More potent than carbon dioxide, nitrous oxide levels in California may be nearly three times higher than previously thought

Lawrence Berkeley National Laboratory News Center: Using a new method for estimating greenhouse gases that combines atmospheric measurements with model predictions, Lawrence Berkeley National Laboratory (Berkeley Lab) researchers have found that the level of nitrous oxide, a potent greenhouse gas, in California may be 2.5 to 3 times greater than the current inventory.

At that level, total N2O emissions—which are believed to come primarily from nitrogen fertilizers used in agricultural production—would account for about 8 percent of California’s total greenhouse gas emissions. The findings were recently published in a paper titled “Seasonal variations in N2O emissions from central California” in Geophysical Research Letters. Earlier this year, using the same methodology, the researchers found that levels of methane, another potent greenhouse gas, in California may be up to 1.8 times greater than previous estimates.

“If our results are accurate, then it suggests that N2O makes up not 3 percent of California’s total effective greenhouse gases but closer to 10 percent,” said Marc Fischer, lead researcher on both studies. “And taken together with our previous estimates of methane emissions, that suggests those two gases may make up 20 to 25 percent of California’s total emissions. That’s starting to become roughly comparable to emissions from fossil fuel CO2.”

Accurate estimates of the California’s greenhouse gas emissions are important as the state works to reduce emissions to 1990 levels by 2020, as mandated by a law known as AB 32. The vast majority of the reduction efforts have been focused on CO2….

This map shows the amount of nitrous oxide emissions in California (in nanomoles per square meter per second). The "x" represents the location of the measurement tower in Walnut Grove, CA. From the LBNL website