Impacts of Changes in Atmospheric O2 on Human Physiology. Is There a Basis for Concern?

Research output: Contribution to journalReviewResearchpeer-review


  • Ralph F. Keeling
  • Frank L. Powell
  • Shaffer, Gary
  • Peter A. Robbins
  • Tatum S. Simonson

Concern is often voiced over the ongoing loss of atmospheric O-2. This loss, which is caused by fossil-fuel burning but also influenced by other processes, is likely to continue at least for the next few centuries. We argue that this loss is quite well understood, and the eventual decrease is bounded by the fossil-fuel resource base. Because the atmospheric O-2 reservoir is so large, the predicted relative drop in O-2 is very small even for extreme scenarios of future fossil-fuel usage which produce increases in atmospheric CO2 sufficient to cause catastrophic climate changes. At sea level, the ultimate drop in oxygen partial pressure will be less than 2.5 mm Hg out of a baseline of 159 mmHg. The drop by year 2300 is likely to be between 0.5 and 1.3 mmHg. The implications for normal human health is negligible because respiratory O-2 consumption in healthy individuals is only weakly dependent on ambient partial pressure, especially at sea level. The impacts on top athlete performance, on disease, on reproduction, and on cognition, will also be very small. For people living at higher elevations, the implications of this loss will be even smaller, because of a counteracting increase in barometric pressure at higher elevations due to global warming.

Original languageEnglish
Article number571137
JournalFrontiers in Physiology
Number of pages16
Publication statusPublished - 2 Mar 2021

    Research areas

  • atmospheric oxygen, fossil fuels, global change, evolution, V, O 2max, human health, hypoxia, high altitude

Number of downloads are based on statistics from Google Scholar and

No data available

ID: 258764421