The paradox relating to Milankovitch cycles is that some previous scientific research suggested that, at some eras in the last 800,000 years, rapid increases in temperature preceded similar increases in CO2 concentrations (see the blue arrows in the diagram above). This research suggested that warming at that time might have been caused/triggered initially by the combined effects of Milankovitch Cycles, resulting in a greater warming effect from the sun and that this caused the initial rises in CO2 (released from the oceans) rather than the causality being the other way round. It was suggested that, although CO2 had a warming effect, there was a time-lag of several hundred years between the increased CO2 and the warming effect from it.
In the attached document, I review the recent scientific evidence which suggests that the time-lag between CO2 concentrations and temperature rises might, in fact, be zero, and reaffirms the warming effect of increasing CO2 concentrations. I’ve highlighted the most significant findings in yellow.
Attached document:
i_got_chatting_to_an_agw_denier.docx |
"In the past, it has taken a long time for a warming trend due to Milankovitch cycles to lead to increased CO2 and methane in the atmosphere, partly because it takes thousands of years for melting glaciers and warmer rivers to have any impact on the temperature of the ocean. This has been seized upon by many GW denialists as supposed proof that CO2 does not drive warming cycles. It's a ridiculous position, of course, because the current warming trend is running against the Milankovitch cycle, and CO2 is still a greenhouse gas that has been known since the 19th century to store infrared energy, and we've been pumping more and more of it into the atmosphere."
A pursuasive source linked here at the OSS Foundation argues that we have now entered the Anthropocene Era, where human activity has resulted in irrelevance of natural temperature forcing cycles such as Milankovitch Cycles because human-induced warming (via greenhouse gasses, deforestation and other impacts of human actions) is a much stronger and faster driver of temperature in timescales meaningful to human societies.