OT: "The Amazing Randi", of all people, has swallowed the GW dogma:

John

You might invest an hour and review the history of evidence, opinion and propaganda on the subject.

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Regards,

John Popelish

Have a closer look at their graph:

I see a downward trend in sea ice. 2007 has the lowest point since the covered time period begins in 1979. According to my eyeballs, the average for 2007 was about 7.5-8% less sea ice than the 1979-2000 average, dipping as low as about 15% less.

The recent La Nina got sea ice up to a 7 year high.

- Don Klipstein ( snipped-for-privacy@misty.com)

It looks to me like the major function of CO2 is that it allows prople who don't design electronics, and who don't have much to say about electronics, to post to sci.electronics.design and pretend that they know stuff that other people don't.

John

What I see is that there is a little gang of AGW denialists among the major contributors to sci.electronics.design that produces plenty of banter and chatter in the OT political threads in this group related to AGW. One of that gang started this thread.

- Don Klipstein ( snipped-for-privacy@misty.com)

Why do plants have so many leaves? And why do they use such a tiny fraction of available solar energy?

John

And here I thought all the lambasting about GW was a reference to Bush.

Farmer

Maximum surface area.

They evolved to use only what they need. :-)

Hope This Helps! Rich

Because they weren't designed, but evolved. Once they got good enough there was little pressure to improve. Other problems are bigger for plants.

Besides, once plants evolved from absorbing only one wavelength to absorbing two, they became smug and self satisfied.

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Regards,

John Popelish

Not all of them do. A few cacti and some succulents are highly modified stems with no leaves at all. The most famous of the leafless plants is Lophophora Williamsii, better known in the USA as Peyote. A plant that you cannot legally grow in "the Land of the Free".

Limitation of the chemistry. C4 metabolism is about as good as it gets. Synthetic organic chemists have yet to equal chlorophylls performance and have the whole system remain stable for long enough to be useful. It doesn't stop them trying though.

A few pages from Chapter 1 of the definitive review of photosynthesis chemistry are online at:

Regards, Martin Brown

** Posted from **

Low utilization is probably for a reason similar to that for solar cells. There is a peak utilization wavelength, where photons have slightly more energy than some bandgap. Wavelengths much longer than that don't get utilized at all, due to photons having insufficient energy to push an electron from a lower energy level to a higher energy level. When the wavelength is shorter, photon energy in excess of that used to push an electron from lower energy level to higher energy level becomes heat. So a blue photon only gives a plant as much chemical energy as a red one, even though a blue photon has more energy than a red one.

Plants have their primary utilization peak around 660 nm (red peak of chlorophyll A). Accessory pigments and blue chlorophyll absorptions absorb wavelengths of a variety of shorter wavelengths and transfer the energy to the main chlorophyll A process. But most plants don't utilize green light well, because the chlorophylls and the main accessory pigments mainly utilize red and blue.

So wavelengths longer than about 700 nm (almost half of average daylight) don't get utilized, green wavelengths are not utilized well, and blue wavelengths are utilized but with some significant loss. UV is utilized less than blue is, and with even greater loss.

- Don Klipstein ( snipped-for-privacy@misty.com)

NEEP! The reason is that they only have about 350 PPM of CO2 to work with. Photosynthesis could be far more efficient, but under current conditions, it wouldn't help much.

John

Make that 380 now...

Meanwhile, plents grew well a century ago when CO2 concentration was

280. I am not hearing about everything growing 36% faster than a century ago. Looks like the limiting factor is usually something else.

- Don Klipstein ( snipped-for-privacy@misty.com)

Not so well. Crop yields are far better now than anything grown a century ago. We have selectively bred high-yield plants for the current CO2 levels; future, higher CO2 levels, and higher temperatures, will further improve yields. Not to suggest that one causes the other.

Why does the increase in CO2 levels have to be unreservedly bad?

The personality correlation is interesting: gloomy/leftist people tend to give a lot of weight to the worst-case predictions of AGW; cheerful/rightish people tend to be skeptical, or to assume we will cope.

John

Which is why I say we should make huge greenhouses around powerplants. Circulate a metric shitload of CO2 around the thing, like whole percents of it. Maybe even 50%, I don't know. (Probably too much is poisonous for any plant, and more than a few percent would be hazardous for people to walk inside -- but they'll only need to go in for the harvest, right?) Between old fashioned evolution and GM, we should be able to breed damned fast plants in just a few decades. Screw algae, this requires even less infrastructure (and hardly any pressure to pump the CO2).

Tim

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Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

It isn't all that difficult to know stuff that John Larkin doesn't, but it is remarkably difficult to educate him out of that condition, and - of course - it is pompous and ill-mannered to make the attempt.

-- Bill Sloman, Nijmegen

That is one way of looking at the situation. The alternative approach, that accepts that Al Gore has got it more or less right and anthropogenic global warming is real, is probably a bit more realistic, but when was Rich Grise last in contact with reality? Conspiracy theories are so much more entertaining.

-- Bill Sloman, Nijmegen

Excellent video. Thanks.