Prove it. Someone was there 800,000 years ago to document this, I would expect. Let’s see their data.
Prove it. Someone was there 800,000 years ago to document this, I would expect. Let’s see their data.
I think the question we should really ask is "what was happening 800k years ago that resulted in levels of GHGs as high as today's?"
1.5 million years of climate history revealed after scientists solve mystery of the deep August 9, 2012 - University of CambridgeIncluded in this is a much fuller representation of what happened during the "Mid-Pleistocene Transition" (MPT) -- a major change in Earth's climate system which took place sometime between 1.25 million and 600 thousand years ago. Before the MPT, the alternation between glacial periods of extreme cold, and warmer interglacials, happened at intervals of approximately 41,000 years. After the MPT, the major cycles became much longer, regularly taking 100,000 years. The second pattern of climate cycles is the one we are in now. Interestingly, this change occurred with little or no orbital forcing.
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The resulting picture shows that ice volume has changed much more dramatically than ocean temperatures in response to changes in orbital geometry.
I'm going to go way out on a limb and guess that car exhaust doesn't affect the geometry of the planet's orbit around the sun.
Earth is 4.5 billion years old... this means we would need over 6000 years of accurate weather data to maintain any level os statistical significance on a planetary level