Saturday, May 16, 2009

Coming Ice Age?

The debate about climate change cuts both ways. Is it warming or cooling? This is not merely an academic argument when the government wants to "cap and trade" carbon dioxide emissions, which is merely a thinly disguised tax, projected to cost taxpayers BILLIONS. We need to carefully think these things out.
Peter

The Coming Ice Age
(source)
By David Deming
Those who ignore the geologic perspective do so at great risk. In fall of 1985, geologists warned that a Columbian volcano, Nevado del Ruiz, was getting ready to erupt. But the volcano had been dormant for 150 years. So government officials and inhabitants of nearby towns did not take the warnings seriously. On the evening of November 13, Nevado del Ruiz erupted, triggering catastrophic mudslides. In the town of Armero, 23,000 people were buried alive in a matter of seconds.

For ninety percent of the last million years, the normal state of the Earth's climate has been an ice age. Ice ages last about 100,000 years, and are punctuated by short periods of warm climate, or interglacials. The last ice age started about 114,000 years ago. It began instantaneously. For a hundred-thousand years, temperatures fell and sheets of ice a mile thick grew to envelop much of North America, Europe and Asia. The ice age ended nearly as abruptly as it began. Between about 12,000 and 10,000 years ago, the temperature in Greenland rose more than 50 °F.

We don't know what causes ice ages to begin or end. In 1875, a janitor turned geologist, James Croll, proposed that small variations in Earth's orbit around the Sun were responsible for climate change. This idea enjoyed its greatest heyday during the 1970s, when ocean sediment cores appeared to confirm the theory. But in 1992, Ike Winograd and his colleagues at the US Geological Survey falsified the theory by demonstrating that its predictions were inconsistent with new, high-quality data.

The climate of the ice ages is documented in the ice layers of Greenland and Antarctica. We have cored these layers, extracted them, and studied them in the laboratory. Not only were ice ages colder than today, but the climates were considerably more variable. Compared to the norm of the last million years, our climate is remarkably warm, stable and benign. During the last ice age in Greenland abrupt climatic swings of 30 °F were common. Since the ice age ended, variations of 3 °F are uncommon.

For thousands of years, people have learned from experience that cold temperatures are detrimental for human welfare and warm temperatures are beneficial. From about 1300 to 1800 AD, the climate cooled slightly during a period known as the Little Ice Age. In Greenland, the temperature fell by about 4 °F. Although trivial, compared to an ice age cooling of 50 °F, this was nevertheless sufficient to wipe out the Viking colony there.

In northern Europe, the Little Ice Age kicked off with the Great Famine of 1315. Crops failed due to cold temperatures and incessant rain. Desperate and starving, parents ate their children, and people dug up corpses from graves for food. In jails, inmates instantly set upon new prisoners and ate them alive.

The Great Famine was followed by the Black Death, the greatest disaster ever to hit the human race. One-third of the human race died; terror and anarchy prevailed. Human civilization as we know it is only possible in a warm interglacial climate. Short of a catastrophic asteroid impact, the greatest threat to the human race is the onset of another ice age.

The oscillation between ice ages and interglacial periods is the dominant feature of Earth's climate for the last million years. But the computer models that predict significant global warming from carbon dioxide cannot reproduce these temperature changes. This failure to reproduce the most significant aspect of terrestrial climate reveals an incomplete understanding of the climate system, if not a nearly complete ignorance.

Global warming predictions by meteorologists are based on speculative, untested, and poorly constrained computer models. But our knowledge of ice ages is based on a wide variety of reliable data, including cores from the Greenland and Antarctic ice sheets. In this case, it would be perspicacious to listen to the geologists, not the meteorologists. By reducing our production of carbon dioxide, we risk hastening the advent of the next ice age. Even more foolhardy and dangerous is the Obama administration's announcement that they may try to cool the planet through geoengineering. Such a move in the middle of a cooling trend could provoke the irreversible onset of an ice age. It is not hyperbole to state that such a climatic change would mean the end of human civilization as we know it.

Earth's climate is controlled by the Sun. In comparison, every other factor is trivial. The coldest part of the Little Ice Age during the latter half of the seventeenth century was marked by the nearly complete absence of sunspots. And the Sun now appears to be entering a new period of quiescence. August of 2008 was the first month since the year 1913 that no sunspots were observed. As I write, the sun remains quiet. We are in a cooling trend. The areal extent of global sea ice is above the twenty-year mean.

We have heard much of the dangers of global warming due to carbon dioxide. But the potential danger of any potential anthropogenic warming is trivial compared to the risk of entering a new ice age. Public policy decisions should be based on a realistic appraisal that takes both climate scenarios into consideration.

David Deming is a geophysicist and associate professor of Arts and Sciences at the University of Oklahoma.
COMMENTS:

5 comments:

Anonymous said...

Posted by: sentient May 14, 12:24 PM Report Abuse
Reply


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Dr. Deming is absolutely correct. Allow me to add to the factual base. We live today in the Holocene epoch, the past 11,500 years since we melted our way out of the Wisconsin ice age. All, and this needs repeating, ALL of human civilization has occurred during THIS interglacial. Only cave paintings are available beyond 10k years ago. It is called the Wisconsin ice age for the simple reason that this is where the terminal moraines are found for the miles thick ice sheets that covered the northern hemisphere. Stepping back the previous three are termed the Illinoisan, Kansan and Nebraskan. Think about that for a moment. Miles thick ice sheets extending as far south as Kansas.

