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Pastimes : The New Qualcomm - write what you like thread. -- Ignore unavailable to you. Want to Upgrade?

To: Maurice Winn who wrote (7707)	11/20/2006 10:42:56 PM
From: A.J. Mullen	Read Replies (1) \| Respond to of 12246

Maurice, I'm glad that you now accept that CO2 isn't a panacea that increases growth rates at any time, that plants won't grow if they are limited by other nutrients. You say "of course" they have to be in situations where they aren't limited by something else"... That was my point, some while ago. In general plants are limited by other nutrients. That also seems to be the main point made in the links you provide. In the first link, the first page of paper by Kramer, the first sentence states "Many scientists seem to assume that an increase in CO2 .... increase global photosynthesis..." The last sentence of that first paragraph reads. "But are these assumptions valid?" We are unable to read the conclusion. The next link is an abstract which contains Our results indicate that the production of phytochemicals in the birch seedlings is very sensitive to both fertilization and CO2 addition, which is in agreement with earlier studies, and thus provide some support for the hypothesis of carbon allocation to plant defence when there is an excess of carbon and nutrient. And your final link contains another abstract: ...the effect of combined elevated CO2 and ultraviolet B (280320 nm) (UV-B) radiation allow no general conclusion. ..... Plant responses to elevated atmospheric CO2 and other environmental factors such as soil salinity and UV-B tend to be species-specific, .....Therefore, the effects of joint elevated atmospheric CO2 and increased soil salinity or elevated CO2 and enhanced UV-B to plants are physiologically complex. I'm frustrated because I realise that you accept that CO2 has increased since the industrial revolution. It's an increase of around 30% en.wikipedia.org. Clearly plants have not absorbed all the CO2 we've released.