It seems counter-intuitive, but rising crop yields actually add more carbon dioxide to the atmosphere. Over the past few decades, food production has increased sharply to meet demands for rising population. According to a new study conducted by scientists at Boston University, increasing crop yields account for as much as 25% of the seasonal increase in greenhouse gases.
Crops are like a sponge
Plants absorb CO2 in spring and summer convert solar energy into food, leading to a drastic drop in atmospheric CO2. But that absorbed carbon dioxide is released back to the atmosphere in fall and winter, said Chris Kucharik, co-author of the study and a professor at the University of Wisconsin-Madison. Findings of the study were published in the journal Nature.
It’s not that crop production is adding more greenhouse gases to the atmosphere. Instead, crops are like a sponge for CO2. Scientists say the sponge has become a lot bigger, holding and releasing more of carbon. Worldwide food production is expected to double in the next five decades. Findings of the latest study could help researchers improve climate models and better understand carbon dioxide buffering capacity of ecosystems.
The connection between crop yields and CO2 increase
It’s yet another piece of evidence that when humans do something at a large scale, we “greatly influence” the atmospheric composition. Though farmland has increased very little, crop production has increased significantly in the last 50 years, thanks to plant breeding, fertilization innovations, and irrigation. Cropland accounts of just 6% of the total green area in the Northern Hemisphere. But it is a “dominant contributor” to the 50% increase in the carbon dioxide seasonality cycle.
Among various crops, corn plays the biggest role in disturbing global temperatures, followed by wheat, rice and soybeans. Scientists said these crops absorb and release a billion metric tons of CO2 annually. Until now, the scientific community had missed the connection between rising crop yields and the seasonal CO2 increase.