Ice cores yield rich history of climate change

Feb 02, 2011
A researcher inspects a freshly-drilled ice core. Credit: Kendrick Taylor, Chief Scientist, WAIS Divide Ice Core Project Research Professor, Desert Research Institute, Nevada System of Higher Education

On Friday, Jan. 28 in Antarctica, a research team investigating the last 100,000 years of Earth's climate history reached an important milestone completing the main ice core to a depth of 3,331 meters (10,928 feet) at West Antarctic Ice Sheet Divide (WAIS). The project will be completed over the next two years with some additional coring and borehole logging to obtain additional information and samples of the ice for the study of the climate record contained in the core.

As part of the project, begun six years ago, the team, funded by the National Science Foundation (NSF), has been drilling deep into the ice at the WAIS Divide site and recovering and analyzing ice cores for clues about how changes in the concentration of greenhouse gases in the atmosphere have influenced the Earth's climate over time.

Friday's milestone was reached at a depth of 3,331 meters--about two miles deep--creating the deepest ice core ever drilled by the U.S. and the second deepest ice core ever drilled by any group, second only to the ice core drilled at Russia's Vostok Station as part of a joint French/U.S./Russian collaboration in the 1990s.

"By improving our understanding of how natural changes in influenced climate in the past, the science community will be able to do a better job of predicting future climate changes caused by the emissions of greenhouse gases by human activity," said Kendrick Taylor, chief scientist for the WAIS Divide Ice Core Project.

The drilling site is about 966 kilometers (600 miles) from the , at an ice divide (which is analogous to a watershed divide) in West Antarctica, where the ice is flowing out to the sea in opposing directions.

"This location was selected because it is the best place on the planet to determine how greenhouse gases have changed during the last 100,000 years" said Taylor. Since it began, the WAIS Divide Ice Core Project has continuously collected ice from the surface down to a depth of 3,331 meters. The ice at this depth fell as snow about 100,000 years ago. The high annual snowfall at the site enables individual annual layers of snowfall to be identified and counted (much like counting tree rings) back to about 40,000 years. Below that, the layers become too compressed to allow annual layers to be resolved. Scientists hope for at least decadal resolution to this point, sufficient for the science goals to be achieved.

The ice cores are 13-centimeter (5-inch) diameter cylinders of ice collected from deep in the ice sheet. Over time, the ice has formed when snow was compacted at the surface by subsequent snowfall. The compacted snow contains dust, chemicals and atmospheric gases, which are trapped in the ice.

A researcher examines layers in a snow pit deposited by different storms. Credit: Kendrick Taylor, Chief Scientist, WAIS Divide Ice Core Project Research Professor, Desert Research Institute, Nevada System of Higher Education

The dust and other impurities in the ice are indicators of past climate, and the gas contained in air bubbles is a sample of the ancient atmosphere. The deeper the ice, the further back in time measurements can be made.

In addition to measuring what the atmospheric concentrations of , methane and other gases were in the past, the research team can also determine what the surface air temperature was in the past by studying changes in the isotopic composition of the water that makes up the ice. The past atmospheric concentrations of the gases krypton and xenon are used to determine what the average temperature of the ocean was in the past.

The 13-centimeter diameter 3,331-meter-long ice core is cut into 1 meter (3 feet)-long pieces of ice and sent by ship and refrigerated truck to the NSF National Ice Core Laboratory in Denver. The ice is cut into smaller samples and sent to 27 investigators around the U.S., who make the measurements.

"Previous ice cores have shown that the current level of greenhouse gases is greater now than at any time during the last 650,000 years, and that concentrations today are increasing at the fastest rate," said Taylor. "This increase is caused by human activity and is forcing the climate into a configuration that no human has ever experienced."

This is a section of an ice core coming out of the drill. Credit: Mark Twickler, University of New Hampshire

The WAIS Divide Ice Core Project is specifically investigating the small timing offsets between past changes in the atmospheric concentration of greenhouse gases and changes in temperature. By understanding these timing offsets, the research team can determine the role that changes in ocean circulation had in the release of carbon dioxide from the ocean and how an increase in carbon dioxide in the atmosphere warms the planet.

