CO2 Levels

CO2 levels are rocketing up.

  • The orange line shows how the level of “carbon dioxide in our air” has moved over the last 400,000 years.
  • Before 1950, CO2 levels moved between :
    • lows near 180 parts per million (ppm) during ice ages, and
    • highs near 300 ppm.
  • The CO2 level in 1960 was about 317 ppm.
  • The CO2 level in 2019 is now about 409 ppm. This is 36% above the previous high of 300 ppm.
  • The CO2 level is going up like a rocket.
  • See the latest NASA Carbon dioxide graph.

The CO2 levels are rising faster

In the 1960s, the increase of CO2 concentration was about one ppm per year. Now the increase is about two ppm per year and getting bigger. It may soon be three ppm per year.
Atmospheric CO2 accumulating faster than ever (New Scientist, 2006)

If CO2 keeps increasing by 2.0 ppm each year, the CO2 level will reach 571 ppm by 2100.

Carbon dioxide levels are alarming.

Over the last hundred years, humans have burnt vast amounts of coal, oil, gas, and wood. This burning has released enormous amounts of carbon dioxide (CO2) into our atmosphere.

Now we know that carbon dioxide is a greenhouse gas and acts like a blanket over the planet.  It limits the amount of radiant heat that escapes into outer space and tends to warm the Earth. We also know that global temperature and carbon dioxide levels have moved together for 400,000 years. So the current high carbon dioxide levels carry the threat of a substantial increase in temperature and sea levels.

Carbon dioxide levels above 400 ppm occurred during the Pliocene, which extended from 5.3 to 2.6 million years ago. During this period, the sea level was about 25 metres higher than at present.

Our species has never experienced such high levels of CO2

The concentration of CO2 in our atmosphere is already far above any level experienced for 800,000 years. Our species, Homo Sapiens, emerged about 250,000 years ago. The species from which we evolved, Homo Erectus and Homo Neanderthalensis, emerged about 400,000 years ago.

Our species, and the web of life that supports us, evolved with CO2 levels between 180 and 300 ppm.  They have never before experienced CO2 concentrations at the current 409 ppm, let alone the forecast levels. If we allow these high levels of CO2 to remain for an extended period, warming the planet more and more, we do not know whether the environment that has nurtured our species can survive.

These high levels of CO2 risk life as we know it

Carbon dioxide levels influence global temperatures.  While CO2 levels remain above about 300 ppm, the oven remains turned on –  and we are cooking our planet. (See my page on how fast the planet is heating up.) By maintaining our high levels of CO2, we are risking life as we know it on our Earth.

We need to be decreasing the alarmingly high CO2 levels of 409 ppm,  not increasing it by 2 or 3 ppm each year.

Modified: 6 Sep 2019

One Reply to “CO2 Levels”

  1. Terrific overall in in the detail. Very useful information, well written & accessible.


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