Deglaciation periods, such as the one occurring from about 14,000 to 6000 years ago, are estimated to have had ocean heat uptake rates of 12,000-20,000 ZJ (zettajoules). This range of excess energy absorption is 20-30 times greater than the rate of global ocean heat uptake that exists today (Gebbie, 2021).

During the Medieval Warm Period, or Medieval Climate Anomaly (MCA), the ocean heat uptake rates had dipped to about 1500 ZJ.

Today (2000 CE), the global ocean heat uptake has fallen to just 500 ZJ. In other words, even with the warming since 1750, we are still only about one-third of the way back to the ocean heat content values achieved 1000 years ago, when CO2 was 275 ppm.

“…the ~500 ZJ of heat uptake during the modern warming era is just one-third of what is required to reach MCA levels.”

Image Source: Gebbie, 2021

Image Source: Gebbie and Huybers, 2019

Putting ocean heat uptake rates in a temperature context, the top-to-bottom ocean is today (1994-2013) warming at a rate of just 0.0011°C per year (Wunsch, 2018). This is an annual warming rate slightly more than one one-thousandths of a degree.

We are supposed to believe this rate is both alarming and unprecedented. It is neither.

Image Source: Wunsch, 2018