The drilling ceased 100 meters (328 feet) above the contact between the ice and the underlying rock, to avoid contaminating a possible water layer at the ice-rock contact. The basal water system may consist of water-saturated, ground-up rock, and has not been exposed to the earth's surface for millions of years. It may harbor a unique and pristine biological environment that the U.S. Antarctic Program does not wish to contaminate.

The core taken by the WAIS Ice Core Drilling Project is crucial for fine-tuning the researchers' understanding of how the oceans, atmosphere and climate interact during climate changes. A Danish-led team recovered an ice core from Greenland this past summer with similar time resolution to the WAIS Divide record. The two cores provide an opportunity to compare the response of the northern and southern hemispheres to climate changes. The Greenland ice core cannot be used to study changes in the atmospheric concentration of carbon dioxide because there is too much dust in the Greenland ice, which decomposes and releases non-atmospheric carbon dioxide into the ice.

NSF's Office of Polar Programs funds this research, primarily through its Antarctic Glaciology Program.

"We still have two more field seasons of work to complete the project, and reaching this goal should allow us to complete the project on schedule," said Julie Palais, program director. "In addition, we are hoping to get as long a record as possible from this site, and getting all of the ice we planned on this year will allow the science community to do the work that they are funded to do. Drilling the is just the first step in the process, albeit a very important one."

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User comments : 37

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3432682
2.4 / 5 (25) Feb 02, 2011
Gotta sneak in "climate change" don't you? It's just history of climate.
Skeptic_Heretic
3.2 / 5 (22) Feb 02, 2011
Gotta sneak in "climate change" don't you? It's just history of climate.

And according to you specifically, what is the history of climate? That's right, change. You seem to have a problem with two words being strung together. I'd suggest you examine that irrational response.
rgwalther
1 / 5 (1) Feb 02, 2011
Or respond to that irrational examination.
Canux
5 / 5 (3) Feb 02, 2011
I have a question about this sort of thing if someone here who knows more about this subject than I do could enlighten me. I was listening to a report on the BBC recently about this and they described "air bubbles" in the ice that were used to determine the amount of carbon dioxide in the air when the ice was formed. In the report you could hear the bubbles popping as the ice warmed because the bubbles had been under such pressure.

My immediate thought was "What about ablation?" (description of ablation deleted as I went way over comment length limit)

What I am asking is effectively "would the contents of an air bubble inserted into a block of ice and then left frozen for 100,000 years be chemically altered by its surroundings?" And if so, do these studies account for this mathematically?

Any insight would be appreciated.
Arkaleus
2.9 / 5 (13) Feb 02, 2011
What is "Normal" climate? What is "abnormal" climate? What is the absolute standard you are comparing it to? Warm climate may be better for human civilization than cold, modern post-ice age climate. I welcome a return to warmer times, maybe even as warm as the middle ages were for the northern countries.

The arbitrary assignment of abnormal to any current climate description is nonsensical and fails to capture the scope of climate change that has occurred on the planet, whatever their causes. The BEST climate for life on this planet is certainly much warmer, simply look back on the fossil record to see what the climate was like when there was the most life in the most regions of the world.
Skeptic_Heretic
3.7 / 5 (10) Feb 02, 2011
My immediate thought was "What about ablation?" (description of ablation deleted as I went way over comment length limit)
How would ablation have anything to do with a core sample? Ablation is a surface phenominon. These air bubbles are far from an exposed surface. The internal pressure of the gasses is due to compaction due to the weight of the layers above. If it wasn't exposed to chemical elements in the ice prior to sequestration, then those chemical elements wouldn't be present in the sample without leaving an obvious signature.
GSwift7
3.9 / 5 (7) Feb 02, 2011
@ Canux:

You're on the right track, but ablation isn't exactly the right word. I've read some studies about this and there is serious debate amongst the experts in regard to sample mixing and diffusion. The reasoning I've read is that under that kind of pressure the ice is plastic and flows in unpredictable ways. It's the same thing that happens in the Earth's crust due to earthquakes and normal tectonic deformation. Layers can get tilted, inverted, or folded till they overlap in an S curve. That's why they try to take samples over a high spot (divide). It's thought that plastic deformation may be smallest there.

