The math in this article is very interesting, but I do have a question - for anyone.
I wonder if the fact that the Earth’s atmosphere at 1000 MB is bordered on one side by land and sea changes the temperature equation?
On Venus, that same pressure is bordered on two sides by gas.
Most definitely. The earth's water has a number of effects such as thermal inertia, latent heat transfer (global cooling), and global warming by water vapor. The largest effect is warming, but we don't have the thick clouds that venus has that also trap heat there. There are too many different factors to make simple conclusions based on atmospheric pressure.