How does rising atmospheric CO2 affect marine organisms?

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Global Warming and Chinese Food Security
Reference
Xiong, W., Lin, E., Ju, H. and Xu, Y. 2007. Climate change and critical thresholds in China's food security. Climatic Change 81: 205-221.

What was done
The authors used "the A2 (medium-high GHG emission pathway) and B2 (medium-low) climate change scenarios produced by the Regional Climate Model PRECIS, the crop model CERES, and socio-economic scenarios described by IPCC SRES, to simulate the average yield changes per hectare of three main grain crops (rice, wheat, and maize) at 50 km x 50 km scale" for the entire country of China.

What was learned
The four researchers from the Institute of Environment and Sustainable Development in Agriculture of the Chinese Academy of Agricultural Sciences in Beijing report finding that "the yield per hectare for the three crops would fall consistently as temperature rises beyond 2.5°C." However, they also found that "when the CO2 fertilization effect was included in the simulation, there were no adverse impacts [our italics] on China's food production under the projected range of temperature rise (0.9-3.9°C)."

What it means
If air temperatures continue to rise throughout the next few decades - for whatever reason - it would appear to be imperative that the air's CO2 concentration continue to rise right along with them; for only under such conditions will China, as well as most of the rest of the nations of the world, be able to adequately feed the larger numbers of people that will reside within their boundaries just a few decades hence, without usurping unconscionable amounts of land and freshwater resources from what could be called wild nature, which actions would inevitably lead to the extinctions of innumerable species of both plants and animals.

For more information on this important but largely-ignored problem, see the section entitled The CO2-Induced Preservation of Terrestrial Species in our critique of James Hansen's 26 April 2007 testimony to the Select Committee of Energy Independence and Global Warming of the U.S. House of Representatives.

Reviewed 5 September 2007