Fact and Theory and Global Warming

Fact is that there aren’t many facts. But the difference between theory and fact is crucial in science and crucial to informed citizens who need to make crucial choices – some of which are based on fact and some on scientific theory. It is a theory – not a fact – that the recently observed speed-up of global warming is caused by human activity.  There is evidence for it but not proof.  That’s why it’s a theory and not a fact.

“Theory” is not an epithet.  We often must take action based on theory because it will be too late to act if we wait – possibly forever – for facts to be available.  I think global warming is one of those cases.  But it’s still crucial that we know the difference between fact and theory.

Scientists have believed for over a hundred years that the earth has been warming since a time twelve thousand years ago when much more of its surface was covered by glaciers.  (Before that, they thought that climate, geography, and species were all in steady states since creation  - that was the scientific consensus).

Recently, there has been evidence that the rate of warming is increasing.  Quite properly, many scientists were at first skeptical of this evidence.  Scientists are supposed to be skeptical.  They asked if warming was occurring everywhere or just in the places we happen to measure.  Good question since cities cause local warming without affecting global climate significantly.  They asked whether the variability was in the normal range of climate ups and downs or represented some sort of trend.  They asked if instrumentation could have changed.  Sure, some who asked these questions might have had impure motives.  But it was right, it was important to ask the questions.

The answer SEEMS to be that there has been a significant speedup of warming over the last century with real acceleration in the last couple of decades.  Doesn’t prove that this is a trend that will persist but is part of the evidence we need when considering action.  The case for action is stronger, not weaker, because the skeptics asked their questions.

In a thoughtful comment, Reader Paul S, who identifies himself as a chemist and a technical writer, takes me to task for not embracing whole-heartedly what he calls a “consensus” on global warming:

“Yes, it is always possible that the consensus could be wrong. It could be wrong in at least three ways: It might be that anthropogenic (human-caused) global warming is a complete myth. Or it might be real, but less severe than predicted. Or it might be more severe than predicted. Of these, only the first will reward us for doing nothing, and currently it appears to be the least likely possibility.”

Actually, the consensus could be right that global warming is anthropogenic and WRONG that we can do anything about it.  We could be past the tipping point.  That’s not an excuse for not acting but a very good reason to be skeptical that we’ll get the results we expect.

There is a form of very bad logic called post hoc ergo proctor hoc – Latin for the bad assumption that if A happens before B that A must have caused B.  We don’t know that the recent rise in carbon dioxide levels caused the recent warming.  There are good theories on how this could have happened but also good evidence that increased carbon dioxide levels are a CONSEQUENCE of warming.  Melting tundra releases carbon dioxide, for example.  There are also other greenhouses gases like methane, which come from cows, trees, and many other sources.

The anthropogenic theory does NOT explain why there were apparently other periods of very rapid warming before man got his hands on fire.  The evidence for these is strong.  The evidence that those warming spurts like the current one were accompanied by high concentrations of carbon dioxide is strong.  But the existence of these other spurts proves that there are other possible causes for global warming than human activity.  Perhaps the current spurt is also caused by something we don’t know about.  Hmmm….

Scientists, like all the rest of us, are affected by peer pressure.  The scientists who were skeptical of the fact of global warming are reviled rather than praised for their helpful skepticism.  It is dangerous to an academic career to say that the causal link between human activity and global warming is theory, not fact – almost as bad as admitting to having voted for theBushAdministration.  Because we know that political correctness works on scientists as well as ordinary mortals, the apparent growing consensus on an anthropogenic cause for global warming is suspect – not necessarily wrong, just suspect.

Paul S. also says:

“You do advocate taking steps, but you seem reluctant and hesitant. In the end, I think it's like any other case of taking precautions to avoid a disaster - boarding up windows when a hurricane threatens, or setting aside supplies for an earthquake.”

I am “reluctant and hesitant.”  That’s because the steps are very expensive, could be ineffectual or even have perverse results, and because “the consensus” is a theory which has not stood the test of much time or even reputable criticism.

Actually, I’m not hesitant about some steps like a return to nuclear power, increased use of wind, and solar because I think they are good ideas anyway.  I am hesitant about many proposed ethanol solution, huge subsidies or penalties, radical conservation aka the Luddites were right, and even carbon sequestration which is a great idea if there really is too much carbon dioxide but a waste of capital and energy if there is not.

We can’t hesitate to act in some of these ways.  We also can’t lose sight of the fact that we are acting on theory, not fact.  This means that we constantly try to DISPROVE the conventional wisdom; that’s the way science works.  We keep our skepticism.  We remain ready to change our actions if they prove either unnecessary or ineffectual (or counter productive).  Things could be worse than we think.  Maybe fast global warming is irreversible for the next five centuries whether it’s our fault or not.  In that case the priority is evacuating coastal areas, not reducing carbon dioxide emissions.

