Saturday, February 27, 2010
...net photosynthesis increases as CO2 levels increase from 340 to 1,000 ppm (parts per million). Most crops show that for any given level of photosynthetically active radiation (PAR), increasing the CO2 level to 1,000 ppm will increase the photosynthesis by about 50% over ambient CO2 levels... For others such as tulips, and Easter lilies, no response has been observed.To be fair though the article's text says increasing by 1,000 ppm would double plant growth this accompanying graph only shows about a 20% rise. My guess is that either the graph has been corrected to fit political correctness or that the graph, but not the text, refers to the more limited growth opportunities under Canadian sunlight.
Carbon dioxide enters into the plant through the stomatal openings by the process of diffusion. Stomata are specialized cells located mainly on the underside of the leaves in the epidermal layer. The cells open and close allowing gas exchange to occur. The concentration of CO2 outside the leaf strongly influences the rate of CO2 uptake by the plant. The higher the CO2 concentration outside the leaf, the greater the uptake of CO2 by the plant. Light levels, leaf and ambient air temperatures, relative humidity, water stress and the CO2 and oxygen (O2) concentration in the air and the leaf, are many of the key factors that determine the opening and closing of the stomata.
Ambient CO2 level in outside air is about 340 ppm by volume. All plants grow well at this level but as CO2 levels are raised by 1,000 ppm photosynthesis increases proportionately resulting in more sugars and carbohydrates available for plant growth.
However even if we take the graph it shows an increase to 450 ppm (the amount the alarmists claim to be really worried about) would increase plant growth by about 8% further.
Which explains why the Sahara is shrinking.
Which would mean an 8% increase in crops worldwide with no other action from us. So instead of feeding the world's 6.7 billion we could feed another 530 million.
So the downside of "Catastrophic Anthropogenic Global Warming" is ----
That it won't happen. "The amount of carbon dioxide emitted from human sources is small in comparison to natural flows:at around 3% emitted from the land and oceans to the atmosphere" according to a government Parliamentary answer given to John Redwood. This means that even if the amount of CO2 in the atmosphere went up as little as an extra 40 parts per million the amount extracted would 3% matching all that humanity puts in. We have a very clear negative feedback system in operation.
If the rise in CO2 is caused by humanity, which is an open question but one on which the alarmist case entirely hangs & which they claim is "settled" then that rise, with all its alleged effects, is self limiting.
So we aren't going to have significant warming; nor more food production without working for it; nor vineyards in Scotland; nor the Antarctic becoming a "habitable continent".