Global Warming and Cooling.

I have been frustrated by the antics of the AGW alarmists. Scientific American, for example, has lost whatever reputation it once had for objective science. (pdf) In an another example, the actions of Michael Mann should make for an interesting discovery in his suit against Mark Steyn.

Today, I find a nice discussion of global warming and cooling over the past epoch. The Greenland ice cores are, or should be, the gold standard of temperature measurement. For example.

Records of past temperature, precipitation, atmospheric trace gases, and other aspects of climate and environment derived from ice cores drilled on glaciers and ice caps around the world. Parameter keywords describe what was measured in this data set. Additional summary information can be found in the abstracts of papers listed in the data set citations.

Now, to the data.


This period, from 1400 to 1900, is called the Little Ice Age.

Wikipedia is not reliable on the topic of global climate change because they have editors and contributors who are not above altering information to support the political issue of AGW. However, even they have included an honest chart showing the Little Ice Age and the preceding Medieval Warm Period.


Here is shown the Medieval Warm Period although their chart includes the spurious late 20th century warming which is based on altered data. Professor Mann, however, has no such period shown in his chart.


Note the absence of the warm period in his chart. This has been widely debunked, especially by statisticians, and he is suing Mark Steyn, a conservative writer for libel on very shaky grounds. Discovery should be interesting in that case and I would not be surprised to see Mann withdraw his suit. If he does so, Steyn and the other defendants should file a claim for their legal costs. I was once involved in a malicious prosecution case and I have no sympathy for Mann and his enablers at Penn State.

in order to defend itself NR would be entitled to seek discovery, and in the process obtain access to e-mails and other records that Mann has, thus far, resisted disclosing in various freedom-of-information suits prompted by ClimateGate.

And that is the problem for Mann. Possibly a problem for Mann that is. The lawyers defending NR get to crawl all over all those documents that he’s been so careful about making sure have not been released. Now, as we know absolutely, Dr. Mann has not been hiding anything at all, not even the odd decline, in his academic work.


Here is a chart of temperatures on a longer scale. This shows the ice core temperatures from 800 AD to 1800, a thousand years. The 1850 end of the Little Ice Age is clearly seen and the 20th century warming is almost certainly a result of this cycle, which has nothing to do with CO2 or the Industrial Revolution. The Medieval Warm Period peaks at about 1000 AD, the peak of the Norse settlement of Greenland.

The Little Ice Age has been well documented in paintings and literature. For example:


This Norse church in Greenland contains the last record of the settlement. A marriage record dated 1408. After that, the cold closed in.

We can go back to the beginning of the Holocene epoch and what do we see ?


At the very beginning, we see the temperature rise from the last major ice age. Throughout this period, also known as “The Age of Man”, we see an average temperature that is close to the maximum in the second graphic. Remember, these are Greenland ice cores so 32 degrees is normal.

In fact for the entire Holocene — the period over which, by some odd coincidence, humanity developed agriculture and civilization — the temperature has been higher than now, and the trend over the past 4000 years is a marked decline. From this perspective, it’s the LIA that was unusual, and the current warming trend simply represents a return to the mean. If it lasts.

Some worry that another ice age is coming. Certainly this was a worry in the 1970s.


Journalism school is not strong on science or statistics.

Let us think about an even longer time line.


Here are ice cores from Antarctica showing the pattern of the last 400,000 years. The climate seems to be subject to regular oscillations on a scale of about 100,000 years. In fact ice ages seem pretty much normal for this planet.


In fact, this one seems almost benign compared to history. The issue of CO2 effect on climate is obviously (to me who took calculus) a benign influence. There have been some attempts to quantify this, but data is weak and bias is strong.

In other words, we’re pretty lucky to be here during this rare, warm period in climate history. But the broader lesson is, climate doesn’t stand still. It doesn’t even stand stay on the relatively constrained range of the last 10,000 years for more than about 10,000 years at a time.

Does this mean that CO2 isn’t a greenhouse gas? No.

Does it mean that it isn’t warming? No.

Maybe more CO2 is the proper response.

11 thoughts on “Global Warming and Cooling.”

  1. I predict in the next 5 years the thought of Manmade Global Warming will have been forgotten and its adherents will move on to the Next Big Thing.

    To me the most obvious explanation is the activity of the sun.

  2. Thanks, Michael. Very informative.

    I always thought that solar influences trumped others, but I’m now convinced that the reversal of the temperature increases happened in 2008, when Barry promised that his election would cause the sea levels to fall (based on reversing ice cape melting). Lo and behold, he did it (this year anyway). I have seen the light! This may mean that someone like Barry only comes around about every 10,000 years. I sure hope so.