It's also thought that there MAY be capilary action of liquid water molecules amongst the ice crystals under that extreme pressure, and gasses may be transported and diffused more than previously assumed. It's hard to tell though. That's kind of a hot button topic in ice core research right now.
StillWind
2 / 5 (19) Feb 02, 2011
More evidence against the ridiculous AGW theory, then. If we accept the assertion that GG levels are higher now than at any time in the last 650k yrs..., then Earth should be the hottest it has been in that time, or something close.
Clearly it is not.
CO2 rise has always followed heating, and this has been definitively proven, and simple physics dismisses AGW theory.
Too bad that the only way that a scientist can get funding is to continue to bow to this apostasy, and that the media continues to sell the lie.
Earth's climate is changing all the time, and CO2 concentrations, especially at the minute quantities that exist in our atmosphere, are negligible.
GuruShabu
1.7 / 5 (18) Feb 02, 2011
This 650,000 y "spike" mentioned here is a huge farce!
I don't have time or space here to prove that but if you want to know more about it, read the book The Hockey Stick Illusion;Climategate and the Corruption of Science.
You can find it at Amazon.
Birger
4 / 5 (18) Feb 02, 2011
"The BEST climate for life on this planet is certainly much warmer, simply look back on the fossil record to see what the climate was like when there was the most life in the most regions of the world"

But the ultra-warm biosphere of the Jurassic was inhabited by species that were adapted to it. The same applies to the periods of great warmth during the early or middle Neogene.
Also, the marine life generally prefers colder conditions that allows more oxygen to be dissolved in the water. Arctic and antarctic seas have much more plankton, and thus more fish per volume unit.

Finally, the people living in Holland and Florida will find it hard to evolve into marine lifeforms in just a century...
Skeptic_Heretic
3.1 / 5 (8) Feb 02, 2011
More evidence against the ridiculous AGW theory, then. If we accept the assertion that GG levels are higher now than at any time in the last 650k yrs..., then Earth should be the hottest it has been in that time, or something close.
Well that isn't true in the least. If I double CO2 and lower solar irradiance it wouldn't necessarily be hotter.

Canux
5 / 5 (1) Feb 02, 2011
@GSwift7:

Thank you for your thoughtful reply. You've given me a lot more to research ;)
Caliban
4 / 5 (1) Feb 02, 2011
So, reading this article makes me wonder: are the Russians taking advantage of their Lake Vostok bore to simultaneously obtain an ice core record of the multi-Km thick ice cap they are drilling through? Don't remember seeing any writing to that effect in the most recent articles.
NotParker
1.5 / 5 (17) Feb 03, 2011
But the ultra-warm biosphere of the Jurassic was inhabited by species that were adapted to it.


I live in a mild coastal climate that fluctuates by 56C some years - -19C one day, +36C within 6 months.

I think we can adapt to +2C if it happens.

Of course as of the end of January the UAH temperature anomaly is -.01C below normal.

It isn't warming. Period.
GSwift7
2.5 / 5 (6) Feb 03, 2011
@ Caliban:

So, reading this article makes me wonder: are the Russians taking advantage of their Lake Vostok bore to simultaneously obtain an ice core record of the multi-Km thick ice cap they are drilling through?


