Thursday, December 29, 2011

C02 Not The Biggest Global Warming Culprit After All

My son has spent years lecturing me about the actual density of carbon dioxide, or CO2, in the atmosphere, and the overall effect such a small percentage can have on global warming.

And I, thinking I heard wiser (or at least older) voices, have ignored him.

Turns out he’s at least partly right. Carbon dioxide, by volume, represents less than 0.004 percent of earth’s atmosphere. Water vapor, on the other hand, represents 4.0 percent; both are greenhouse gases, or GHGs.

As are methane (0.00018 percent), nitrous oxide (0.00003 percent), ozone (0.000001 percent), and those nasty fluorocarbons (coolants and propellants, at 0.00000005 percent).

But he’s right for all the wrong reasons, because even though it’s clear that the density of a gas in the atmosphere is not a primary global warming trigger, it’s also evident that mankind’s activities for the last 100 years have made a significant difference in global weather patterns via the amount of CO2 released, primarily by burning fossil fuels (a release that remained negligible during all the years prior to the Industrial Revolution).

For example, even though the methane being released from thawing of the Arctic permafrost may be a much greater danger to climate stability than CO2 at this point, it is equally as clear that CO2 can’t be left out of any sensible equation. In fact, as resident expert Joe Romm points out  , “Methane is 25 times as potent a heat-trapping gas as CO2 over a 100 year time horizon, but 72 times as potent over 20 years  !”

His remark, taken out of context, would suggest that, in the short term, we should perhaps be more worried about methane than CO2. But it’s this kind of thinking – encouraged by studies like that from Oregon University   – that may lead us to recklessly exploit the ability of the planet to “bounce back” from CO2 burdens; a theorem expressed by study author Andreas Schmittner, who said, “Our study implies that we still have time to prevent (the worst of global warming) from happening, if we make a concerted effort to change course soon.”

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