  3. Another informative site is, although it gets really technical.
    McIntyre was one of the first to question the hockey stick graph. He was the nemesis of Mann and Mann’s co-conspirators website for years. He sticks to hard science in order to counter the argument of the climate scientists that the concepts are so complicated only they are unquestionably qualified to judge it.

    A few months ago he posted this about the even more damning Antarctic ice cores

    The late 20th century warming was a just a return to the mean

  4. Grurray, note that the Wiki article, while it describes the site, discusses “greenhouse gases” as the purpose. There is a similar misunderstanding elsewhere in the alarmist world. The implication is that CO2 is measured and the results are disputed on the theory that CO2 can disperse through the ice. The actual measurement is of Oxygen 18 ratios

    In ice cores, mainly Arctic and Antarctic, the ratio O-18/O-16 (δ18
    O) can be used to determine the temperature of precipitation through time. Assuming that atmospheric circulation and elevation has not changed significantly over the poles, the temperature of ice formation can be calculated as equilibrium fractionation between phases of water that is known for different temperatures. Water molecules are also subject to Rayleigh fractionation[2] as atmospheric water moves from the equator poleward which results in progressive depletion of O-18, or lower δ18
    O values. In the 1950s, Harold Urey performed an experiment in which he mixed both normal water and water with oxygen-18 in a barrel, and then partially froze the barrel’s contents.
    The ratio O-18/O-16 (δ18
    O) can also be used to determine paleothermometry in certain types of fossils. The fossils in question have to show progressive growth in the animal or plant that the fossil represents. The fossil material used is generally calcite or aragonite, however oxygen isotope paleothermometry has also been done of phosphatic fossils using SHRIMP.[3] For example, seasonal temperature variations may be determined from a single sea shell from a scallop. As the scallop grows, an extension is seen on the surface of the shell. Each growth band can be measured, and a calculation is used to determine the probable sea water temperature in comparison to each growth. The equation for this is:

    T = A + B \cdot \left( \left( \delta {}^{18} \text{O} \right) \text{calcite} – \left( \delta {}^{18} \text{O} \right) \text{water} \right)

    Where T is temperature in Celsius and A and B are constants.

    For determination of ocean temperatures over geologic time, multiple fossils of the same species in different stratigraphic layers would be measured, and the difference between them would indicate long term changes.[4]

    The O18/16 ratio is not known to change.

  5. From 2005:

    Also, Paleoclimate Data, Milankovitch Cycles, and Extending Energy Balance Models (slides 15, and 16 especially):

    This is not just math theory. As well as ice core and foraminifer and sea sediment evidence, there’s strong geologic evidence for these cycles as well. In Ontario, for example, there are layered sediments of glacial till (an admixture of powdered rock and rock debris) and organic soils, which are radio-carbon datable. Glacial till – organic laden soil – glacial till – organic laden soil. Warming, cooling, warming, cooling. Ice age, warm period, ice age, warm period.

    The current Pleistocene Ice Age began roughly 3 mya, when the Isthmus of Panama formed from island arcs and sea floor material that collided with the Caribbean Plate. Plate boundary volcanism then connected the North and South American Plates together, cutting off the then equatorial ocean current and diverting it into the Gulf of Mexico and up the Atlantic coast as the Gulf Stream. That carried warm, moist air up to the Arctic latitudes where the moisture condensed and fell on North America as increased snowfall. So began the Pliestocene. It will continue as long the Isthmus remains in place. We are currently in a Milkankovitch driven interglacial period. All of human civilization has developed and existed within this interglacial, about the last 12-15,000 years.

  6. It’s not the warming or cooling or pause in either—it’s the massively collectivist policy proposals which immediately became the default positions for anyone and everyone who wanted to claim the morally superior high ground in dealing with the “climate crisis”.

    The deepest issue, and the gravest threat to the continuation of American society as a relatively free place within which to live, work, and raise a family, is the fact that an endless list of coercive state policies to deal with any and every problem has become THE moral and desirable course of action for so many of our citizens.

    The danger to our social order is not a change in the climate, but the change in our moral structures which elevates coercive state programs over the individual and/or cooperative actions of concerned and responsible free citizens acting as creative agents to solve specific problems as they arise.

    The true significance of warming alarmism is that, as in so many other alleged social crises, only collectivist, coercive statist actions are considered at both the national and international levels.

    This is a moral inversion of the basest kind, and delusional in the extreme—only a completely irrational mind could advance the contention that the corrupt and incompetent ruling elites of this and other nations could successfully solve such complex problems through political action.

    The entire history of the 20th century, much less the pre-technological history of governments in general, screams that such a belief is utterly delusional, and more the type of belief often seen in millennial cults than in a rational approach to solving real problems in the real world.

    The continuing revelations as to the over-hyped alarmism of much of the AGW theory only reinforces the suspicion that the entire exercise was more of a stalking horse for collectivist ideology than a reasoned approach to a real, critical societal problem.

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