How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic

A Half-Century Forward Look at Agricultural Production in Canada's Atlantic Provinces
Bootsma, A., Gameda, S. and McKenney, D.W.  2005.  Potential impacts of climate change on corn, soybeans and barley yields in Atlantic Canada.  Canadian Journal of Plant Science 85: 345-357.

What was done
The authors derived relationships between agroclimatic indices and average yields of grain corn (Zea mays L.), soybeans (Glycine max L. Merr.) and barley (Hordeum vulgare L.) obtained from field trials conducted in eastern Canada and used them to estimate potential impacts of projected climate change scenarios on anticipated average yields of these commodities for the 2040 to 2069 period.

What was learned
Based on a range of available heat units projected by multiple General Circulation Model (GCM) experiments, Bootsma et al. determined that average yields achievable in field trials could increase by 40 to 115% for corn and 21 to 50% for soybeans by 2040 to 2069, "not including the direct effect of increased atmospheric CO2 concentrations."  Adding expected CO2 increases into the mix, along with gains in yield anticipated to be achieved through breeding and improved technology, these numbers rose to 114 to 186% for corn and 117 to 157% for soybeans.

Initial yields of barley, on the other hand, were predicted to decline, and by as much as 25% in areas with significant water deficits; but after reviewing the scientific literature on the subject, the Canadian researchers concluded that the direct effect of increased CO2 alone "would more than offset the yield reductions anticipated due to effects of rising temperature and changes in water deficit."  All things considered, therefore, they estimate that "barley yields would increase by an average of about 15% under this scenario."

What it means
In light of their fantastic findings, Bootsma et al. predict there will be a "switch to high-energy and high-protein-content crops (corn and soybeans) that are better adapted to the warmer climate."  However, they say "there will likely still be a considerable area of land seeded to barley and other small grain cereals, as these are very desirable in rotation with potatoes."  Consequently, if the GCM-based climate-change predictions prove correct, Canada will be immensely blessed by the incredible boost the changed conditions will bring to the country's agricultural productivity.

Reviewed 23 November 2005