According to the National Research Council (Abrupt Climate Change -Inevitable Surprises, 2002), half of the melting that brought us out of the Wisconsin ice age occurred in less than a decade. And that does not include Dansgaard-Oeschger events which have an average period of 1,500 years, the same sawtooth shape as the major ice age events (abrupt and dramatic warming, then a bumpy ride into the deep ice age freeze), and an average near instantaneous warming of 8-10C with outliers up to 16C (about 60F). So if you are concerned about the maximum IPCC predicted rise of 2C in a century (this one), then our signal will be hard to pick out from the natural background noise of natural climate change, which reliably can result in those 8-16C jumps in from a few years to less than a decade. Interestingly, in all typical proxy records (ice cores, tree-ring cores, ostracod shells in deep sea cores, pollen studies etc.) temperature rises and from centuries to millenia later CO2 rises, temperatures fall, and the then much later CO2 levels fall.

So temperature drives GHGs, not the other way around for as far back as we can see it, and the Greenland cores see it particularly well back to the Eemian, the interglacial which preceded this one, the Holocene. Now, if you are concerned about sea level rise, then the 0.6 meter rise in sea levels by 2100 is obviously significant. But how significant? About 7000-6000 years ago, during the Holocene Climate Optimum, sea levels topped out only a mere 6 meters above present, ten times higher than what is considered a credible prediction. How about during the Eemian, the interglacial which preceded this one and the one in which Homo sapiens debuts in the fossil record? sea level highstands reached only slightly higher than today, a paltry 20 meters (52 meters have been reported for locations in Siberia).

And what does it take to make a miles thick ice sheet? Surprisingly enough there is some evidence that would suggest water is involved as the primary constituent of ice. And not all that much water at that. The average drop below present day seal levels is almost negligible, only about 300 feet on average. The NRC states that the average swing between an ice age and an interglacial is a relatively easy to geoengineer 400 feet.

So we better get cracking. And the place to start is with CO2. It will be a good learning experience. And as we all know, a mistake is a learning experience you commit more than once. So focusing the first time on CO2 for climate engineering will in no way qualify as a mistake, it will be a learning experience, perhaps of the best kind. Especially from the psychological point of view.

You see a fairly exhaustive psychological study completed in the 1970's found that the human being is nine times more susceptible to rumor than it is to fact. Call it the 9TR for short. It is relatively easy to prove with this simple question: which, of all mankind's religions is the correct one? In your deliberations you are allowed to consider Zeus, and the pantheon of gods once resident on Mt. Olympus, or Rah, the former sun god of ancient Egyptian society, or perhaps you might select Ishtar, the god that preceded Mohammed and the establishment of Islam, a religion still practiced today.

Which brings us to denial. Assume, for a moment, that the GHG-AGW theory is correct. Remember, this is based on predictions, not actual facts, but potential future facts, facts which have yet to occur (not substantially different from a rumor). Integrate with that what Dr. Deming has correctly reported from the factual knowledge base we have painstakingly gleaned from vast proxy records, that ice ages tend to begin very quickly, from just a few years to no more than decades. If we give equal status to future fantasies (those would be model results which have yet to duplicate a known past climate change event) and to facts (things which have occurred and are not in dispute), then the vast majority who believe in GHG-AGW may find themselves with the embarrassing need to spew out as much GHGs as possible (instead of reducing them) in order to cushion our next slide into an ice age.

Understand of course, that all six interglacials dating back to the Mid Pleistocene Transition (when we shifted from the 41k yr ice age/interglacial couple to the 100k yr one we have been on for the past 800k years) have each lasted roughly half of a precessional cycle (a precessional cycle is 23k years long). So, at 11,500 years, precisely half a precessional cycle, this one, the Holocene, is pretty much kaput. When you get your mind wrapped around that fact, perhaps you, as I, will begin to ponder just what an ice age means as regards our own evolution. Spend some time researching climate and hominid evolution, and you will soon come to realize that it may just have been responsible for what we know is the most rapid encephalization of any species yet recorded in the fossil record, taking us from a 500cc braincase to a 2,500 year braincase in just 3 million years (or 33 major climate change events). Which puts a fascinating spin on climate change. It just could be that climate change is the only thing known to smarten members of the genus Homo up. If this really is the case, then it occurs to me that we really could use an ice age right about now.

Meanwhile, enjoy the interglacial. While it lasts................

Peter said...

I agree.

Anonymous said...

My best advice would be to watch videos of GW and adopt his unique accent. Instead of saying goodbye to your friends start saying, "Remember the Alamo." Learn about guns, hunting and farming. When you have got that down move to Texas, buy a few farmable and defendable acres and endear yourself to the local population. Those rural Texans stick together.

Juhani said...

It has been thought that there have been several Ice Ages on the Earth. It has even been said that tropical and hot areas like the Sahara, Africa, Saudi Arabia, Yemen, Australia, India, Madagascar, and South America were covered with a large continental glacier tens of millions of years ago. The latest Ice Age is assumed to have started "just" about 500,000 years ago and ended 10,000 years ago. The ice sheets are believed to have covered at their widest 55 million square meters, and the thickness of the ice was at most over 3 kilometers (about 1.8 miles).

What should we think about the Ice Age? Have we any reason to believe in it? Maybe the signs that have been interpreted as signs of an Ice Age were caused by something else?

http://koti.phnet.fi/elohim/Has_there_ever_been_the_ice_age.html

Peter said...

Juhani,
If you try to mix science and religion you're going to become very confused. I say stay with one or the other.