Climate Change in Perspective

by Aert Driessen and John Reid

Below are some graphs of CO2 concentrations and Surface Temperatures on different time scales.

Atmospheric CO2 concentrations (black) and Global Average Temperature (blue) for the last 600 million years

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Southern Hemisphere Sea Surface Temperature derived from isotope ratios (purple) and CO2 concentration from trapped air in ice cores from Epica Dome C in Antarctica

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One Reply to “Climate Change in Perspective”

  1. Thanks John, as I added in a follow-up email, the CO2 draw-down at the end of the Silurian reflects the precipitation of CaCO3 as coral and the very large draw-down at the end of the Carboniferous reflects the march of plant life out of the oceans and onto the land. In terms of Earth’s evolution, we are currently at very low levels of CO2. If it ever gets to 180 ppm (or thereabouts) planet Earth dies.
    As for seawater temps driving atmospheric CO2 levels, rather than the reverse, simply reflects what one learns in high school chemistry classes, namely that CO2 is more soluble in cold water than warm water. The oceans contain some 50 times more CO2 than the atmosphere. The oceans act like a huge equilibrating sink.

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