Do ice core records showing that warming preceded CO2 rise cast doubt on greenhouse warming?
Antarctic ice core records dating back 800,000 years suggest that increases in carbon dioxide lagged behind increases in temperature by a couple of hundred years. This observation has been used by some to incorrectly claim that modern CO2 emissions cannot be causing a rise in temperature. This misconception is based on the false dichotomy that warming is either driven by CO2 or CO2 is driven by warming. In reality, both are true.
In the past, warming was driven by variations in Earth’s orbit and tilt, resulting in changes in solar energy reaching Earth which caused some initial warming. This triggered the release of CO2 from oceans which caused additional warming. Thus, while CO2 first increased due to warming, the extra CO2 also caused additional warming.
Recent anthropogenic global warming cannot be explained by natural cycles, which are in their cooling phase.