Scientists have found that helium-3, is ten times more common on Earth than previously known. It is important for clean energy, but it is mainly found on the moon.
Benjamin Birner, a postdoctoral scholar in geosciences at the University of California San Diego, with his team, has captured evidence for a previously unknown abundance of helium-3 in the atmosphere, which “presents a major puzzle in the helium-3 budget” and “motivates a search for missing helium-3 sources on Earth, especially since helium-3 is considered an important, yet scarce, resource,” according to a study published on Monday in Nature Geoscience.
Helium-3 could be the ideal fuel for nuclear fusion when nuclear fusion is a practical option.
“Our approach not only avoids measuring the rare isotope”—meaning 3He—“which improves our measurement precision, but also normalizes the abundance of 4He to N2,” said Birner, who also led a study last year in Atmospheric Measurement Techniques that delves deeper into the many conceptual advances and technical innovations of this new method.
The team applied the new technique to 46 air samples acquired between 1974 and 2020 which gave a new estimate of atmospheric helium-4 changes across a timescale of decades. It was found that helium- levels had shown an increase which automatically means an abundance of helium-3.
“The inferred 3He change is more than 10x the natural geological fluxes,” Birner added. “We know that 3He is produced also by the decay of tritium. Tritium was released by humans in nuclear bomb tests, by the current stockpile of nuclear warheads and is probably also made in some nuclear power plants. However, our estimate of these sources suggests they can only account for about 10% of the inferred 3He increase. It is not clear at all where the rest comes from.”
“Now if you measure CO2 alone, the inversion will tell you the flux of CO2 but by also using helium, we may also be able to say what fraction of that CO2 came from natural gas burning because helium should be associated with natural gas but not as much with other emission sources such as car traffic,” he concluded. “I am now working on further developing the method to detect local changes of helium in San Diego. With some more tweaks, I am confident that precision will be good enough to see daily local variability in helium concentrations.”
