A new study suggests that modern farming made more productive by technology is having a huge impact on carbon dioxide cycles in the atmosphere — raising questions about whether policymakers will target farms as it seeks to get a hold on the global problem.

Two teams of researchers recently uncovered new details about the seasonal breathing cycle of terrestrial plants, which take in and then emit carbon dioxide every year, a “breathing” pattern which has only gotten deeper in the last half century, according to the Christian Science Monitor.

A NASA video released this past week vividly depicted carbon dioxide emissions first being belched out from the United States, Europe, and East Asia and then being spread across the Northern Hemisphere, before plants took hold in the summer and scrubbed the atmosphere clean, only to allow those plumes of CO2 to return once they entered their dormant phase in the winter.

Researchers now believe that farming is responsible for 20 to 50 percent of long-term increases in CO2 absorbed during the growing season and given off during dormant months.

The research appeared in the journal Nature.

This influence doesn’t come from an increase in the amount of land that is being planted, but rather the exponential increases in farm productivity, including improved fertilizer, more efficient crop breeds, and better irrigation, which has been about twice as influential on atmospheric CO2 levels as the fertilizing effect, according to scientists.

The unsettling results could give policymakers some difficult choices ahead as it seeks to get a handle on CO2 emissions worldwide.

Most scientists haven’t appreciated the impact humans have on the carbon cycle based on the models they produce, according to the researchers. They are still trying to determine the broader implications of their results.

A research team at the Scripps Institution of Oceanography in La Jolla, Calif., reported last year that there were larger fluctuations in the CO2 exchanges between the atmosphere and terrestrial plants. Originally, they fingered larger forests and young, fast-growing species in forests destroyed by logging or fire, as well as the migration of plants north as the climate has warmed. But the ecosystem models produced a 30 to 60 percent increase in “deep breathing” over what was expected, suggesting to researchers that these models could be seriously under-reporting future changes.

However, researchers now believe that these improved farming methods could contribute to those increases in “deep breathing” fluctuations.