Nathan Scandella (personal)

Climate Change Mythbusting (Part IV)

So, I was on Karl Denninger's blogsite today, the Market Ticker, where he was venturing out of his field of expertise (finance) to lecture the masses on climate change, and how much of a scam it is (as a scientific theory). As has happened before, Denninger censored me, by revoking my ability to make comments. Why he keeps letting me back, only to ban me again, I'm not sure. Perhaps I'm still approaching my third strike. Anyway, I will continue my point here. One of his ignoramus readers made the comment, in response to one of mine, that it didn't make sense to even be discussing CO2, because CO2 is a lagging indicator, with respect to temperature. This is a common false argument amongst the denial crowd, so I'll address it here.

Atmospheric CO2 concentration has, in fact, in the past lagged increases in global temperature. The implied denialist argument is that since this is the case, in the present, increased levels of CO2 cannot be causing temperature increases. False.

First of all, it's entirely possible for two independent metrics to positively affect one another. In other words, increases in A can cause increases in B, and increases in B can cause increases in A. It doesn't always work that way, but it can. So, it's simply erroneous to assume that since A seems to cause B, B cannot also cause A. Engineers refer to such a relationship as a positive, or unstable, feedback loop. For example, take dry grass in a hot field. In this case, excessive heat can cause fires to start, and once the fires have started, we know that fire produces excessive heat. This positive feedback loop is why fires in hot, dry environments tend to spread.

A logical response might be, "well, if CO2 and temperature really have a positive feedback relationship, why haven't past warming periods (pre-mankind) led to runaway levels of both CO2 and heat, with the earth ultimately cooking itself?". The reason is that the feedback relationship is not the only driving force in the system. In the case of wildfires, fires don't spread indefinitely, consuming the whole earth in flames. Ultimately, the feedback loop between heat and flame is broken by an external factor, such as

• the fire consumes all the fuel, whether that fuel is dry grass, forest, or whatever


• the fire is put out by water, either via heavy rain, human fire brigade intervention, or possibly the fire's extent reaching a non-flammable body of water


• if the fire is indoors, it can actually consume itself if oxygen becomes depleted

In the case of CO2, remember that before the industrial age, there were no major fossil fuel combustion processes, so the supply of non-atmospheric CO2 was constrained to other sources - for example, the CO2 absorbed in the world's oceans. But, this is a finite quantity. After a certain amount of warming, there is no more CO2 left to outgas from the oceans ... somewhat like the fire running out of grass to burn. In the past, temperature spikes may have been limited by the fact that no fossilized carbon was available to further amplify the warming process. So, the lack of a previous complete planetary meltdown is not enough evidence to discredit the notion that CO2 and temperature increases may positively affect one another (positive in the sense that more of one leads to more of the other).

Of course, fossil fuels are in finite supply, too. At some point, we'll stop being able to burn them. However, the sum total of all oceanic CO2, and all fossilized carbon, could certainly equal a total amount of CO2 never before seen in the earth's atmosphere, at the same time. Aside: the finite supply of fossil fuels is actually another great reason to wean ourselves off those fuel sources, before we run out. Choosing to switch to renewable fuels is less about choosing to switch (eventually, we'll have to), and more about when we decide to do so.

In situations where you do have two factors that affect one another in this way, what you will get is an extremely high mathematical correlation. And, what do you know? It just so happens that CO2 and temperature histories correlate very well.

As we all know, correlation does not necessarily mean causation, why is why the theory of Anthropogenic Global Warming is not solely dependent on the observation that CO2 and temperature levels have historically varied in unison. This point is critical!

Supplementing the correlation data, we also have both theory, and isolated experiments, that show that a layer of CO2 does in fact retain heat. The theory is based on the absorption of infrared radiation by gaseous CO2. This theory is easily verifiable in a laboratory (e.g. using a sealed chamber with CO2 inside, and an infrared heat source), and in fact, has been verified. This is not the part of climate change that's uncertain. The uncertainly comes in when estimating just how much a given amount of man-made CO2 will be retained in the atmosphere, how much "insulation" that gas provides, and how much the earth's climate will change in the future, based on only educated guesses as to how much CO2 we'll continue to produce going forward. And, then, there's the fact that climate change is not simply a result of anthropogenic CO2, but also a result of other factors. Nevertheless, it cannot reasonably be concluded that CO2 lagging temperature data in the past invalidates the entire hypothesis. That's faulty logic.

But, the idea that CO2 also yields temperature increases should not be controversial, and is in no way in conflict with the historically lagging relationship of CO2, with respect to temperature.

Posted at 12:14AM Nov 22, 2009 by Nathan in Environment  |  Comments[1]