Comments

[Terry Oldberg]

While anthropogenic global warming (AGM) is an example of a theory, is not an example of a scientific theory. This is clear from a posting by a prominent climatologist.

The basis for belief in AGW is the set of climate models that are referenced by the United Nations Intergovernmental Panel on Climate Change (IPCC). According to the climatologist Kevin Trenberth ("http://blogs.nature.com/climatefeedback/recent_contributors/kevin_trenberth/"), the IPCC models do not make predictions. It follows that: a) the IPCC models are not falsifiable and b) the IPCC models are not scientific, by the definition of "scientific."

Belief in the proposition that the models are scientific seems to result from confusion of a model built by scientists with a scientific model. The mark of a scientific model is not that it is built by scientists but rather that it is falsifiable.

[J. Stewart]

Hello,

My name is Janet Stewart from CBC news. I would like to inquire about the facts and theory of global warming, and am interested in interviewing you for a program due to be airing on CBC in the late fall next year. Let me know what you think.

Regards,
Janet Stewart

[Ben Dover]

I think global warming is a good thing because I like the summer time a whole lot better.

[PuddleDuck]

Funny, isn't it, how people try to disprove global warming or evolution, by saying that it is "only a theory" as if it is based on a hunch or guess?

In scientific usage, a theory does not mean an unsubstantiated guess or hunch, as it can in everyday speech. A theory is a logically self-consistent model or framework for describing the behavior of a related set of natural or social phenomena. It originates from or is supported by experimental evidence (see scientific method). In this sense, a theory is a systematic and formalized expression of all previous observations which is predictive, logical and testable. In principle, scientific theories are always tentative, and subject to corrections or inclusion in a yet wider theory. Commonly, a large number of more specific hypotheses may be logically bound together by just one or two theories. As a general rule for use of the term, theories tend to deal with much broader sets of universals than do hypotheses, which ordinarily deal with much more specific sets of phenomena or specific applications of a theory.

http://en.wikipedia.org/wiki/Scientific_theory#Science

[Joe Nomak]

You talk about other times when the climate was warming due to CO2 and say maybe this is just another one of those times. You say we don't know why it happened. I believe scientist do know why it happened. Its the cyclical nature of our planet and ice ages. What is different now is that CO2 is at 375ppm. During the past 250,000 years and 7 ice ages it never passed 300ppm. Also ice is melting now that never melted before in the past 250,000 years. We can tell this with core samples. I think before writing on this subject you should study more data.

[Joe Nomak]

You talk about other times when the climate was warming due to CO2 and say maybe this is just another one of those times. You say we don't know why it happened. I believe scientist do know why it happened. Its the cyclical nature of our planet and ice ages. What is different now is that CO2 is at 375ppm. During the past 250,000 years and 7 ice ages it never passed 300ppm. Also ice is melting now that never melted before in the past 250,000 years. We can tell this with core samples. I think before writing on this subject you should study more data.

[ROBERT MACELVAIN]

Start watching for headlines that are more optimistic, such as these:

GLOBAL WARMING REVERSED!
DIASTER AVERTED... EARTH SAVED!
MAN-MADE CLIMATE CHANGES... PERMANENTLY NULLIFIED!

Albert Einstein provided the perfect scientific answer to Global Warming in 1905 with his paradigm, mass-to-energy equation, which is the key to unlocking all of the clean, cheap, environmentally friendly energy the inhabitants of Earth will ever need, without any pollution or waste stream, and with no carbon dioxide or other greenhouse emissions.

Even the super-powerful Energy Cartel will be unable to prevent millions of individuals around the World from freely switching to this abundant and everlasting Einsteinian cornucopia of "home-made energy," which will automatically reestablish Mother Nature as the exclusive controller of climate change.

http://slow-motion-Thermonuclear.blogspot.com/2006/06/invention-for-sale-slow-motion.html

[Russell Johnston]

There is another theory, and it fits the facts surprisingly well. I've discussed it as part of an article I wrote on Occam's Razor at logictutorial.com

Worse, the data shows anomolalies and looks quite different than it "should" if you look at the actual graphs of warming trends - industrialization is still a very good guess - but it remains a guess.

[Rajesh Raut]

Was Hurricane Katrina caused by human intervention? Should we not build levees around New Orleans because the flooding isn't anthropogenic? Humans constantly intervene to alter the natural environment.
The level of carbon dioxide in the atmosphere is rising. There is almost no scientific evidence that this is caused by human industrialization, though several other possible causes seem to be discounted. But that is not sufficient reason to not take steps to explore the science, technology, and policy that may be required to counter-act the current trend.
We need more research into measuring the effect that human activity has on the emission and absorbtion of carbon. You talk about skepticism but then blindly state that the steps will be expensive. They will certainly be expensive if we allow the Luddite anti-business lobby to dictate the terms of the debate.