The crops that are grown globally, and sustain close to 4.5 billion people worldwide, are wheat, maize, rice, and soybeans. With these crops sustaining more than half of the world’s population, how are they not apart of the bigger conversation surrounding the rising levels of carbon dioxide?
In an article by Samson Reiny, published on NASA’s website, he discusses the fact that rising levels of carbon dioxide could both, simultaneously, help and harm the four crops listed above. He makes the argument that, so far, climate prediction models have only taken into account the effect that carbon dioxide will have on yields and not the effect they have on water efficiency, and even then are only measuring temperate climates. He reports on a simulation conducted by a Delphine Deryng in which the yields and evapotranspiration were manipulated to “to estimate crop water productivity” by using a measurement of yield that was produced per unit of water. In total, there were 30 simulations, six of which were using data from “five different global climate models” which assumed the carbon dioxide levels that were reported in 2000 had doubled by 2080. Another simulation models used assumed that the carbon dioxide levels had remained stagnant since 2000.
The simulation crops that operated at the 2000 carbon dioxide levels the yields suffered dramatically. However, with the doubled carbon dioxide levels predicted at 2080 both yields and water efficiency had a dramatic increase. These increases, however, depend upon regions and whether the crops were irrigated or rain fed. For example, Reiny discusses maize in terms of losses with the doubled carbon dioxide, due to the crop’s already efficiency of photosynthesis, maize would yield 15% less in areas using irrigation and 8% in rain fed areas. However, these losses would close to double without the doubling of carbon dioxide in the simulation, and the assumed doubling of carbon dioxide since 2000 would reveal that wheat would show crop yield increases “across the board”. These yields would be 8% increased with a 50% increase in water efficiency in rain fed areas.
Essentially, there needs to be far more research done about carbon dioxide and its effects, but the four most globally powerful crops need to be apart of that conversation. Through these simulations there has been discovered that a lot more research has yet to be done on the effect of carbon dioxide on these crops, but more so in developing countries that tend to have drier and more arid climates instead of the temperate climates of the west. Our climate models, and models for how we plan to feed future generations, need to include the countries that are not apart of the western hemisphere. How would any climate or environmental model be accurate if we exclude them?
