From EurekAlert
International Greenland ice coring effort sets new drilling record in 2009
Ancient ice cores expected to help scientists assess risks of abrupt climate change in future
 |
||||
 |
 |
|
 |
|
|
 |
  IMAGE: Atmospheric gases trapped in ancient ice recovered during the international North Greenland Eemian Ice Drilling, or NEEM, project are expected to help scientists better assess the risks of abrupt climate…
|
|
|
|
 |
|
 |
|
|
||||
A new international research effort on the Greenland ice sheet with the University of Colorado at Boulder as the lead U.S. institution set a record for single-season deep ice-core drilling this summer, recovering more than a mile of ice core that is expected to help scientists better assess the risks of abrupt climate change in the future.
The project, known as the North Greenland Eemian Ice Drilling, or NEEM, is being undertaken by 14 nations and is led by the University of Copenhagen. The goal is to retrieve ice from the last interglacial episode known as the Eemian Period that ended about 120,000 years ago. The period was warmer than today, with less ice in Greenland and 15-foot higher sea levels than present — conditions similar to those Earth faces as it warms in the coming century and beyond, said CU-Boulder Professor Jim White, who is leading the U.S. research contingent.
While three previous Greenland ice cores drilled in the past 20 years covered the last ice age and the period of warming to the present, the deeper ice layers representing the warm Eemian and the period of transition to the ice age were compressed and folded, making them difficult to interpret, said White. Radar measurements taken through the ice sheet from above the NEEM site indicate the Eemian ice layers below are thicker, more intact and likely contain more accurate, specific information, he said.
“Every time we drill a new ice core, we learn a lot more about how Earth’s climate functions,” said White, “The Eemian period is the best analog we have for future warming on Earth.”
Annual ice layers formed over millennia in Greenland by compressed snow reveal information on past temperatures and precipitation levels and the contents of ancient atmospheres, said White, who directs CU-Boulder’s Institute of Arctic and Alpine Research. Ice cores exhumed during previous drilling efforts revealed abrupt temperature spikes of more than 20 degrees Fahrenheit in just 50 years in the Northern Hemisphere.
The NEEM team reached a depth of 5,767 feet in early August, where ice layers date to 38,500 years ago during a cold glacial period preceding the present interglacial, or warm period. The team hopes to hit bedrock at 8,350 feet at the end of next summer, reaching ice deposited during the warm Eemian period that lasted from roughly 130,000 to 120,000 years ago before the planet began to cool and ice up once again.
The NEEM project began in 2008 with the construction of a state-of-the-art facility, including a large dome, the drilling rig for extracting 3-inch-diameter ice cores, drilling trenches, laboratories and living quarters. The official drilling started in June of this year. The United States is leading the laboratory analysis of atmospheric gases trapped in bubbles within the NEEM ice cores, including greenhouse gases like carbon dioxide and methane, said White.
The NEEM project is led by the University of Copenhagen’s Centre of Ice and Climate directed by Professor Dorthe Dahl-Jensen. The United States and Denmark are the two leading partners in the project. The U.S. effort is funded by the National Science Foundation’s Office of Polar Programs.
“Evidence from ancient ice cores tell us that when greenhouse gases increase in the atmosphere, the climate warms,” said White. “And when the climate warms, ice sheets melt and sea levels rise. If we see comparable rises in sea level in the future like we have seen in the ice-core record, we can pretty much say good-bye to American coastal cities like Miami, Houston, Norfolk, New Orleans and Oakland.”
Increased warming on Earth also has a host of other potentially deleterious effects, including changes in ecosystems, wildlife extinctions, the growing spread of disease, potentially catastrophic heat waves and increases in severe weather events, according to scientists.
While ice cores pinpoint abrupt climate change events as Earth has passed in and out of glacial periods, the warming trend during the present interglacial period is caused primarily by human activities like fossil fuel burning, White said. “What makes this warming trend fundamentally different from past warming events is that this one is driven by human activity and involves human responsibility, morals and ethics.”
Other nations involved in the project include the United States, Belgium, Canada, China, France, Germany, Iceland, Japan, Korea, the Netherlands, Sweden, Switzerland and the United Kingdom.
Other CU-Boulder participants in the NEEM effort include INSTAAR postdoctoral researcher Vasilii Petrenko and Environmental Studies Program doctoral student Tyler Jones. Other U.S. institutions collaborating in the international NEEM effort include Oregon State University, Penn State, the University of California, San Diego and Dartmouth College.
