Yup. Point 2 is an easy sum. Like William I consistently get about two
orders of magnitude every time I try this. Fossil fuels heat the earth on
the order of 100 times more than other fuels via the greenhouse effect.
It's a small term in the big picture. I don't know if urban heating is in
climate models. Perhaps it ought to be as a small scale effect.
Point 1 is a little harder. I'll give it a try.
It seems like point 1 is about input from the stars . That's negligible
compared to input from the moon; you can't walk around in the light of a
clear, moonless night very well compared to a full moon.
As far as I know the moon is not included in climate models. (There are
global tidal models but only lunar gravbity would be represented, I guess.)
The match of apparent area of the sun and moon is convenient here. (It also
makes for an interesting motif in the book and movie 2001, but never mind
that.) For these purposes, let's take the temperature of the moon to be the
same as that of the earth, about 288 K. The sun is at 5800 K. Energy goes as
the fourth power of temperature, so we get about 1/164000 of the sun's
energy density subtending the same solid angle, which scales to about 0.01
W/m^2 at the earth's surface.
So stars would be even less of a concern.
mt
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