John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
The large swath of corn running through the United States "boasts more photosynthetic activity than any other spot on Earth," says NASA.
Science has long known that corn, out of all types of vegetation, is particularly adept at removing carbon emissions from the air. Now, using sophisticated satellite data, NASA reports it's got a new bead on just how much the silky plant is affecting the carbon cycle.* For one thing, the fecundity of corn in the United States is a lot more than expected: Past research underestimated the plant's nationwide growth by as much as 60 percent, says the space agency.
To investigate the vast abundance of maturing kernels in America, NASA trained satellites down at the U.S. "Corn Belt," which stretches from Ohio to Nebraska and Kansas. Because chlorophyll emits a tiny bit of invisible fluorescence, the space-locked instruments detected what the human eye cannot: An intensely productive swath of greenery that, during the growing season, shows a photosynthetic frenzy greater than any other place on Earth. At its peak in July, the Corn Belt can even hold reservoirs of chlorophyll that are 40 percent greater than what's found in the Amazon.
Here's the model that resulted from NASA's satellite efforts: It shows fluorescence emitted by land plants from 2007 to 2011, with an area of intense chemical activity centered right on the Corn Belt:
How might this innovative way of poking at plants help further climate science? The researchers involved in the effort suggest it will provide a more accurate way to measure the extent of vegetation growth, which can be affected each year by things like irrigation. Better info would in turn help fine-tune the reigning climate models, always an important thing for predicting the world we'll soon be living in, according to the space agency:
Unlike most vegetation, food crops are managed to maximize productivity. They usually have access to abundant nutrients and are irrigated. The Corn Belt, for example, receives water from the Mississippi River. Accounting for irrigation is currently a challenge for models, which is one reason why they underestimate agricultural productivity.
"If we don't take into account irrigation and other human influences in the agricultural areas, we're not going to correctly estimate the amount of carbon taken up by vegetation, particularly corn," [NASA's Joanna] Joiner said. "Corn plants are very productive in terms of assimilating carbon dioxide from the atmosphere. This needs to be accounted for going forward in trying to predict how much of the atmospheric carbon dioxide will be taken up by crops in a changing climate."
* Correction: The original headline and lede for this story implied that corn was "slowing" climate change. While the plant does remove carbon from the atmosphere, it is not a great form of carbon sequestration in the long-term.