The UnAustralian

Friday, July 11, 2003
 
Science Vs. Pseudoscience

It seems that this post really got Sylvain Galineau a bit worked up. So much that he's appears to be determined to publicly demonstrate his lack of knowledge about how science works (as if citing Ann Coulter as a scientific source isn't enough).

I would try and explain the difference between a observation and a theory here, but like most things in life, somebody has already done it far more eloquently than I ever could. Steven Jay Gould writes:

[F]acts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. And humans evolved from ape-like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered.

While Gould was talking about evolution and creationism, it is quite convenient for me that he mentioned some of the various theories of gravity.

So Sylvain, gravity is both a fact (or observation to be more precise) and a theory - don't go throwing yourself out a window just yet.

To expand on the gravity example, around the world, millions of dollars are being spent on research into a predicted but (as far as I know) never observed phenomena known as the gravity wave. Meanwhile early space probes are reporting back strange data, which is suggestive of gravity behaving differently at long distances than what the theories predict (however, it should also be noted that instrumental errors could be causing this). It is quite likely that our knowledge of gravity is incomplete, and the following decades should bring new surprises.

So now, back to our story, is global warming both a fact and a theory.

The answer, is of course unsurprising. Yes.

To start off, our observations suggest that the worlds surface is undergoing an overall warming trend. This has been confirmed by both ground based temperature readings, and satellite data.

Now, onto our theory. Greenhouse gases have been known for a very long time to warm the earth (in fact, it was Joseph Fourier in 1820 who started the whole thing - see here for a in-depth history from the American Institute of Physics*). It stands to reason, that if a certain quantity of greenhouse gases warm the earth by a certain degree, the addition of more greenhouse gases, will lead to more warming. This is a pretty simplified statement, and nowadays we use large complex models to try to get both qualitative and quantitative answers. Thus we have our (at least a very small subset of) observations and our theory.

Now the next step is to test it. Lets take an example which very few people would think of (and because I know how much Sylvain likes to bitch and moan about uncertainties, this one should allow plenty of whinging opportunities). How about isotope levels in the Amazon? Monitoring of isotope levels in the Amazon basin has been carried out for quite sometime now. This is because they give valuable information on what happens to the rainfall. Recently, the fate of precipitation in the Amazon has been changing. Low and behold, the changing weather patterns in the Amazon as determined by isotope levels, roughly match with global climate models (there are discrepancies, especially in the dry season, but as the authors state "[r]esults of GCM simulations of Amazonian deforestation suggest that the recent stable isotope record is more consistent with the predicted effects of greenhouse warming possibly combined with forest removal than with the predicted effects of deforestation alone"). (Source: Henderson-Sellers, McGuffie and Zhang; Stable isotopes as validation tools for global climate model predictions of the impact of Amazonian deforestation, Journal of Climate, Sept 15, 2002**).

Now, one of these days, I'll have to do what I originally wanted to do with this post, and explain what the difference between science and pseudoscience is.

* Apologies in advance to Sylvain for quoting a scientific body rather than Ann Coulter, next time I'll get off my pedestal.
** Damn it. I meant to get of my pedestal and look up Ann Coulters contribution to changes in isotopic abundances of oxygen and hydrogen in precipitation over the Amazon basin, but I just couldn't bring myself to do it. How elitist of me.
| 12:11 AM