How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic

Water Use Efficiencies of Northern European Trees: How Have They Responded to the Historical Rise in the Air's CO2 Content
Waterhouse, J.S., Switsur, V.R., Barker, A.C., Carter, A.H.C., Hemming, D.L., Loader, N.J. and Robertson, I. 2004. Northern European trees show a progressively diminishing response to increasing atmospheric carbon dioxide concentrations. Quaternary Science Reviews 23: 803-810.

What was done
The authors determined the intrinsic water use efficiency (IWUE) responses of three tree species growing across northern Europe -- pedunculate oak (Quercus robur L., growing on two sites in Northwest Norfolk, England, as well as a single site in South Bedfordshire, England, and two sites in Southwest Finland), common beech (Fagus sylvatica L., growing on one site in South Bedfordshire, England) and Scots pine (Pinus sylvestris L., also growing on one site in South Bedfordshire, England) -- to the increase in atmospheric CO2 concentration experienced between 1895 and 1994, using parameters derived from measurements of stable carbon isotope ratios of trunk cellulose.

What was learned
Waterhouse et al. report that "all species at all the sites show a long-term increase in their values of IWUE during the past century," noting that "the main cause of this common behaviour is likely to be the increase in atmospheric CO2 concentration." Linearly extrapolating these responses (which occurred over a period of time when the air's CO2 concentration rose by approximately 65 ppm) to what would be expected for the more common 300-ppm increase employed in the majority of atmospheric CO2 enrichment experiments, the IWUE increases they derived amount to +158 14% for the oak trees (mean standard error for the five sites), +195% for the pine trees, and +220% for the beech trees, as best we can determine from the graphs of their results.

What it means
These responses are huge, and are probably not due to rising CO2 alone but to the positive synergism that occurs when atmospheric CO2 and temperature rise together [see Interactive Effects of CO2 and Temperature on Plant Growth (Trees) in our Subject Index], as these parameters have done over the past century or so, which once again demonstrates that the "twin evils" of the climate-alarmist crowd (high temperatures and CO2 concentrations) are just what the biosphere loves.

Reviewed 5 May 2004