^ You have already posted this two years or so ago. From Milanković cycles (usually taking thousands of years to change) to magnetic fields; nothing explains the sudden rise in such a short time. Nothing than some
other input, if we only had a
hint what this could be
The CO2 cycle is not so well researched indeed, so you may have a point. Still, geological probes of the past do not indicate such a rise of CO2 in the atmosphere as we experience this now. Not in such a short time!
Magnetic fields have changed ever so often, we can see the poles were "inverted" (whatever one sees as the "right" pole configuration) some 30.000 years ago, and again during Viking times, through the positioning of magnetic flux in rocks being used near fire places, raching Curie temperature and thus "freezing" the magnetic field of the earth at the time after cooling.
Theoretically there could be some impact on earth's radiation exposure to the sun when this magnetic field tilts over once more (which is a relatively (geologically spoken) fast process), but it would not have much impact on the temperature afaik.
It has happened a lot of times before, the Earth's crust and outer shells turns with another speed relative to the earth's hot iron core, so the whole setup works like an unbalanced dynamo.