Can people know what the environment witnessed 150 years ago? On the theoretical level, it might seem hard, or even impossible, but researchers at the University of California (UCI) have made it possible using ice in Antarctica.
In a study published in the journal Proceedings of The National Academy of Science, the researchers announced that the molecular hydrogen increased from 330 to 550 parts per billion in Earth's atmosphere from 1852 to 2003, after they studied air trapped in compacted layers of Antarctic ice.
Hydrogen (H2) is a byproduct of fossil fuel combustion, biomass burning and the oxidation of methane, among other sources, and has an impact on global warming and the ozone layer. Thus, monitoring its levels is a key factor that helps examine the impact of human activities on the environment.
"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," said John Patterson, UCI researcher in a report posted on the university's website on September 10.
Patterson said the bulk of the growth in H2 is attributable to human activities, especially those resulting in transportation-sourced emissions.
"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," he said.
"There may be a new source of H2 emissions looming on the horizon as more people adopt zero-carbon hydrogen power for autos and other needs, leading to the possibility of leakage into the atmosphere," he explained.