Friday, December 14, 2007

It Was So Much Warmer Then

It looks like the polar bears will survive the current warming.

"We have this specimen that confirms the polar bear was a morphologically distinct species at least 100,000 years ago, and this basically means that the polar bear has already survived one interglacial period," explained Professor Ingolfsson.

"And what's interesting about that is that the Eeemian - the last interglacial - was much warmer than the Holocene (the present).

"This is telling us that despite the ongoing warming in the Arctic today, maybe we don't have to be quite so worried about the polar bear. That would be very encouraging."
So what do we know about the Eeemian?
The Eemian interglacial era (known as the Sangamon interglacial in North America, the Ipswichian interglacial in the UK, and the Riss-Würm interglacial in the Alps) is the second-to-latest interglacial era of the Ice Age. It began about 131,000 years ago. Changes in orbital parameters from today (greater obliquity and eccentricity, and perihelion), known as the Milankovitch cycle, probably led to greater seasonal temperature variations in the Northern Hemisphere, although global annual means temperatures were probably similar to those of the Holocene. The Eemian climate is believed to have been about as stable as, but probably warmer than that of, the Holocene (see ice core). The warmest peak of the Eemian was around 125,000 years ago, when forests reached as far north as North Cape (which is now tundra) in northern Norway well above the Arctic Circle at [show location on an interactive map] 71°10′21″N, 25°47′40″E. Hardwood trees like hazel and oak grew as far north as Oulu, Finland. Sea levels at that time were 4-6 meters higher than they are now, indicating greater deglaciation than today (mostly from partial melting of the ice sheets of Greenland and Antarctica). One study published in July 2007 found evidence that Dye 3 was glaciated during the Eemian, which implies that Greenland could have contributed at most 2m to sea level rise. Scandinavia was an island due to the inundation of vast areas of northern Europe and the West Siberian Plain.

At the peak of the Eemian, the northern hemisphere winters were generally warmer and wetter than now, though some areas were actually slightly cooler than today. Trees grew as far north as southern Baffin Island in the Canadian Arctic Archipelago instead of only as far north as Kuujjuaq in northern Quebec, and the prairie-forest boundary in the Great Plains of the United States lay further west — near Lubbock, Texas, instead of near Dallas, Texas, where the boundary now exists. The era closed as temperatures steadily fell to conditions cooler and drier than the present, and by 114,000 years ago, a glacial era had returned.
Did any one notice the bit in the first paragraph about Earth being in an Ice Age? And the fact that the interglacial periods are only temporary respites. We really need to worry more about a return of an ice age. Very few crops do well under ice.

7 comments:

William said...

Yes, the Eemian was much warmer than today coinciding with the roughly 100,000 yr Milankovitch cycle. CO2 rise also corresponded to these cycles but never spiked higher than 300ppm according to ice cores. However it did during the Paleocene–Eocene Thermal Maximum, a Global Warming event 55 million yrs ago that dwarfed the Milankovitch cycle warming coinciding with glacial cycles. Indications show the earth CO2 balance is out of control, presently rising faster and spiking higher than any time in human history, and that we are headed toward a warming event similar to that of the PETM. New data shows all the most agressive computer models of global warming predictions have been exceeded. The PETM caused a change in ocean chemistry and mass extinctions.

LarryD said...

Ice cores from Siple, Antarctica, show CO2 at 328 ppmv. This would have been laid down in 1890 AD.

Simplistic reading of ice cores for CO2 levels have been criticized by Prof. Zbigniew Jaworowski
Chairman, Scientific Council of Central Laboratory for Radiological Protection
Warsaw, Poland.
"Determinations of CO2 in polar ice cores are commonly used for estimations of the pre-industrial CO2 atmospheric levels. Perusal of these determinations convinced me that glaciological studies are not able to provide a reliable reconstruction of CO2 concentrations in the ancient atmosphere. This is because the ice cores do not fulfill the essential closed system criteria. One of them is a lack of liquid water in ice, which could dramatically change the chemical composition the air bubbles trapped between the ice crystals. This criterion, is not met, as even the coldest Antarctic ice (down to –73oC) contains liquid water[2]. More than 20 physico-chemical processes, mostly related to the presence of liquid water, contribute to the alteration of the original chemical composition of the air inclusions in polar ice[3].

"One of these processes is formation of gas hydrates or clathrates. In the highly compressed deep ice all air bubbles disappear, as under the influence of pressure the gases change into the solid clathrates, which are tiny crystals formed by interaction of gas with water molecules. Drilling decompresses cores excavated from deep ice, and contaminates them with the drilling fluid filling the borehole. Decompression leads to dense horizontal cracking of cores, by a well known sheeting process. After decompression of the ice cores, the solid clathrates decompose into a gas form, exploding in the process as if they were microscopic grenades. In the bubble-free ice the explosions form a new gas cavities and new cracks[4]. Through these cracks, and cracks formed by sheeting, a part of gas escapes first into the drilling liquid which fills the borehole, and then at the surface to the atmospheric air. Particular gases, CO2, O2 and N2 trapped in the deep cold ice start to form clathrates, and leave the air bubbles, at different pressures and depth. At the ice temperature of –15oC dissociation pressure for N2 is about 100 bars, for O2 75 bars, and for CO2 5 bars. Formation of CO2 clathrates starts in the ice sheets at about 200 meter depth, and that of O2 and N2 at 600 to 1000 meters. This leads to depletion of CO2 in the gas trapped in the ice sheets. This is why the records of CO2 concentration in the gas inclusions from deep polar ice show the values lower than in the contemporary atmosphere, even for the epochs when the global surface temperature was higher than now. "

William said...

