Carbon dioxide levels breach a new ceiling

  • Carbon dioxide levels in the atmosphere scaled another psychologically important — and immensely worrying — peak, going past 410 parts per million (ppm).
  • Atmospheric carbon dioxide concentrations are now at the highest levels they have been in at least 3 million years.
  • More importantly, over the past couple of years, they have increased faster than probably ever before.
  • While the rate of growth of CO2 in the atmosphere has shown regular ups and downs, the levels grew less than 1 ppm every year between 1959 — when one of the most important sites for taking these measurements, the Mauna Loa Observatory in Hawaii, started keeping records — and 1964.

why is an increased concentration of CO2 bad for the Earth?

  • Simply put, CO2 is one of several gases that trap heat in the atmosphere, creating the “greenhouse effect” that keeps the Earth from getting too cold for life. But if the CO2 increases, extra heat is trapped in the atmosphere, and global average temperatures begin to rise. The more the CO2, the greater the atmosphere’s capacity to trap heat.
  • “Atmospheric CO2 is now higher than it has been for several million years, as measured in ice cores and ocean sediments,”
  • Also increasing CO2 concentration is vegetation. There is a roughly 7 ppm swing between the peak and trough values in a year, mainly because in winter in the northern hemisphere, the dormant vegetation doesn’t remove CO2 from the air.
  • Similarly, a drought caused by a strong El Niño event could trigger a spike in CO2 levels. A minor comfort is that concentration levels could fall below the 410 ppm mark as daily measurements fluctuate — but if there is no drastic action, there could be no reversal. The concentration is not expected to fall below 400 ppm any time soon in any case.
  • The Paris Agreement, considered an achievement of global action in which all nations came together and vowed to keep global temperature rise to below 2 degrees Celsius above pre-industrial levels, also resolved to pursue efforts to limit temperature increase further to 1.5 degrees Celsius.
  • Some scientists say that to do that, the upper limit for CO2 concentrations would have to be 450 ppm.


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