Feeding the world’s population in the coming years is going to be a challenge. The United Nations estimates that by 2100, there will be an average of 11 billion people on Earth; that’s 4 billion more than there are today.
Several solutions have been suggested, such as farming and eating insects. One of the most promising, however, involves the Green Revolution, which refers to the renovation of agricultural practices that began in Mexico in the 1940s. Because of their success in producing more agricultural products in that country, Green Revolution technologies—such as improved irrigation, increased use of manufactured fertilizer and higher-yield crop strains—spread throughout the world in the 1950s and 1960s, significantly increasing the amount of calories produced per agricultural acre.
The Green Revolution looked like an auspicious answer; that is, until recently.
Increasing food productivity—and CO2
The high-yield crops developed during the Green Revolution were domesticated plants bred specifically to respond to fertilizers and produce an increased amount of grain per acre planted. But a brand-new report published online in the November 19, 2014, issue of the international science journal Nature states that the Green Revolution’s intense farming techniques are powerful enough to alter the Earth’s atmosphere—and not for the better. Those practices have boosted the seasonal rise in atmospheric carbon dioxide about 15 percent during the last five decades (or about 0.3 percent every year).
In the Northern Hemisphere during late summer and early fall, carbon dioxide (Earth’s main greenhouse gas) in the atmosphere hits an annual low. That’s when the hemisphere’s plants—at their maximum growth—take in carbon dioxide and release oxygen. Since the Northern Hemisphere has a greater continental landmass than the Southern Hemisphere, it has more plant life. In contrast, in mid to late fall, when plants are decomposing and releasing stored carbon, the atmosphere’s CO2 levels rapidly increase.
During the last 50 years, the size of this seasonal swing has grown. Results of this new study, funded by the National Science Foundation’s MacroSystems Biology Program, has shown that agricultural production may generate up to a quarter of the rise, with corn playing a leading role.
Using global statistics for four leading crops—corn, rice, soybeans and wheat, which together represent about 64 percent of all calories consumed worldwide—scientists found that their production in the Northern Hemisphere has more than doubled since 1961, which translates to about a billion metric tons of carbon captured and released each year.
While the Green Revolution’s increased food productivity speaks well for agriculture, it may be adding to the problem of rapid climate change. While corn, rice, soybeans and wheat occupy about 6 percent of the vegetative land area in the Northern Hemisphere, they are responsible for up to a quarter of the total increase in the seasonal exchange of atmospheric CO2.
It isn’t easy—or always best—being green
It appears that the Green Revolution has a positive and a negative side. Certainly, countries all over the world benefited from it. In the early 1960s, for example, India was on the brink of mass famine because of its rapidly growing population. Green Revolution techniques resulted in the development of a new variety of rice, IR8, which produces more grain per plant when grown with irrigation and fertilizers. Today, IR8 rice usage has spread throughout Asia, and India is one of the world’s leading rice producers. Yet, since the Green Revolution causes increases in plants’ seasonal growth and decay, it has also escalated the amount of carbon dioxide they release into the atmosphere.
Of course, the Green Revolution alone cannot fully account for the trend and spatial patterns toward increasing seasonal change in CO2. But this new study does demonstrate how modifications in the way we manage the land can alter the “breathing” of the biosphere.
It’s another chapter in the story of how big a footprint our human activity has on the planet, even as we try to solve the challenges of the future.
Are there other cases where going green isn’t always good?
Here’s to finding your true places and natural habitats,