My latest update covers some of humanity's ongoing issues with the ecological devastation of Earth after two nuclear wars. Starfire does not really cover this issue, and Starfire Assistant certainly doesn't give the user any way to modify the habitability of a given planet. Therefore, I came up with a house rule covering this specific situation.
After the second nuclear war on Earth destroyed the Coalition and the USSR, I ruled that the population on Earth had been reduced to a medium population (800 population units), and that it could not support than that. The population could still grow, of course, but the Earth couldn't support more than 800 PU's and the excess would have to be shipped out or allowed to die off. As I have the growth turns set to allow population growth every five game turns, that meant that on every fifth turn the Earth's population would pass the limit and the excess would have to be shipped off. Because this is really happening every month, but only being accounted for every five months, I ruled that the human governments would have to pay the full colonization cost of every PTU (Population transport unit) shipped to another planet, but they would not have to use the existing CFN to transport the PTU's to other systems. This was because SA wouldn't allow transports from one government to pick up PU's belonging to another government, and while I could have worked that out, I just figured as long as everyone was paying it would all work out.
This was both an incredible boon to humanity, and an immense drag to their economy at the same time. As I noted in my recent post, the Colonial Union was spending approximately 25% of its monthly income relocating these PU's from Earth to the colonies. And that's base cost for shipping them to the closest, cheapest location. At first, the various human nations were shipping them to outer colony worlds to bolster their populations to the critical 400 PU level, so the cost was much higher. Once a colony reaches that level it can do all sorts of things, including, critically, ship out new colonies from its own population without quickly depleting its population. This was great, and all of the human states quickly built up several systems that could support independent colonization. This gave them an advantage over the other races. For example, the oldest D'Bringi colony has only grown to 341 PU at this point, well short of being able to support additional colonization, while the humans have multiple colonies capable of do that.
Having said that, though, the downside is the incredible cost. Every five months the humans have to deal with another wave of refugees, and their economy, as much as it depended on the influx of new population units, was stressed to the maximum trying to do everything they wanted to do and pay for the refugees. Something had to change.
Finally, outside the game, I became concerned that the humans were inadvertently "gaming the system". Starfire is set up to favor small colonies over large. Larger populations grow more slowly, and larger populations produce less income per person than smaller populations. I recently realized that the humans were taking advantage of that. The Rehorish and the D'Bringi both have much larger populations in terms of numbers of people, and in terms of the size of their largest population centers, but this isn't accurately reflected in a comparison of the production of both sides. So, for within game reasons, and meta reasons, I decided to put an end to the flow of refugees from Earth.
Kurt