Recent work on antarctic ice cores has now given us a good record of atmospheric composition over the last 650,00 years. The work shows that CO2 and other “greenhouse” gasses are now at their highest levels ever over that period. All the news stories are quoting scientists saying that this new information proves that human-emitted gasses are causing global warming.
They’re wrong. In fact, the core samples might just show the opposite.
(Note: I’m working from secondary sources here as I can’t bring myself to plink down the $10 to get the actual paper from Science. If I get more information later I will update this post.)
The fundamental problem is that the core samples show very little correlation between levels of greenhouse gasses and global temperatures. For example, the core samples showed conclusively that atmospheric gasses have no effect on the cycles of ice ages. Since the last ice age, there have been several periods of unusual global warming or cooling that also do not correlate strongly with greenhouse gas levels.
Even the weak correlations that do exist may not tell us much, because a changing climate changes the composition of the atmosphere. For example, methane, which is about 23 times more powerful as a greenhouse gas than CO2, arises from the decomposition of biomass by bacteria. Since warmer periods sustain more biomass, they also create more methane. So methane levels rise and fall with warming and cooling cycles even though the levels may have little to do with driving the cycles themselves. Conversely, CO2 levels may fall as a climate warms because an expanding biomass absorbs carbon. (Or maybe increased biomass leads to increased CO2 production. There is a lot of debate.) So as a general rule, we would expect warmer periods would produce more greenhouse gasses than cooler periods just by creating more biomass. The cause-and-effect relationship could be the exact reverse of that portrayed by anthrogenic-global-warming advocates.
What the core samples really show is that atmospheric gasses are not the primary drivers of global temperature change. Ice ages are the result of the Milankovitch cycles in the precession of the earth’s axis. Shorter term climate changes, on the order of decades or centuries, correlate with sunspot activity. Volcanos cause spikes of cooling followed by warming over the span of a few years. In the climatological record, it is more likely that atmospheric gas-level changes result from climate change than that the gas levels drive the climate change. (Of course, feedback loops exist which complicate any analysis.)
In order to determine whether human-emitted gasses drive climate change we first have to eliminate the effects of all the natural drivers. In the main, this has not been done. For example, even though we know that increased sunspot activity correlates with increased temperature on earth, we do not know why, even on a theoretical basis, this is so. None of the sophisticated climate models on which the anthrogenic-global-warming hypothesis are based account for sunspot activity at all. Interestingly enough, the last 30 years of increasing global temperatures have also tracked 30 years of unusually high sunspot activity.
One of the reasons I persist in viewing anthrogenic global warming as more of a social and political phenomenon than a scientific one is the way in which a kind of scientific-media-political complex bends every observation to fit the hypothesis, with few if any qualifications. Every media story I have read on the antarctic ice cores says that the cores show that humans are causing global warming, when in fact the cores merely show that greenhouse gas levels are high. To assert that the high levels of the gasses cause warming one must first assume that the gasses drive the warming. (This is a logical fallacy called begging the question.)
Even if information is included that would contradict the hypothesis, it is often couched in terms that appear to support it. For example, the story linked to above uses the lack of correlation between gas levels and ice ages to attack those who argue that increased CO2 levels might fend off an impending ice age. The fact that the lack of correlation shows that atmospheric gasses are not primary drivers of major climate change isn’t even mentioned as a possibility.
I think that significant segments of the population are so invested in the idea that industrial production must be placed under political control that they will instantly glom onto any idea that gives them the slightest justification for doing so. They try to panic the rest of the population with predictions of cataclysm while vilifying anyone who questions the premise. I think that cataclysmic anthrogenic global warming has all the earmarks of a politically driven hysteria. I think it will turn out to be as much of an exercise in mass self-deception as the “Energy Crisis” of the ’70s turned out to be.
The way that the results of the antarctic core sampling project have been portrayed just reinforces my belief that this will be so.
A good post. For further information debunking anthropogenic climate change have a look at these sites.
http://www.sepp.org/
http://www.warwickhughes.com/climate/index.htm
http://www.john-daly.com/
If anything, climate science seems to reveal that the earth’s climate is dangerously chaotic even in the absence of anthropogenic effects.
The greenies are going to be pretty upset when, in the long run, this produces more rather than fewer efforts to manipulate climate.
Yes, the climate changes. Climate is statistical weather. Yes, the climate is mathematically chaotic. After all, the weather is a dynamic system where a handful of rules apply. Our sun is a variable star. I cannot emphasize that point enough! I am not aware of any models that include solar variability. I do know that as stars age, their output increases. Sunspots increase the amount of radiation reaching us when the magnetic loops associated with them result in flares that contain massive amounts of charged particles. We get even more energy when these flares interact with our planet’s magnetosphere. The result is a direct warming of the atmosphere.
Sunspot activity is cyclical also. The Little Ice Age that ended just a little over 100 years ago marked the end of a 400 to 500 year period of minimal sunspot activity, which is known as the Maunder Minimum. Lest anyone forget, the Medieval Warm period preceeding it featured very warm temps, warmer than today! This might be apocryphal, but I believe that it has been said that orange trees grew as far north as Memphis in the past. They don’t now.
