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—an hir series—
and Investigative Research; 9 June 2014; by Francisco Gil-White
A brief introduction plus table of contents for this HIR series, which discusses why the Antarctic ice-core evidence is so important to a proper evaluation of the anthropogenic global warming (AGW) hypothesis, which holds that human production of CO2 is responsible for current global warming.
Once upon a time, for millions of years, and without any help from Man, planet Earth fluctuated between warmer and colder extremes. But in recent years many have been arguing that current global warming is ‘anthropogenic,’ which is to say a consequence of human activity. This is the anthropogenic global warming (AGW) hypothesis.
AGW is held to happen through the ‘greenhouse effect’: CO2 traps solar radiation and thus contributes to heat the planet; since humans produce some CO2, goes the argument, we are to blame for current rising temperatures.
Al Gore’s famous movie An Inconvenient Truth has dramatized IPCC reports and policy recommendations. According to the IPCC (the UN’s Intergovernmental Panel on Climate Change), a large-scale catastrophe will soon be upon us unless we make profound changes—on an emergency basis—in the economic arrangements that govern the lives of billions of people around the globe. A better standard of living for the world’s poor will have to be sacrificed, but the planet, warns Al Gore, “has a fever” (and prolonged fevers, if untreated, kill the patient).
Many are impressed by the fact that the IPCC (and Al Gore) received a Nobel Prize for making this argument. What many don’t realize is that this was a Nobel Peace Prize, not a science prize. The Nobel committee was praising the purportedly ethical effort of Al Gore and IPCC scientists.
Obviously, any discussion of political and economic reforms raises ethical questions. But matters must be stated in their proper order: this is first a scientific question. Why? Because the ethics of policies designed to alter global warming cannot sensibly be discussed until after the facts of Nature are properly understood. The policies recommended by Al Gore and the IPCC—which gained prestige thanks to the Nobel committee—will impoverish people everywhere. If there is no good reason for that, will such reforms be ethical?
I point this out because many now confuse a defense of the AGW hypothesis with being a ‘good person.’ This is nonsense. To defend or criticize the AGW hypothesis is to engage in a scientific debate.
Now, to get a better handle on the AGW hypothesis, allow me a metaphor. Imagine a feather coming gently to rest on the gas pedal of a car, after which the car shoots forward suddenly at 100 miles per hour. That’s a very sensitive gas pedal. The AGW hypothesis says that the planetary temperature’s sensitivity to greenhouse gases is a bit like this.
Why do I say this? Two reasons.
First, even if you think that the ‘greenhouse effect’ is very important to global temperatures, everybody agrees that CO2 in particular is a weak ‘greenhouse gas’ (see Figure 1 and Figure 2).
Second, in relative terms, humans produce small quantities of CO2. In fact, nature produces 33 times more CO2 than does human burning of fossil fuels (see Figure 3). And perhaps Nature produces a lot more than that, because undersea supervolcano production of CO2 is difficult to estimate.
So the AGW hypothesis is saying that a tiny increment (the quantity we add) of a relatively unimportant greenhouse gas (CO2) has pushed the planet off balance and induced runaway global warming.
We may find this plausible or implausible. But what really matters, in the end, is what the evidence says. Does it support AGW?
The mainstream Western media (whose behavior we examine in Part 4 and Part 5) has convinced many that the controversy has been settled—in favor of AGW. They also claim that virtually every scientist in the world agrees. This is false. A great many scientists dispute the hypothesis, but they have been attacked as ‘heretics’ and ‘deniers’—which is worrisome, because such name-calling is usually reserved for those who disagree with a religious dogma rather than with a scientific hypothesis. Is climate science becoming a religion?
Science institutionalizes doubt. Those who question the AGW hypothesis are therefore defending science. True scientists, regardless of what they believe, will celebrate rather than condemn that the possibility of Man-made global warming should be received with skepticism. And they will delight in the debate, gladly meeting their intellectual opponents to discuss their objections. For only when we allow—in fact promote—an open and vigorous debate can errors be identified and their sources corrected.
If proponents of the AGW hypothesis wish to find the truth, then they have nothing to fear—and nothing to lose!—from an open debate.
Laypeople should not be afraid to join this debate and come to their own conclusions. First, because the outcome of this debate will greatly affect them. Second, because even if conducting the science itself requires great technical expertise, understanding the findings and their relationship to the arguments does not. And the findings, moreover, are not in dispute.
Now, the most fundamental assumption of the AGW hypothesis is that even tiny changes in CO2 concentrations play an important role producing major shifts in planetary temperatures. If this turns out to be false, the entire argument collapses. For in this case human production of CO2 cannot be responsible for current global warming.
The gravest challenge to this most fundamental assumption of the AGW hypothesis comes from the Antarctic ice-cores. Many climate scientists believe that this key evidence in fact refutes the AGW hypothesis. And this alone requires partisans of the hypothesis to produce a satisfactory answer to the ice-core challenge. As we shall see, they have yet to do this.
What are the Antarctic ice cores?
Retrieving ice cores in the Antarctic (left);
Snowfall over areas of the Antarctic where nothing ever melts has created a kind of ‘fossil’ record of past atmospheres. As snow falls it traps air bubbles, and so layer upon layer of snowfall has created over time a vertical archive of bubbles going back 650,000 years.
Heroic geoscientists have drilled deep into the Antarctic ice to retrieve long ice cores. Later, in the lab, they extract air bubbles from the successive layers. By examining the composition of the air bubbles they can reconstruct the history of changing CO2 concentrations and also the history of changing temperatures (inferred from certain ‘isotopes’).
The Antarctic ice cores offer a natural test of the most fundamental assumption of the AGW hypothesis: do changes in CO2 concentrations matter to changes in the overall temperature?
If the ice core record shows evidence consistent with a causal relationship where CO2 ‘drives’ (i.e. causes) global temperature, then it is possible for the anthropogenic hypothesis to be correct (though it would still be necessary to show that human production of CO2 is sufficient to produce current warming trends). But if such evidence is missing, then the anthropogenic hypothesis will be dealt a severe blow.
As it turns out, the Antarctic ice-core record has produced zero evidence consistent with the view that changes in CO2 concentrations are responsible for major changes in planetary temperatures. Quite to the contrary, the ice-core evidence suggests that CO2 concentrations are a consequence of temperature changes, not the cause.
Does that make sense? It does. Basic chemistry: CO2 is more soluble in cold than in warm water. When something else warms the planet, the oceans release CO2.
The Antarctic ice-core results should have forced a very public debate on the merits of the AGW hypothesis. Instead, defenders of this hypothesis have rather brazenly claimed that the ice-core evidence is somehow the best evidence in their favor. And they have insisted, for good measure, that their view is “settled fact.”
This perfect inversion of the truth was, in fact, the climax of Al Gore’s film, with Gore posing in front of a gigantic representation of the Antarctic ice-core evidence and laughing off as “ridiculous” that anybody should doubt that this evidence proves him right.
That was bold. Perhaps that’s why it worked.
An Inconvenient Truth. Al Gore: “when there is more carbon dioxide, the temperature gets warmer.” The backdrop is a double graph of the Antarctic ice-core evidence, which in fact shows the opposite.
Why are defenders of the AGW hypothesis inverting the truth of the Antarctic ice-core evidence?
That is an important question. But before it can be addressed, we must be clear on what can and cannot be claimed concerning the state of the art of our scientific knowledge. In this series, we will explain what the ice-core evidence is, why it is so important, and why it does not help the AGW hypothesis.
Happily, there is no disagreement about the quality of this evidence, or about what it says. Also happily, this is all quite easy to understand. The lay reader, therefore, once the evidence is explained, will be in a position to make up his or her own mind.
Below you will find a table of contents for the entire series.
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