Prof. Zbigniew Jaworowski is not a climate scientist and his assertions are based primarily on his research published 15 yrs ago: "Do glaciers tell a true atmospheric CO2 story?" 1992.

Increases in CO2, and CH4 concentrations in the Vostok core are similar for the last two glacial-interglacial transitions, even though only the most recent transition is located in the brittle zone. Such evidence argues that the atmospoheric trace-gas signal is NOT strongly affected by the presence of the brittle zone as Jaworowski asserts.

Hans Oeschger founder of the Division of Climate and Environmental Physics at the Physics Institute of the University of Bern commented on Jaworowski's research before he died: "...Some of (Jaworowski's) statements are drastically wrong from the physical point of view".

The scientific community has debunked Jaworoski, his assertions are not accepted as valid.

M. Simon said...

I was unaware that you had to be a climate scientist to do physical chemistry.

You learn something new every day.

However, as a non-degreed aerospace engineer, I am not cowed by authority. I try to evaluate data and conflicting opinions on their merits.

Since I haven't read the paper in question or the counter arguments I can't comment.

The fact that the author is not a climate scientist is just an appeal to authority. Those don't work well here.

=======================

William,

Yeah. Unprecedented rise in temps. A catastrophe at hand.

We can survive temperature variations of 50 deg F in an hour but .01 deg per year will cause untold damage.

Makes sense to me.

We can breathe air with at least 1,000 ppmv CO2, but all the rest of the fauna will die out from the increase of 2 or 3 ppmv per year from our current level of around 370 ppmv.

Flora will do just fine. In fact for many plants their best growth rates happen at 5,000 ppmv. Why current CO2 levels are at near starvation for those plants. We need efforts to make the planet more plant friendly by adding as much CO2 to the atmosphere as we can as soon as possible.

So let me ask: why do you favor starving the plants? Are you some kind of evil fiend?

The Geologic History of CO2.

I'm sure you can explain why the 2,000 ppmv CO2 in the atmosphere at the beginning of the Cretaceous was not a problem but the current 370 ppmv is.

And the dreaded CO2 balance. There is a lot to be afraid of.

As I understand it the planetary system has no equilibrium state. If that is the case how can it be out of balance when it was already out of balance?

So here is what we do. Shut down all fossil fuel plants and oil production around the world at once. We should be able to kill off at least 2 or 3 billion people within a year if we do that and the survivors could profit by burying the dead. I think with the right measures we could get human population down to 250 million or so in less in 5 years.

I think that would be the final solution to the CO2 problem. How about you?

====

Me? I don't think CO2 is much of a problem. However, if you do may I suggest you give up winter heating, summer cooling and all use of fossil fuel derived transportation transportation (including food delivered to grocery stores) at once.

If you really believe things are so dire you need to act at once. No time to lose.

Plus you need to stop breathing. It wastes oxygen and pollutes the environment with CO2 and other noxious gases. Now I'm not a purist about this by any means. I think if you practice not breathing for two hours straight every day that would be a start until you can go the full 24 without breathing.

Sacrifices must be made. You go first.

William said...

Regarding sacrifices, look at my opinion in my comment on the previous post.

I would like to see one skeptic for a change that isn't arguing on the basis of energy industry agendas, lock step conservative ideology, or fear of gov't control and sacrifice.

Does the science mean anything to anyone? It doesn't take a climate scientist to see that this is not part of a natural Milankovitch ice age cycle.

We can look to the Paleocene/Eocene Thermal Maximum to see that such climate change - "only" a 5-8 C. temp rise over a few thousand years can vastly affect ocean chemistry and cause a mass extinction event.

The temp. increase projections are being revised ever upward and previous 'alarmist' projections (artic ice free by 2050) now seem very conservative. These projections certainly point toward a PETM type event.

Chatterton said...

Msimon said..

The fact that the author is not a climate scientist is just an appeal to authority. Those don't work well here.

Funny. You sure have gone to great lengths to legitimize your IEC fusion fantasy by pointing to Bussard's qualifications (even though he stopped doing real science over 20 years ago!).

You're a cherry picker supreme!

M. Simon said...

Credentials only tell you what a person has officially studied not the quality of their pronouncements.

Freeman Dyson is non-degreed. I think he has a lot of interesting things to say.

Of course it could just be my bias against credentialism.

As to Bussard doing no physics. What exactly was he doing in the lab at EMC2 (which the US Navy is currently funding)?

You know Chatt, you have a number of opinions on Bussard that are not backed up by facts. I have discussed Dr. B's work with a number of people who actually worked in his lab and their accounts do not square with yours. How did you come by your opinion?