The relationships between crop growth, climate change and atmospheric CO2 may be more complicated than previously thought according to the latest research.
An American research team says cropping cycles contribute to seasonal rises in CO2 levels. In the Northern Hemisphere the level of atmospheric carbon dioxide drops in the summer when plants are actively growing, then climbs again after the growing season or when they decompose. The size of this seasonal swing has increased by 50 per cent over the last 50 years.
With global food productivity expected to double over the next 50 years, the researchers say the findings should be used to improve climate models and better understand the atmospheric CO2 buffering capacity of ecosystems, particularly as climate change may continue to perturb the greenhouse gas budget.
“This is another piece of evidence suggesting that when we (humans) do things at a large scale, we have the ability to greatly influence the composition of the atmosphere,” says Chris Kucharik, a co-author of the study.
To make things more complicated, another team of researchers from Princeton University says that the carbon in soil – which contains twice the amount of carbon in all plants and Earth’s atmosphere combined – could become increasingly volatile as people add more carbon dioxide to the atmosphere, largely because of increased plant growth.
More research is required to understand these complex relationships and the potential effects on crop growth around the world.