For more information on the NEEM project, including images and video, visit http://www.neem.ku.dk.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Sorry, I also made a simple shortcut math mistake.
Hansen’s forcing numbers work out to be 288K, which is today’s temperature, not the ice age temperature which is supposed to be around 283K.
So, not only does his averages not work out to the proper Solar Forcing numbers and the proper Greenhouse Forcing numbers, he actually doesn’t simulate an ice age at all – he simulates today’s temperatures.
Bill Illis says:
I agree that this argument is wrong. But, could you please show me where Hansen has made this argument? I don’t know of anybody who assumes the 0.75 C / [W/m^2] holds over the whole scale all the way down to absolute zero.
Just because you can come up with a silly argument that miraculously reproduces the Hansen’s result does not mean that Hansen’s arguments or conclusions are incorrect…It just means that your argument is incorrect.
By the way, Bill, you are of course never going to come up with 0.75 C / [W/m^2] using the Stefan-Boltzmann Equations since these equations will give you only the “bare” response in ABSENCE of feedbacks (which is somewhere around 0.25-0.3 C / [W/m^2], as I recall, when the calculation is done correctly).
The 0.75 C / [W/m^2] result is what Hansen estimates in the presence of (relatively fast) feedbacks…and it is obtained simply from the empirical observations of what the temperature difference was during the LGM along with estimates of what the forcings were. I imagine that one could conceivably make arguments that Hansen hasn’t estimated these forcings well. However, you haven’t made any here that don’t seem to rely on incorrect assumptions about how you think Hansen might have estimated them.
However, you haven’t made any here that don’t seem to rely on incorrect assumptions about how you think Hansen might have estimated them.
Huh????
soph·is·try (sf-str)
n. pl. soph·is·tries
1. Plausible but fallacious argumentation.
2. A plausible but misleading or fallacious argument.
The American Heritage® Dictionary of the English Language, Fourth Edition
Joel Shore (19:33:35) : “I imagine that one could conceivably make arguments that Hansen hasn’t estimated these forcings well.”
Yeah, for good reasons.
Legally insane people can not sign contracts….why should they be relied upon for scientific information?
Chris
Norfolk, VA, USA
Joel Shore (19:33:35) :
“I imagine that one could conceivably make arguments that Hansen hasn’t estimated these forcings well. However, you haven’t made any here …”
I am just testing out some parts of a post I am working on – trying to see if there are valid arguments against it.
So, let’s say I have calculated that the Albedo of the Earth during the last glacial maximum was about 0.333 (versus today of 0.298).
Solar forcing at the surface would therefore have changed by -12.0 watts/metre^2 (versus Hansen’s -3.5).
= [1366 watts^m^2 * (1-0.333)/4] – [1366 watts^m2 (1-0.298)/4 = -12.0 watts/m^2
So yeah, I am saying Hansen’s -3.5 watts^2 is a very bad estimation. To get that kind of number you’d have to assume there was no change in Albedo beyond 60 degrees latitude or the southern tip of Greenland (ie. no glaciers in Churchill Canada, Chicago, New York, Scotland or Moscow and no sea ice at Newfoundland, or any increase in sea ice around Antarctica).
In the last ice-age I presume that the southern ice-cap joined to South America. Surely this would have blocked the circum-polar current and done weird things to the Humboldt current and El Nino?
TonyB – Thanks . This is what I get for checking back on old posts .
Sandy (08:08:56)
The reconstructions do not show sea ice extending through the Drake Passage to South America. There is a moderate increase around the rest of Antarctica and glaciers would have pushed past the coast but at the Drake Passage, there is enough biologic evidence to show there wasn’t sea ice here (probably ocean currents and winds kept it ice-free).
Of course, on South America, glaciers built up on the Andes so the Drake Passage would have had mile-high glaciers on both sides.
TonyB – OK , I read it or , rather , slogged through it . As a layman , I’m not sure how he reached some of his conclusions but I wish I had ten bucks for every time he used the word assume . Also , Is tortuosity really a word ?
“”” savethesharks (20:27:42) :
However, you haven’t made any here that don’t seem to rely on incorrect assumptions about how you think Hansen might have estimated them.
Huh????
soph·is·try (sf-str)
n. pl. soph·is·tries
1. Plausible but fallacious argumentation.
2. A plausible but misleading or fallacious argument. “””
Which leads one to the observation that people who think they are sophisticated, often truly are !
