JoNova (Australia)
More recently, despite rising CO2, there was a cooling of climate for
37 years from 1940 and measurements show no increase in temperature
over the past 17 years.
Global warming, with interruptions, has therefore continued since the
end of the last Ice Age unrelated to CO2 levels. The 600 million year
geological record shows levels of CO2 varied from 200 ppm (0.02%) to
7,000 ppm (0.7%). The significant fall from 7,000 ppm was mainly due to
removal of CO2 in marine skeletal material to form vast limestone
deposits. At that time the ocean could not have been acid otherwise the
limestone would have dissolved.
The present level is near 400 ppm (0.04%) and this could double only
if all the known fossil fuel reserves were used but would still be well
below past high levels of CO2 which did not cause dangerous warming.
Plants evolved in the Cambrian Period when CO2 levels were typically
near 5,000 ppm (0.5%) which provides further evidence that past higher
levels of CO2 did not cause dangerous global warming. "
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