An inconvenient argument

Inconvenient Truth posterOld ice reveals information about atmospheric conditions that prevailed when it was formed, and it shows rises in atmospheric carbon-dioxide levels lagging rises in global temperatures. That is, historically, the earth’s temperatures went up first, then CO2 concentrations followed.

For some, this is evidence that the idea of human-induced climate change is a fraud, and their case is strengthened by the fact that the graph everyone remembers from An Inconvenient Truth is the one where Al Gore uses a mechanical lift to show what’s happened to CO2 concentrations since the industrial age began.

Some skeptics use this fact — and it is a fact — to dismiss the whole idea of atmospheric global warming. The syllogism goes like this:

  • Climate-change fearmongers say atmospheric carbon dioxide contributes to climate change
  • Things other than human influence have previously increased the level of carbon dioxide in the atmosphere
  • Therefore, the science of climate change is bunk.

Blogger “Reasic” has a learned post today explaining why this argument is nonsensical not just on logical principles, but citing specific facts. Scientists haven’t just looked a little cross-eyed at what happened in the past, seen what’s happening now, and sounded the alarm.

The Milankovitch Cycles [changes in the earth’s orbit and physical attitude toward the sun] are known to be the catalyst for sending our planet into and out of ice ages. These cycles are also considered to be too weak to cause the entire amount of warming that occurs between glacial and interglacial periods. It is understood that, once warming starts around Antarctica and CO2 is released, a positive feedback is started – as temperature increases, CO2 increases, which increases temperature again, etc. This continues in increasingly smaller increments until equilibrium is reached.

Nobody respectable is seriously arguing that climate change is due entirely to human activity — of course there are natural cycles and we’re in one now. The concern is that we’ll exaggerate the natural effect by emitting extra gases into the atmosphere, possibly irreversibly (at least until the next ice age comes upon us, which is a matter of millennia, not decades).

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5 responses to “An inconvenient argument

  1. I agree that its a concern, but believe the climate change debate occupies way to much media mindspace, when there are other ways we are toxic to the environment that now are being overlooked: http://hrmnk.wordpress.com/2007/05/08/global-warming-debate-misplaced/

  2. On the one hand, there’s immediacy and visibility; on the other, potentially extreme — not just bad, extreme — consequences. A classic competition for attention.

    It definitely seems to me that concern about climate change is slopping over into attention into a lot of other environmental issues, though, and it doesn’t always have to be either-or. Plastic bags are a petroleum product we don’t need to use as many of as we do, and if we cut back on them for greenhouse-gas-related reasons, we save on landfills and environmental toxins, too.

  3. David,

    I just wanted to say “thank you” for the link. I had heard or seen that argument several times, so this time I decided to devote a post to it. It’s such an illogical argument, and yet it’s used by so many, including some supposedly very knowledgeable people (Harvard physicist Lubos Motl, for example).

  4. I’d be ecstatic if the climate change issue would expand into local ones.. but to my dismay more people are considering nuclear energy, minimizing the waste associated with it, to reduce greenhouse gases.

    The actual should trump the potential problems, in my opinion.

  5. Well done you and Reasic, I find it amazing how the majority of vocalising is coming from across the pond. The UK seems to be in denial as to the climate and the government is ordering greenwash by the tanker load! My blog directed me to yours and hooray for technology. Keep up the pressure. I await the thaw in the Antarctic observations this year and wonder how any huge ice breaks will be explained as “Natural Events”
    Brian

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