Claim 4. Manmade CO2 levels have been rising rapidly due to increased industrialization and populations since the 1950s.
Truth: CO2 levels have been steadily rising along with warming since the Little Ice Age. Recent increases in industrialization and population appear to have contributed to the increase in atmospheric CO2 since the 1950s when fossil fuel consumption began increasing. Rising temperatures have also contributed to increased CO2 because it is less soluble in warmer ocean water and is thus released. it is unclear how much is from manmade sources and how much is from natural processes, but some estimate put it at 5%. However, if CO2 is not responsible for global warming, (see previous posts) increased levels shouldn’t alarm anyone and in fact increased CO2 should be celebrated as a plant growth promoter.
Claim 3. Carbon dioxide is important because it has a forcing effect on other factors such as water vapor which magnify warming effects.
Truth: Since the atmospheric absorption of CO2 is already near saturation, (see previous post), very little additional heating can take place due to increased CO2. Contrary to AGW advocates, increased water vapor from warming doesn’t stay as vapor to trap heat near the surface. It forms low altitude clouds that strongly reflect solar heat back out into space, overwhelming any trapped re-radiation from the Earth and having an overall cooling effect. The models, which assume water vapor remains as vapor, predict an atmospheric “hot spot” at middle altitudes. Weather balloons and satellites have failed to find this assumed hot spot, which is the signature of atmospheric forcing of global warming in computer models. Due to low altitude clouds reflecting sunlight back into space, any feedback is negative (cooling), not positive (warming) as assumed in computer models. For earlier posts, go to http:realscienceblog.com
a.) Animals exhale CO2 and breathe in O2, while plants use CO2 for photosynthesis and “exhale” O2. Professional greenhouses often add extra CO2 to increase growth rates. Increased plant growth removes much of the CO2 released into the atmosphere. Between pre-industrial and present times, studies show an average of 15 percent increase in plant growth rates, with some species increased many times that, e.g, young pine trees. Increased plant growth rates and wider distribution of arable (farmable) land due to warming as well as improved farming practices can solve the so-called overpopulation problem.
b.) Critics created the “progressive nitrogen limitation hypothesis,” which assumes that increased growth rates of trees would deplete poor soils of nitrogen, thus mediating the positive effects of increased CO2. This is a scenario based on an unproven hypothesis, not reality, which stubbornly refuses to support the hypothesis. Many studies show that, contrary to the hypothesis, although roots grow deeper and produce more fine hairs, soil and forest floor are enriched in nitrogen from biological sources, ie, increased root mass and leaf litter supporting beneficial microbes in the soil. Deeper roots with more fine hairs also make plants mean enhanced tolerance to dryer conditions. (also see next item)
c.) One benefit of increased CO2 is that the stomata (openings) of leaves, which take in CO2 and emit water vapor and oxygen, are reduced, leading to less water loss, enhanced water use and improved tolerance to dryer conditions. At elevated CO2 levels, stomata do not need to be open as far to allow sufficient CO2 in for photosynthesis and, as a result, less water is lost through transpiration. In controlled studies, an additional benefit of reduced stomata openings is a reduction in ozone damage.
d.) The increased rate of growth of plants, from forests to sea algae, results in more of certain cooling aerosols being produced. These include Carbonyl Sulfide (COS) from soil and seas that become highly reflective sulfate in the stratosphere to reflect more solar radiation back into space; iodo-compounds from sea algae that nucleate clouds to reflect more solar radiation back into space; and dimethyl sulfide (DMS), from seas that nucleates clouds as well as other aerosols such as isoprene from trees with similar effects.
The increase in carbon dioxide is greening many arid regions because of more efficient use of water and the increased growth rate. Sub-Saharan Africa is blooming, the Amazonian jungle is flourishing and global vegetative cover is increasing. The effect on ocean phytoplankton is equally as dramatic. Significant reduction of carbon dioxide levels as proposed by the various climate agreements would have a detrimental effect on plant growth and consequently food supplies. A concentration of 150 ppm is too low for photosynthesis to occur and plants die.
Hormesis is a phenomenon, commonly seen in medicine and nutrition, where a low or moderate concentration or dose results in a positive effect, but a larger dose results in damage. For instance, some salt and water are necessary to good health, but beyond a certain point, ingesting more can be harmful or fatal. The effect of CO2 on plant life appears to be one such system. Increased CO2 obviously benefits plant life, but it is uncertain at what level CO2 might have a detrimental effect on growth. In professional greenhouses and experiments, even ten times the current level is still beneficial.
 Example: Phillips, R.P., Finzi, A.C. and Bernhardt, E.S. 2011. “Enhanced root exudation induces microbial feedbacks to N cycling in a pine forest under long-term CO2 fumigation”. Ecology Letters14: 187-194.
 See review article of research papers: “Responses of agricultural crops to free-air CO2 enrichment” Kimball, B.A., Kobayashi, K. and Bindi, M., Advances in Agronomy77: 293-368 2002.
 Iodo-compounds contain iodine derived from seaweed