Tuesday I took up reconsidering the simplest climate model. This time, I'm trying to get rid of the annoying bit of having to know the planet's albedo (reflectivity) in order to find its temperature. Instead, to have some fundamental relationship between temperature and albedo, so that everything in the model is either a fundamental constant (the Stefan-Boltzmann constant), or a fundamental principle (black body radiation, this new albedo-temperature relationship). No great surprise that some readers have already caught on to some of the issues I wanted to talk about.
One, which I'll continue to defer for now, is the fact Arthur mentioned that what this model works with is the earth's blackbody temperature -- its temperature as seen by how much energy it releases to space -- rather than surface temperature. Since we all live somewhere towards the surface, surface temperature is the more interesting number. What the difference between what the model can give us and what we're truly interested in does is to suggest that an important theoretical issue is to develop an understanding of how planetary blackbody temperature relates to surface temperature. Or (scarier) to see if it does relate in any consistent way. But heads up that such a discussion will be coming. Finding these issues, and seeing why they're important, is one of the purposes of the ultra simple models like this.
More issues were brought up by Nick Barnes, who also provides Python code for running your own version (see his first comment for that link). I hope you've spent some time with either the spreadsheet or Nick's Python (use a 2.7 set-up, per Nick's comment on Tuesday) or do so now, as you read this post, and some more as you decide whether and how it makes sense. The spreadsheet is in OpenOffice format (.ods) but I've opened that with MS Excel previously. If you can't, please let me know.
Now, in saying 'issues', I don't mean that there's any terrible comment being made. Rather, it is the truth that even very simple models like this one have some subtleties that you should explore before drawing your conclusions about nature. I'll take up the more physical side of interpretation next, but first let's take a look at some of the technical issues.
21 minutes ago