Nitrous Oxide: No Laughing Matter

Abstract

Despite its long-recognized importance, nitrous oxide (N₂O, also commonly referred to as laughing gas) sometimes seems like the forgotten atmospheric gas. Concerns about the stratospheric ozone layer have largely focused on reactions of ozone with chlorine and bromine atoms released from the atmospheric dissociation of chlorofluorocarbons and other anthropogenic halocarbons. Meanwhile, concerns about human-induced effects on Earth's climate have concentrated on carbon dioxide (CO₂) and methane (CH₄) emissions from fossil fuels and other sources. However, future changes in climate and in the distribution of stratospheric ozone depend on the emissions and changing atmospheric concentration of N₂O. The report by Ravishankara et al. on page 123 of this issue (1) not only adds to the scientific understanding of this important gas, but is also a strong reminder that nitrous oxide deserves much more attention and consideration for policy action to control future human-related emissions.