The vostok cores are ice cores. I have no idea what you are talking about. They have not drilled all the way through the ice into the lake yet. There is not plan to do so to my knowledge for fear of contamination. In addition to the microbial contamination mentioned above, they also fear drilling fluid contamination. In fact they even worry about getting close to the lake because the drilling fluid could seep through the ice in the capilary action I mentioned above.
GSwift7
2.3 / 5 (4) Feb 03, 2011
Finally, the people living in Holland and Florida will find it hard to evolve into marine lifeforms in just a century


Most of the gloom and doom crowd these days is agreeing on a 1 meter rise in sea level in 90 years. That's not enough to drown Florida and Rotterdam, Netherlands is already 7 meters below sea level. Besides, if sea level does rise by 1 meter, that isn't going to be a uniform rise. Despite recent evidence that global sea level has risen, the sea level on the US East Coast and in the Gulf of Mexico seems to be falling, if you believe the NASA sea level measurements.

What may be a bigger long term problem for a few coastal areas around the world is land subsidence. As they use up the ground water (or oil in some cases), the land tends to sink rather quickly compared to the speed of other changes such as sea level or tectonics.
GSwift7
5 / 5 (8) Feb 03, 2011
P.S. Don't even talk to me about New Orleans. Whoever decided to build a city on a river delta was a moron. River deltas sink from the weight of sediment deposited around the region by the river. It's a neat phenomenon, where the sediment will build up and sink the land, then build up again continually. When you build a city in the middle of it, you create an area where no sediment will build up, but it will continue to sink along with the surrounding river delta. Ooops.
MorganW
3.5 / 5 (2) Feb 03, 2011
The BEST climate would be one that would allow me to go skiing 12months out of the year. The BEST climate for someone else, might be one that allows them to run naked through the jungle. Unfortunately, Neolithic man didn't get a choice - he had to adapt and relocate. Good thing he was so intelligent. Unlike some men today that would rather build their cities below the sea level and then bemoan rising sea levels.
MikeyK
4 / 5 (4) Feb 03, 2011
P.S. Don't even talk to me about New Orleans. Whoever decided to build a city on a river delta was a moron.


GSwift- nicely put. Have you ever seen Monty Python and The Holy Grial? There is a great a part of the film wherea king of the marshes explains to his son how he built a castle on a swamp...won't ruin the sketch for you, just watch it on youtube!
GSwift7
5 / 5 (2) Feb 03, 2011
lol, yes, that's one of my favorite movies.

Unlike some men today that would rather build their cities below the sea level and then bemoan rising sea levels


Unfortunately, building cities on deltas isn't only a modern mistake; It's a mistake that's been repeated many times, all the way back to pre-history. They found two old cities under the Nile delta not too long ago, for example. It seems that we never learn.
Caliban
4 / 5 (1) Feb 03, 2011
@ Caliban:

So, reading this article makes me wonder: are the Russians taking advantage of their Lake Vostok bore to simultaneously obtain an ice core record of the multi-Km thick ice cap they are drilling through?


The vostok cores are ice cores. I have no idea what you are talking about. They have not drilled all the way through the ice into the lake yet. There is not plan to do so to my knowledge for fear of contamination. In addition to the microbial contamination mentioned above, they also fear drilling fluid contamination. In fact they even worry about getting close to the lake because the drilling fluid could seep through the ice in the capilary action I mentioned above.


There was an article here only days ago, saying that they are indeed going to drill into the Lake, and take samples. To do so, they stopped short, and plan to drill through the last few feet with a new, uncontaminated drill. I forget the specifics, but there it is.
NotParker
1.5 / 5 (6) Feb 03, 2011
Parts of Sweden are rising at 11mm a year due to post-glacial rebound.

"Results of GPS data shows a peak rate of about 11 mm/year in the north part of the Gulf of Bothnia."
Skeptic_Heretic
3.7 / 5 (6) Feb 04, 2011
lol, yes, that's one of my favorite movies.

Unlike some men today that would rather build their cities below the sea level and then bemoan rising sea levels


Unfortunately, building cities on deltas isn't only a modern mistake; It's a mistake that's been repeated many times, all the way back to pre-history. They found two old cities under the Nile delta not too long ago, for example. It seems that we never learn.

