MSGID: 1:317/3 6279ea85   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Confirmed: Atmospheric helium levels are rising    
    A by-product released by use of fossil fuels has been increasing since   
   1974    
      
     Date:   
         May 9, 2022   
     Source:   
         University of California - San Diego   
     Summary:   
         Scientists used an unprecedented technique to detect that levels   
         of helium are rising in the atmosphere, resolving an issue that   
         has lingered among atmospheric chemists for decades.   
      
      
      
   FULL STORY   
   ==========================================================================   
   Scientists at Scripps Institution of Oceanography at UC San Diego used   
   an unprecedented technique to detect that levels of helium are rising in   
   the atmosphere, resolving an issue that has lingered among atmospheric   
   chemists for decades.   
      
      
   ==========================================================================   
   The atmospheric abundance of the 4-helium (4He) isotope is rising because   
   4He is released during the burning and extraction of fossil fuels. The   
   researchers report that it is increasing at a very small but, for the   
   first time, clearly measurable rate. The 4He isotope itself does not add   
   to the greenhouse effect that is making the planet warmer, but measures   
   of it could serve as indirect markers of fossil-fuel use.   
      
   The National Science Foundation-supported study appears today in the   
   journal Nature Geoscience.   
      
   "The main motivation was to resolve a longstanding controversy in the   
   science community about atmospheric helium concentrations," said study   
   lead author Benni Birner, a former graduate student and now postdoctoral   
   researcher at Scripps Institution of Oceanography at UC San Diego.   
      
   The isotope 4He is produced by radioactive decay in the Earth's crust and   
   accumulates in the same reservoirs as fossil fuels, in particular those   
   of natural gas. During the extraction and combustion of fossil fuels,   
   4He is coincidentally released, which creates another means to evaluate   
   the scale of industrial activity.   
      
   The study's breakthrough is in the technique the Scripps Oceanography   
   team used to measure how much helium is in the atmosphere. Birner and   
   Scripps geoscientists Jeff Severinghaus, Bill Paplawsky, and Ralph   
   Keeling created a precise method to compare the 4He isotope to levels   
   of the common atmospheric gas nitrogen. Because nitrogen levels in the   
   atmosphere are constant, an increase in He/N2 is indicative of the rate   
   of 4He buildup in the atmosphere.   
      
   Study co-author and Scripps Oceanography geochemist Ralph Keeling,   
   overseer of the famed carbon dioxide measurement known as the   
   Keeling Curve, describes the study as a "masterpiece of fundamental   
   geochemistry." Though helium is relatively easy for scientists to detect   
   in air samples, present at levels of five parts per million of air,   
   no one had done the work to measure it carefully enough to observe an   
   atmospheric increase, he said.   
      
   The study also provides a foundation for scientists to better understand   
   the valuable 3-helium (3He) isotope, which has uses for nuclear fusion,   
   cryogenics, and other applications. Proposals to acquire the scarce gas   
   from the moon are an indication of the lengths to which manufacturers   
   will go to harvest it.   
      
   According to previous work by other researchers, the 4He isotope exists   
   in the atmosphere in what appears to be an unvarying ratio with 3He. The   
   atmospheric rise of 4He isotope measured at Scripps therefore implies   
   that the 3He isotope must be rising at a comparable rate as 4He. The   
   research by Birner's team raises several questions about the accuracy   
   of scientists' previous assumptions about how 3He is produced and in   
   what quantity.   
      
   "We don't know for sure, but I wonder if there is more 3He coming out of   
   the Earth than we previously thought, which could perhaps be harvested   
   and fuel our nuclear fusion reactors in the future," Birner said.   
      
   "The study lays in starker relief a controversy surrounding the rare   
   helium isotope 3He," said Keeling. "The implications are far from clear,   
   but it begs additional work."   
      
   ==========================================================================   
   Story Source: Materials provided by   
   University_of_California_-_San_Diego. Original written by Robert   
   Monroe. Note: Content may be edited for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Birner, B., Severinghaus, J., Paplawsky, B. et al. Increasing   
      atmospheric   
         helium due to fossil fuel exploitation. Nat. Geosci., 2022 DOI:   
         10.1038/ s41561-022-00932-3   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2022/05/220509112102.htm   
      
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