One thing that I find overlooked is that C02 solubility in water. Warmer waters hold less C02 than colder waters. I cannot remember the figures off hand, but the amount of C02 in the oceans is several times more than that in the atmosphere. Warmer sea temperatures can result in increased biomass C02 production. We also know that volcanoes vent large amounts of C02, S02, dust, halogens, and water. There are volcanoes in Antartica, and we know that some are active.
I also remember reading a paper in Science magazine many years ago. The point was that the rain forest coverage of land during the last Ice Age was about 10% of the coverage today.
How does this explain the concurrent shrinkage of the Martian polar cap? Global warming part two.
Now explain to me why creationists are being dishonest pushing intelligent design when diploma carrying scientist ignor their own ‘scientific’ methodology to push their own political agendas?
It seems that if Earth’s temperature fluctuations match Mars’, then that would rule out a human or Earth-centric source for climate change. How much proof for-or-against is there for a correlation between Earth and Mars temperature?
I look forward to the Danes farming on Greenland again.
Here is what the serious climatologists have to say about it:
http://www.realclimate.org/index.php?p=221
“the scientific-media-political complex…”
WTH is that supposed to mean?
The Sanity Inspector,
Its the same as the military-industrial-political complex where the institutional imperatives of the military, the economic imperatives of defense corporations, and politicians using military spending as pork, all combine to distort defense spending and priorities.
In this case, we have the media which likes drama because it sells, scientist looking for grants and prominence and politicians looking to expand stand power (and thus their own influence) all combine to sell the same story of catastrophic anthrogenic global warming.
The same thing happened during the 70’s when a shortage of petroleum caused by government interference in the markets morphed into a global shortage of all “energy” that was portrayed as permanent and unquestionable. Politicians, scientist, academics and the media all climbed on board. Anybody who argued that the “energy crises” was just a political fabrication (like Milton Friedman) were laughed at.
Well said, Shannon. Hysteria has its own purposes and truth is not among them. And with climate change, we’re not talking ordinary and familiar scientific problems like “rocket science,” which requires newtoniain physics and engineering certainties. Climate is a dynamic, coupled interactive system of much much greater complexity, more comparable to the national economy – yet even that is better observed, recorded, and understood.
Recently, Roger Pielke, Jr., a climatologist at Colorado State University asked the proponents and critics of The Hockey Stick – the 1998 graph showing that the 90s are the warmest decade in the past 1,000 years – to explain the debates significance
here. Critics (see http://www.climateaudit.org) Stephen MacIntyre here,
and Ross McKitrick responded,, while proponent Michael Mann (www.realclimate.org) declined.
One wonders why not?
German climatologist Hans von Storch ventures an opinion here. “One or two years ago it was hard to publish results which were inconsistent with the [hockey stick] MBH reconstruction; now everybody agrees that there may be more to it. The jury is still out and I expect that consensus will settle on something with significant larger variations in the shaft of the hockeystick.
“Having said this – the debate about the hockeystick is most significant when it comes to the culture of our science.” Big egos and ‘good’ political have driven the results so far. “Have we, as a community, become better in rejecting such claims? I am afraid, we have not.”
Not inconsistent with Shannon’s opinion, von Storch is skeptical of scientists’ capacity to police themselves.
Your contention of a “weak correlation” between CO2 and average temperatures is not corroberated by the web site mentioned by S. King above, where they show a detailed graph as well as say “the results demonstrate clearly that the relationship between climate and CO2 that had been deduced from the Vostok core appears remarkably robust.”
I’m curious what you think of that.
Einzige,
We have something of a classic chicken-and-egg problem in figuring out whether greenhouse gas (GHG) levels drive the cooling and warming associated with ice ages or whether changing temperatures alter the levels of the gasses. A warmer planet will have more GHGs in its atmosphere than a cooler one due to basic chemistry even if the GHG have no significant contribution to the temperature level itself. For example, if all major temperature change was driven completely by insolation, the GHG levels would rise and fall in trailing sync with the temperatures. If you could not measure insolation but only GHG levels, you might easily conclude that the changes in GHG were driving the change in temperature.
There exist about a 600-800 year lag in the end of ice ages and the rises in levels of GHGs. An even longer lag in the decrease in greenhouse gasses occurs at the start of some ice ages. Clearly, GHGs do not drive major temperature trends but merely amplify trends begun by other factors. It is the degree of amplification that is under question.
The weak correlation I mention is not between temperature and GHG levels (which is strong but largely irrelevant) but between GHG level change followed by temperature change. There is a stronger correlation between temperature change followed by GHG change than the other way around.
Some researchers believe that the cores confirm their computer models but the models were designed to fit the data curves of earlier ice core samples. Simplistically, the models may have just copied the shape of the general curves themselves without accurately modeling the actual natural forces involved. This kind of problem shows up in computer modeling all the time. For any data set, there are a large number of possible models which will generate that data set. In order to really test the model, you must use it to predict a data set that wasn’t used in the creation of the model in the first place. I don’t think this was done in this case.
I don’t think the ice cores tell us much about global warming one way or the other. The time frames we are worried about are on the order of 100 years or less. The ice cores can’t even resolve a time span that small. Its quite possible that a C02 levels briefly reached the levels we have now but were not captured in the ice. More importantly, the temperature swings associated with ice ages are massive and clearly driven by some powerful non-atmospheric factor. They really don’t tell how much extra-heating we could cause by pushing already high C02 levels (compared to what they were at the end of the ice age) a bit higher.
Absolutely spot on. I could not have put it better myself.