Just posted on Roy Spencer’s blog:
I wouldn’t write off solar variability as a cause yet Roy. Judy Curry and Peter Webster both say you were right to model the ocean down to 1000m despite what Pierrehumbert said. This means extra solar energy gets stored in the ocean on a multi-decadal timescale, because the energy stratifies in layers and can’t escape upwards while the sun is more than averagely active. The sunspot number has on average risen since the little ice age.
Logic says there must be a level of solar activity and cloud cover at which the oceans neither gain nor lose energy. My empirical data study says it is at around 40SSN or its TSI equivalent.
When you integrate the sunspot number as a running total departing from that ocean equilibrium value it tracks SST remarkably well, once you smooth out the internal oscillations in the PDO and AMO. The cumulative count directly represents the additional solar energy being mixed down deeper into the ocean by storms and tidal actions such as those caused by the Moon and Sun and changes in Earth’s length of day. This raises the ocean heat content and thus the sea surface temperature.
If Nir Shaviv’s peer reviewed paper (JGR) on using the oceans as a calorimeter is near the mark, the ~0.25W/m^2 increase in TSI since 1749 gets amplified to ~2W/m^2 (probably via the Svensmark effect of cosmic rays on cloud nucleation, which is solar modulated) and this is enough to explain most of the warming since the LIA, allowing for greater oceanic energy emission as SST rises. Bigger variations in UV may well account for atmospheric chemistry changes to ozone which will modulate the curve.
More discussion here: