Sunday, January 4, 2009

Is the Global Warming Theory Falsifiable?

One of the marks of science is falsifiability. If a theory cannot be proven false, it is not scientific. It is incumbent upon the advocates of the theory that the earth is warming to define how their theory can be proven false. If it cannot, it is not a scientific theory. I watched the Al Gore video and do not recall him mentioning how his theory could be proven false.

Bob Robbins just forwarded this from the Astute Blogger. The Astute Blogger quotes a number of articles suggesting that this winter is colder than usual in several places, including Wales, India, Sri Lanka and Alaska.

Global warming theorists might reply that the fact that there are swings in temperature is indeed evidence of global warming. If that is so but the swings in temperature fail to reject the null hypothesis of greater variability (this would involve an F test)then the theory of global warming is rejected. Otherwise, I am having trouble understanding how cooler temperatures in various countries can be consistent with "global" warming.

>FUNERAL directors in Swansea have revealed they are holding more services than usual following a rise in deaths.

They say there has been an increase in the death rate and Assembly-based health experts confirmed the freezing temperatures could be responsible.

... Latest provisional figures for winter 2007/08 reveal there were around 1,500 excess deaths in Wales — a seven per cent rise on the previous winter.

>At least 31 people have died in India's northern state of Uttar Pradesh as severe cold weather continues in the region.

>A severe cold wave is hitting the Nuwara Eliya district, thus affecting tea and other plantations in the low lying areas.

>Rapid growth spurt leaves amount of ice at levels seen 29 years ago.

Thanks to a rapid rebound in recent months, global sea ice levels now equal those seen 29 years ago, when the year 1979 also drew to a close.


Greg Goss said...

Getting Global Warming supporters to acknowledge these "facts" is like getting the people who blamed Bush for $4.00 a gallon gasoline to now thank him for $1.50 a gallon.

Thomas Esmond Knox said...

I think there should be a series of falsifiable statements of the "Global Warming" claim, ranging from "strong" to "weak".

"Strong" might be "Global Warming means that temperatures in every temperature station in the world show higher maximum and minimum temperatures than the same date last year."

BVanGerven said...

No, it isn’t.
The AGW theory is not falsifiable. Many perfectly valid scientific theories are not falsifiable, f.i. “Smoking increases the risk of getting lung cancer” is a statement that is not falsifiable, but I think few scientists – and ordinary people – will doubt that it is true.
A scientific theory is is generally accepted by the scientific community, not because it hasn’t been falsified, but because it explains and predicts very well the phenomena that occur.

Mitchell Langbert said...

Dear B Van Gerven: Thanks for your comment. You are incorrect that the claim that smoking causes cancer is not falsifiable. It certainly is. I suggest that you familiarize yourself with Karl Popper's "Logic of Scientific Discovery" to learn the meaning of the term "falsifiable". Peter Blau, the famous Columbia University sociologist of the 1950s-1980s introduced me to this concept when I took his sociological theorizing course in 1988, right before he retired.

You are expressing a common misconception of how science ought to work. A scientific theory doesn't necessarily predict phenomenon. For example, the astronomical theories of cosmology and cosmogony as well as archaeology and biology, anatomy and many other disciplines do not make predictions. Very little in the social sciences make predictions, specifically economics is incapable of making predictions.

Popper defines falsifiability as the use of evidence to contradict theory. That is, in fact, how science works.

In the case of smoking, falsifiability works like this. A scientist states the hypothesis that smoking causes cancer. Data is collected. The data show that smokers, controlling for all other determinable variables, die sooner, have higher rates of heart attacks and the like. This is consistent with the hypothesis.

Let us say that a study found that if one controls for sun spots, then the significance of the smoking factor disappears. That would falsify the smoking hypothesis. Smoking-causes-cancer theorists then have to show that the sunspot factor does not dominate the smoking factor.

Theories can never be proven, but they can be falisified by contradictory evidence. Laymen do not often understand this relationship of evidence to theory. There is no such thing in reality as a proven theory. You need to read David Hume thoroughly to understand why this is true philosophically. Kant tried to prove otherwise, but his proof is unconvincing.

No hypothesis ever is proven. As Thomas Kuhn shows in his classic "Structure of Scientific Revolutions" science moves to new paradigms not because of the absolute falsehood of the old paradigm but because of the old paradigm's inability to explain contradictions.

Knowledge in the layman's sense, the way that you conceive of science, is not possible beyond a certain point. Aristotle believed that appearances lead to knowledge, and he was right, in my opinion, with respect to human decision making. It becomes evident as you examine data in depth that it is extraordinarily hazardous to say anything with certainty. The scientific mind is a questioning mind.

As Popper points out, science depends on falsifiability because scientists must always be open to the possibility that they are wrong. In true science, contradictions inevitability appear as data is adduced. Theories lend order to observed data, but are never complete.

The claim that science is "settled" is inherently anti-scientific, as a reading of Popper and Kuhn will clearly show.

The scientific community's acceptance of theory is meaningful only to a point. Unless contradictions are being reconciled to the theory, then the risk of scientism and fanaticism appears.

This has occurred with respect to global warming theory. It is junk science.

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