In Reply to: re: Climate Change posted by Postman Pat on December 10, 2015 at 10:15:51:
The record goes back hundreds of thousands of years for historical records of CO2 measured in ice cores. The highest previous concentration was 298 ppm 330,000 years ago but more normal concentrations at or below 260 ppm with lowest values of 170 ppm between 660,000 and 670,000 years ago. The current 400 ppm have never been seen and it's increasing steadily.
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