Atmospheric Hydrogen Up 70% Over 150 Years
Earth system scientists have found that molecular hydrogen (H2) in the atmosphere increased by 70%. A coalition between UC Irvine, NOAA, the University of Colorado Boulder, and UC San Diego, studied air confined in layers of Antarctic ice and snow and found that molecular hydrogen increased from 330 to 550 parts per billion in Earth's atmosphere from the years 1852 through 2003.
Why this Matters
H2 emerges as a result of fossil fuel combustion, biomass burning, and the oxidation of methane -- to name a few sources. Like CO2, H2 in excess affects the ozone layer and global warming and is evidence of the human causes of climate change.
Aging air is trapped in the perennial snowpack above an ice sheet, and sampling it gives us a highly accurate account of atmospheric composition over time. Our paleoatmospheric reconstruction of H2 levels has greatly enhanced our understanding of anthropogenic emissions since the beginning of the industrial revolution.
Stepping on the Gas
This growth of H2 in the atmosphere is the result of human activities, particularly the burning of fossil fuels. That said, there are sources of H2 we haven't located. Patterson continued:
Government policies on tailpipe emissions have led to a decrease in carbon monoxide in the atmosphere, so we should have expected to see the same impact on molecular hydrogen, but that appears to not be the case. There's no evidence that atmospheric molecular hydrogen emissions decreased in the 20th century, so we are likely underestimating nonautomotive sources of the gas.
The researchers suggested that one of these sources may be zero-carbon hydrogen power. Though hydrogen has been touted as a low-emissions alternative to fossil fuels, there is an emerging consensus that natural gas could be damaging to the climate.
Most hydrogen used today is extracted from natural gas in a process that requires a lot of energy and emits vast amounts of carbon dioxide and methane, along with leaking hydrogen into the atmosphere.
Scottish Power: What is Green Hydrogen?, Mar 8, 2021.
University of Newcastle, Australia: New green hydrogen made from solar power and air, Spetember 3, 2020.