“”” S.E.Hendriksen (15:55:28) :
We actually have all the data from the Eem-time from the DYE 3 drilling… do they try to confirm themself or what?
It was 5-6 degrees warmer in Grenland on that time a the Ice cap was intact far away South of DYE 3 (according to the drilling data)….but we don’t no much about the edge melting.
KInd regards
Svend “””
Good to see a post from you Svend; nothing like getting the scoop right from ground zero.
Are you going to help them drive stakes into the ice to pin it down this winter so it doesn’t all fall off; or are you going home to the mainland to wait it out.
Do keep us posted on what these folks are up to with this new ice core. My prediction is that you do not have to worry about having no ice on Greenland any time soon.
Cheers.
George
P Walker
You have learnt your lessons well grasshopper…The words ‘assumed’ ‘modelled’ or ‘interpolated’ will get you far in the settled world of climate science.
Ice core methodology pushes the boundarie of my credulity too far, I much prefer the actual readings unearthed by Ernst Beck. If you have not already done so a visit to his site is well worth while.
tony b
This has grated with me since I first read it a couple of days back!
Have we ever seen sea level rises in the ice core record?
DaveE.
TonyB – don’t know if you’re still checking this post , but I have one of Beck’s papers on file . I tried to enter another , more succinct one , but it didn’t go . I also found a paper bt Jaworski (Jakowski ? ) thae ripped ice core methodology , particularily in regard to extraction .
Bill Illis says:
Well fine, but how did you get that estimate for the change in albedo? Are you properly accounting for issues such as the less solar radiation per unit surface area (due to obliquity) in the high latitudes as opposed to the low latitudes…and the fact that ice underneath dense cloud cover will not significantly change the albedo?
You are making grand statements about how Hansen is wrong while providing no evidence to back them up.
Bill:
By the way, a little bit of google searching turned up this paper http://www.springerlink.com/content/657k8yf6e6ml5c8y/fulltext.pdf which may be a useful source into the literature on modeling the LGM vs the current climate. (You can also use google scholar to find 6 more recent papers that cite it: http://scholar.google.com/scholar?cites=13237043494166736609&hl=en ) Interestingly (if I understand it correctly from a quick skim), this paper seems to conclude that more the temperature change was caused by CO2 than by the icesheet+other albedo effects, which implies even less role for ice sheet albedo changes than Hansen assumes.
Joel Shore (16:44:21) :
“Are you properly accounting for issues such as the less solar radiation per unit surface area (due to obliquity) in the high latitudes as opposed to the low latitudes…”
The area between 40N-50N is 6.2% of the surface area of the Earth and receives 89.2% of the average solar radiation … so that is all accounted for properly.
“… and the fact that ice underneath dense cloud cover will not significantly change the albedo? ”
Clouds are definitely an issue but the climate models can’t simulate clouds or cloud cover properly so there is no reason to believe the climate models can do this any better than assuming there is no change in the average cloudiness of the Earth.
If one wanted to make the argument that cloud cover decreases (lowering the Albedo) during an ice age then one is dangerously close to accepting Lindzen’s “Iris” proposition which the climate science community has soundly rejected. If cloudiness increases during an ice age, then we have vastly understated the Albedo increase.
We do have an increase in continental glaciation which should increase the cloud cover on the margins of the glaciers. There is also an increase in desert conditions (and much more grassland due to the lower CO2) so that should lead to less cloud cover over these regions etc. etc. The increased dust levels in the ice cores do not neccessarily indicate that it was dryer since the biggest increase in dust levels happens during the periods when the glaciers were melting back (probably the loess left behind when the glaciers stop moving forward and melt back).
But nobody should ever mention the positive ice-albedo-feedback due to global warming again if the same researchers nearly completely discount the effect for the massive increase in snow and ice during the ice ages.
I just cannot accept the climate model simulations since all the impacts just seem so schizophrenic like the above points indicate. (Albedo only matters when it is a positive temperature impact – clouds only matter when they point to high CO2 sensitivity – a mile of ice on 20 million km^2 of land and an increase in 20 million km^2 in sea ice has almost no impact on Albedo – we use the Stefan Boltzmann equations to set all the parametres and formulae for the greenhouse effect but we don’t use it all in climate models or when the Albedo changes – etc. …)