GLOBAL INCREASE OF ATMOSPHERIC MOLECULAR-HYDROGEN

IT is now well known that levels of atmospheric CO2, CH4, N2O and CO are increasing at substantial rates as a result of human activities. Here we report that levels of another trace gas, molecular hydrogen, are also increasing. Our systematic measurements between 1985 and 1989 show that the concentration of H2 increased at an average rate of 3.2 ± 0.5 parts per 109 by volume per year (a relative increase of 0.6 ± 0.1% yr-1). These increases originate from anthropogenic sources. Higher levels of hydrogen will add more water vapour to the stratosphere, where it can affect stratospheric ozone. © 1990 Nature Publishing Group.