Other than some reversals, ice has been melting back ever since the ice age about 4500 years ago. As it melts, more dark earth is exposed to absorb heat from the sun, so the warming accelerates. Warming is due to solar activity. It's not man-made. CO2 is rather insignificant. As for the fluctuations, warming comes first; then the increased CO2 because the warmer water releases it to the atmosphere.
Other than some reversals, ice has been melting back ever since the ice age about 4500 years ago. As it melts, more dark earth is exposed to absorb heat from the sun, so the warming accelerates. Warming is due to solar activity. It's not man-made. CO2 is rather insignificant. As for the fluctuations, warming comes first; then the increased CO2 because the warmer water releases it to the atmosphere.