A couple of basic questions for Bob Tisdale.

Bob Tisdale has added a new post to the Watts Up With That (WUWT) site, in which he makes a a quick comment about the PAGES continental temperature reconstructions. In this post he comments that “but as I’ve been illustrating and discussing for 4 years, ocean heat content data and satellite-era sea surface temperature indicate Mother Nature is responsible for the warming of the global oceans” and he links to a PDF copy of a presentation about the man-made global warming challenge.

I had a look through this presentation and I have a couple of basic questions for Bob Tisdale. He may never find this site, but feel free to point it out to him and he’s welcome to clarify my understanding of what he proposes. In this presentation, he shows sea surface temperatures for 4 different regions. Some seem to show rises in temperature, one definitely seems to be flat (although noisy). What Bod Tisdale then goes on to claim (if I’ve interpreted it correctly) is that the rises in sea surface temperature, and then the land and atmosphere I presume, are driven by ENSO variations. His claim seems to be that energy in the ocean is brought to the surface where it heats the sea surface and then the land and atmosphere. Okay, there’s lots of energy in the ocean, so this might be plausible. However, there’s no net global warming (according to Bob Tisdale) so the question I have is

1. If all the warming we’ve been measuring is driven by ENSO variations in which energy from the oceans acts to heat the sea surface, the land and the atmosphere, the heat content of the oceans must be decreasing. Why do measurement suggest that the ocean heat content has been rising?

The other thought I had about Bob Tisdale’s suggestion is that the Earth will always tend towards an equilibrium in which the energy escaping back into space balances that received from the Sun. If the atmosphere is not playing any significant role in global warming (i.e, it’s influence has essentially been constant for millenia), then the amount of energy we lose is determined by the surface temperature of the planet. If everything is simply due to natural variations, then presumably the surface temperature must be varying from a value that is below the equilibrium value to one that is above the equilibrium value. Given that most studies indicate that the current temperature is higher than it has been for most of the last 1400 (or more) years, we must – currently – have a surface temperature that is above the equilibrium temperature. My next question for Bob Tisdale is then

2. If our current surface temperature is above the equilibrium temperature, we should – at the moment – be losing more energy into space than we receive from the Sun. Why do satellite measurements indicate that for the last few decades we’ve been receiving more energy from the Sun than we lose into space?

These are two genuine questions that I would be happy for Bob Tisdale to answer. I’ll be honest and say that I don’t see how his suggestion is consistent with observations of the ocean heat content and the global energy imbalance, but I more than willing to be convinced otherwise.