Well very few of us today plan for terms longer than our appreciable lives. I can only assume that not being a forward thinker was more prevalent in the past when survival was more day to day than it is now for some of us.
GSwift7
4 / 5 (1) Feb 04, 2011
There was an article here only days ago, saying that they are indeed going to drill into the Lake, and take samples


Oh, I stand corrected about the plans to penetrate the lake. I wasn't aware that had changed. It looks like they are planning to use the existing hole from the core sample though, so there won't be any chance to get another core, in answer to your question. It looks like not everyone agrees that penetrating the lake is a good idea though.
yyz
5 / 5 (5) Feb 04, 2011
@Caliban, GSwift7,

Regarding scientific analysis of Lake Vostok ice cores, NOAA hosts a page with links to data and analysis of these cores:

h
ttp://www.ncdc.noaa.gov/paleo/icecore/antarctica/vostok/vostok_data.html
Howhot
2.3 / 5 (3) Feb 06, 2011


I live in a mild coastal climate that fluctuates by 56C some years - -19C one day, +36C within 6 months.

I think we can adapt to +2C if it happens.


You think you can adapt to it? No that's not right, YOU WILL have to adapt to it. Maybe more, and then more and then more. Also +2C is assuming a very optimist model. With the AGW (human caused warming) deniers, I would use a much less favorable model, and say 5.6C is probably close.
Howhot
4 / 5 (4) Feb 06, 2011
This 650,000 y "spike" mentioned here is a huge farce!
I don't have time or space here to prove that but if you want to know more about it, read the book XXX
You can find it at Amazon.


You can also find "An Inconvenient Truth" there too. Unfortunately the book you site is full of crap. Try

h
ttp://www.climate.gov

The condensed view is right there.

pubwvj
2.7 / 5 (3) Feb 06, 2011
Gotta sneak in "climate change" don't you? It's just history of climate.


Climate is always changing. *shrug* This is what people don't seem to understand. Generally it has been warmer in the past. I would prefer that it were warmer rather than colder. Ice ages are a HUGE bummer. Warming will open up more of the Earth to life, both plants and animals, that is currently too cold for most species. There is a lot of land up here in the north country that is frozen much of the year. But city cousins don't understand that. Unfortunately they miss the real issue: pollution.
Howhot
3.9 / 5 (7) Feb 07, 2011
My country cousin must be seeing all that I'm seeing; the weather extremes are just un-natural. Huge wind storm, huge Ice storm, incredible spring floods, burrning summer droughts, disappearing glaciers, north pole ice melt, Greenland ice-melt. And then, coral bleaching, ocean acidification, species extinction. Oh and then, the just ordinary stuff like temperature rise.

I'm a believer, it global warming, no doubt about it. What gets folks upset somehow, is it correlates in lockstep with mans rise, industrialization and industrrial exhaust (pollution) CO2.

PilotDave
1 / 5 (5) Feb 07, 2011
What everybody is overlooking is the phenomenon known as "Global Drying". There used to be an ocean in the region of the Grand Canyon, Monument Valley, and that area. Due to man's callous disregard for nature, all that ocean has now dried up and killed the wildlife. Many species went extinct. We must stop it now, before it is too late to reverse the process and put that ocean back. Think of all the people who will have to relocate if the water level of Lake Powell sinks further due to Global Drying.
Skeptic_Heretic
4.3 / 5 (6) Feb 07, 2011
What everybody is overlooking is the phenomenon known as "Global Drying". There used to be an ocean in the region of the Grand Canyon, Monument Valley, and that area. Due to man's callous disregard for nature, all that ocean has now dried up and killed the wildlife.
You're making ridiculous claims. The existence of the Rocky mountains is what has allowed the desert regions ot dry. The water evaporated over tens of thousands, if not millions of years in an age where primates didn't exist. How exactly are you going to blame death valley on mankind?

