreover, the spectacular acceleration in mass loss since the mid 1990s, corresponding to a contribution of 0.25 to 0.30 mm/year to sea-level rise, is not in question and proves to be a worrying indication of future sea-level rise.’
Wouldn’t a scientific report just say:
‘Moreover, the mass loss since the mid 1990s, corresponding to a contribution of 0.25 to 0.30 mm/year to sea-level rise, is not in question.’
Sounds like the conclusion has been pre-written for the IPCC.
R. Gates (11:05:42) :
It’s great that the data is getting better. The underestimation was no “conspiracy” but simply incomplete data. To really put this whole article into perspective in terms of how it might relate to AGW, just go to the final summary statement:
Moreover, the spectacular acceleration in mass loss since the mid 1990s, corresponding to a contribution of 0.25 to 0.30 mm/year to sea-level rise, is not in question and proves to be a worrying indication of future sea-level rise.
Bottom line, just as we saw with the Himlayan glacier melt fiasco, the direction isn’t being questioned…just the intensity.
========
what is being questioned, is the “link” to co2.
not climate variability.
Is there anything left that hasn’t been fabricated, exaggerated, or flat out made up?
SPOT-5 Satellite Launch Date: May 3, 2002
ASTER Satellite System: Launch Date 18 December 1999
“Recent data from the SPOT 5 and ASTER satellites have enabled researchers to extensively map mass loss in these glaciers”
“Moreover, the spectacular acceleration in mass loss since the mid 1990s, corresponding to a contribution of 0.25 to 0.30 mm/year”
… This seems to be an interesting conclusion to draw from observations that weren’t being made at the time !
Neven,
I notice that August, October, and December somehow did not make your list of ALARMING temps!!! Why is that??
If your ALARMING temps are so ALARMING, how did these other months not even manage to be much above average?? Darn, you apparently MISSED something in compiling your ALARMING statistics!!! Wonder what this freezing February will be?? Wonder why the Arctic ice isn’t significantly lower than recent years if things are so HOT!!!
Hmmm, UAH switched to a different satellite sometime last year. Maybe you could check and find out when??
With all due respect to the hard work of Dr. Spencer and the rest of the UAH crew, remote sensing is highly statistics based and, occasionally, mistakes are made in the calibration. Amazingly enough, almost always corrected to the high side!!
You ever think about those adjustments meant to correct for the atmospheric conditions between the sensor in orbit and the band of atmosphere below a lot of other atmosphere?? They must be based on how historic atmospheric conditions have affected the sensing. What if there is something different, if only slightly, in the conditions in the atmosphere between that band and the sensor?? You think they will get a true reading??
What are the odds … the slow drip – drip of the IPCC’s loss of credibility owing to recently aired stories, the slow drip – drip of the UEA’s loss of credibility due to revelations in The sCRUtape Letters which also have contributed to the erosion of ‘climate science’ in general … have we seen the tide take a bit of a turn, is it possible now for scientists with more questions than answers to question AGW doctrine, openly and in public, to challenge the accepted precepts which are used and abused to support the ‘theory’ of Anthopogenic (carbon-based humanoid caused) Global Warming (AGW)?
Published works like this cause me to think so.
.
.
Mike J (11:35:03) :
If the glaciers are so difficult to map how can we rely on the 1950 mappings?
There is really not much to say about where we are going if we don’t have high confidence in where we have been.
Which is a fancy way of saying we can’t.
Climategate professor starts boo-hooing
From Britain’s Sunday Times
Not sure if that’s actually possible, but reading on…
Wonder if he was so candid on his job application?
Sorry, Phil – it’s called the law of the land.
He’s playing for sympathy – but the commenters take no prisoners…
The Arctic Climate Impact Assessment (ACIA) includes this proviso:-
2.6.2.1 There is still need for further study before it can be firmly concluded that the increase in arctic temperatures over the past century and/or past few decades is due to anthropogenic forcing.
However, the Executive Summary of ACIA gives no such proviso, stating that for global climate “human influences have now become the dominant factor” and “These climate changes are being experienced particularly intensely in the Arctic”
http://amap.no/acia/
ACIA is about ready for a detailed audit.