CO2 is CO2 is CO2, no matter the source. Trees, peat bogs, oceans etc make no distinction where they absorb it from.
Maybe CK you can enlighten me on why, during the Pliocene period , 2.5 to 5 million years ago, the CO2 saturation levels in the atmosphere were roughly the same , if not slightly above the levels of today. Not only that, but sea levels were 20 METRES above those seen today. I know this was the period which saw the arrival of Australopithecus and later the first Hominid but no-one has yet found a cave drawing depicting which fossil fuel powered vehicles these early ancestors were flying or driving to cause such an elevated CO2 level commensurate with today's " catastrophic" scenario.