Your not helping the conversation or enlightening anyone when you make up silly shit like that.
GSwift7
5 / 5 (2) Feb 07, 2011
What everybody is overlooking is the phenomenon known as "Global Drying". There used to be an ocean in the region of the Grand Canyon, Monument Valley, and that area. Due to man's callous disregard for nature, all that ocean has now dried up and killed the wildlife. Many species went extinct. We must stop it now, before it is too late to reverse the process and put that ocean back. Think of all the people who will have to relocate if the water level of Lake Powell sinks further due to Global Drying


I assume you are joking. Keep in mind that sarcasm doesn't project very well in text. One of my local radio guys likes to say that computers should have a sarcasm font. lol.

Unfortunately, I've met many people who would believe every word of what you just said.

I think I just lost a million brain cells reading your post. Ouch.
Kingsix
not rated yet Feb 07, 2011
The entire global warming debate (IMO) is one that is defined by our need for self preservation, it is a noble cause. Global climate change, that we probably will see, whether it is due to our use of the planet or due to continuing cyclical climate cycles will probably cause the extinction of many species, maybe eventually us. Nature has obviously adapted to these types of changes before, and it probably will again.
We are a smart species and therefore will probably be able to whether the change as well.
It just won't be nice to see parts of the land get submerged, and some cute animals drown and go extinct. Morality tugging at our heart strings.
Not that we all shouldn't pollute less.
Kingsix
5 / 5 (1) Feb 07, 2011
What everybody is overlooking is the phenomenon known as "Global Drying". There used to be an ocean in the region of the Grand Canyon, Monument Valley, and that area. Due to man's callous disregard for nature, all that ocean has now dried up and killed the wildlife. Many species went extinct. We must stop it now, before it is too late to reverse the process and put that ocean back. Think of all the people who will have to relocate if the water level of Lake Powell sinks further due to Global Drying.

Oh my gosh really? Global Drying? Wait a second, wasn't the Grand Canyon carved by the river over a very very long time?

HAhaHA, are you also a Scientologist?
PilotDave
Feb 07, 2011
This comment has been removed by a moderator.
PinkElephant
4.3 / 5 (6) Feb 07, 2011
@PilotDave,

First of all 2 degrees is a global average. It is a spatial average, in that there will be less warming at the equator, and considerably more at the poles. It is a temporal average, in that both extreme highs and extreme lows will occur at higher temperature points. To put it in perspective, consider that the difference between normal body temperature and high fever, is just 3 degrees C.

Permafrost will melt across the arctic, transforming those lands into endless, impassable, methane-belching swamps (methane, BTW, will amplify the greenhouse effect further still.) If you think mosquito-plagued marshlands are going to be useful to anyone, I suggest you move to Siberia straight away: no point waiting.

Oceans will be less productive. Most of the equatorial lands will get drier. Extreme weather events (floods, in particular) will be more frequent.

Yeah, we will adapt. But it's going to cost a lot more than we're "saving" currently by using "cheap" fossil fuels.
PilotDave
1 / 5 (2) Feb 16, 2011
Humans are so self-important. First we think we're at the top of the evolutionary ladder. Now, despite the fact that we can't even predict tomorrow's weather, we think we can change it.

You guys need to get up in an airplane once in a while and discover the VASTNESS of this planet, and the utter impossibility that anything we could do could POSSIBLY affect such a huge expanse of air and water.

Much as we had NOTHING to do with the complete evaporation of the entire ocean that used to sit where Monument Valley now sits. Try to imagine what kinds of NATURAL climate changes were required to do that, and you can see that NATURAL changes will always trump whatever measly things mankind can do.

Just watch this next solar flare.
Howhot
3.7 / 5 (3) Feb 16, 2011
You guys need to get up in an airplane once in a while and discover the VASTNESS of this planet, and the utter impossibility that anything we could do could POSSIBLY affect such a huge expanse of air and water.


Where were you during the Gulf Oil well spill? Utterly impossible to soak the huge expanse of the gulf in crude oil? It seems that we've proven the fact that it is easily do-able to create an environmental disaster the size of Texas with the last one.