Damned if you do, damned if you don\'t

Via Sploid, here's a BBC story about how plants cause global warming. Ok, ok, not all by themselves. But plants are now thought to be a significant source of methane emissions. Add to this the story I heard on NPR a few weeks ago. (Call me a statist now if you like.) Some pollutants that reside in the upper atmosphere absorb sunlight, so reducing their emission will increase global temperatures.

Thinking on global warming is already muddled enough. The pursuit of scientific knowledge is always a worthy pursuit; prematurely basing bad policy in conflicting results—that ought to wait.

Share this

Obviously the solution, if

Obviously the solution, if we want to save the planet, is to burn down those nasty methane polluting rainforests.

Methane, though, is highly

Methane, though, is highly volatile and clears the atmosphere within 300 years. That is, for any given amount of methane injected into the atmo, it will be completely chemically transformed/stored/destroyed within 3 centuries. Carbon Dioxide has a far longer residence time in the atmosphere, so even though methane is a far greater greenhouse gas than CO2, it is a (geologically speaking) very short term and marginal component. Also, human action will tend to *burn and eliminate* methane since it's a source of hydrogen, rather than add more to the environment.

Thus I'm not sure how big a deal methane production by plants is- one would have to assume that since the amazon was in existence even during the glacial period (presumably pumping out loads of methane as today) that we can cancel out plant contributions as being part of the baseline, rather than a source of net GHG increase.

I heard this on NPR this

I heard this on NPR this morning (not a complete statist - I pay $$$ for it, which I don't do for any other radio show, so maybe not completely rational, either). The biggest error I heard was that the reporter called CO2 "the most important greenhouse gas." No, that would be water vapor. As I recall, methane has a very strong mid-IR absorption band, but it's so much less abundant in the atmosphere that it is less significant than CO2, but they both pale compared to water. At least in the next story, they got the part right about global warming causing night temperatures to be lower and day, greater. Let's see if they remember that when they start reporting the daytime highs this summer.

I immediately thought about the grief Reagan took over pointing out that trees contribute to pollution, too. Turns out he was right: he was citing a report that described the amount of VOCs emitted by trees.

One interesting possibility from this finding: if you could identify the methane expiration mechanism and use that knowledge to selectively breed plants that don't expire as much, then, in a climate richer in CO2 and therefore with less water transpiration, you might be able to grow larger, more nutritious plants with no additional or perhaps fewer resources. Is that cool or what?

Also, what other major discoveries would completely undo the Kyoto calculations as this may?

Eric, To slightly come to


To slightly come to NPR's defense, CO2 is the most important GHG (in human terms) because it is relatively chemically stable in the atmosphere for long periods of time, and geologically speaking CO2 seems to be the prime mover for maintaining temperature.

Water vapor can come and go in the blink of an eye- it can fall out as rain or enter via evaporation. Obviously water vapor amounts are going to be driven by other factors, so even though H20 is the bulk of the greenhouse effect, the marginal factors that drive water vapor changes are going to be more important.

As far as plant breeding goes, its generally unnecessary to get the results you want- increased CO2 levels simultaneously increase drought resistance and spike photosynthetic productivity in plants already. It is that reason, among others, that the net CO2 increase is less than a 1:1 from anthropogenic sources, since there is a positive feedback on carbon fixation from rising CO2 levels.

Correct me if I'm wrong, but

Correct me if I'm wrong, but isn't CO2 already at such a concentration that it absorbs virtually all the outgoing IR at its wave length? That's why you have to build an amplifier into your atmospheric model to make it predict that further CO2 emissions will have much effect.

It was believed for a long

It was believed for a long time that the bernoulli effect, through changes in air pressure at the top of a wing due to the air moving faster over the top part caused lift, which allowed airplanes to fly. But recently evidence has surfaced that shows that the bernoulli effect was not what was causing lift, and that in fact the theory was wrong in important ways.

Thank god people didn't act on the basis of what turned out to be incomplete scientific information. I would really hate for decisions to be made when all the facts aren't in; prematurely basing decisions on bad results -- that ought to wait.

Kind of a stretch, Dave.

Kind of a stretch, Dave. Flying on incomplete knowledge still successfully gets off the ground, and it's a negligible social cost for everyone else. A "global warming plan" may or may not work (and we probably wouldn't know anyway) and imposes massive costs on people all over.