Fossil Fuels Drive Increase in Atmospheric Helium
By Jennifer Schmidt, Eos/AGU.
Excerpt: The release of carbon dioxide (CO2) during the extraction and burning of fossil fuels has contributed to major changes in Earth’s atmosphere in the centuries since humans realized their value as an energy source. Often accompanying CO2 are benign gases such as helium (He) that can be used to trace such emissions. Scientists have long speculated that the amount of 4He—an isotope of helium—in the atmosphere is increasing because it is found in the same reservoirs as natural gas and other hydrocarbons. But measurements have so far been conflicting and imprecise. Now, researchers have developed a new way to measure the noble gas, shedding light on the decades-old conundrum. “With our measurements, for the first time, we’re able to demonstrate that [the theory is] actually true, that helium concentrations in the atmosphere are increasing,” said Benjamin Birner, an atmospheric chemist and postdoctoral researcher at Scripps Institution of Oceanography. The new discovery could lead scientists to better identify sources of CO2 in the atmosphere, which could guide policies to curb emissions. The increase in 4He also raises questions about its isotopic companion, 3He, and a potential undiscovered reservoir of the gas—a critical resource in some research and commercial industries.…