Pollution Questions

[pdescobar]

I'm trying to understand pollution and global warming. I think I have the basics down, but would appreciate any help. I have done only a cursory look for previous threads on this since search is currently disabled, and if you happen to have a link or two on this, that'd be much appreciated as well.

I. Pollution Generation
As I understand it, pollution is caused by two things in civ3: population and buildings.

Population

• There is no population pollution in towns or cities (size <= 12 in standard rules.)
• When a city hits metro size (13) there is one pollution unit (the little triangle icon) generated. Each additional citizen adds another unit. As an example, at size 22, there would be 10 pollution units from population.
• The only thing which modifies population pollution is the presence of an improvement with the "Removes Pop. Pollution" flag set. In standard rules, the only such improvement is Mass Transit. This caps population pollution at 1 unit. That means a metro of any size with such an improvement will always generate one and only one pollution unit from population.

Buildings

• A building is flagged with the amount of pollution it produces in the editor. This value is the number of pollution units it generates. Examples from standard rules: a Research Lab produces one pollution unit, a Factory produces two pollution units, and the Iron Works produces four pollution units.
• While there are no such buildings in standard rules, an improvement may also be flagged with negative pollution, meaning it causes a small pollution reduction. So, a city with a factory and the Iron Works, gives 6 total pollution units, but if a "Park" is added with a -1 pollution value, a city with all three only produces 5 total pollution units. This means that in a given mod/scenario you may be able to completely eliminate building pollution if your city has enough of these buildings to keep the net value at zero (or under).
• The other modification to building pollution is the "Reduces Bldg. Pollution" flag for an improvement. In standard rules, the Recycling Center has this. Similar to the Mass Transit effect, this caps building pollution at 1.

As I understand it, that's it for pollution generation. The actual amount of shields a city produces is meaningless for pollution generation and all that matters is the population and what buildings there are. You can have a size 50 city generating 300 shields per turn with all manner of factories and other such buildings, but as long as you have the mass transit and the recycling center, that city will never generate more than 2 pollution units per turn.

I'm pretty sure of the above based upon testing and play experience. Corrections requested, though, for any inaccurate or missing information.

II. Pollution Effects
This here, I don't understand at all. To minimize my own confusion, I am reserving the term "pollution" to refer to the things covered in section I; that is the icons in the city screen. The effect it has on a terrain tile will be referred to as an "orange blob." I know that pollution units generated by cities cause the orange blob attack and global warming, but I don't understand how.

1) How do the pollution units (triangle icons) a given city generates correlate into chance of one of that city's tiles gets hit with the orange blob? Is there a simple formula like "every pollution unit adds a 5% chance" and therefore a threshold exists where orange blobs hit a given city every single turn?

2) What about global warming? I have been told that orange blob squares have no direct effect on global warming; they are both simply consequences of the pollution units each city generates. So is global warming simply a random occurance based upon the total number of pollution units generated by the world's cities? Does the place it strikes have any actual significance or is that random too?

3) What about nuclear weapons? Does their use cause any change to the total pollution units generated in the world or increase global warming in any way? Or are they simply another way to create orange blobs?

4) And finally, what does the sun icon actually mean? I understand it first appears the moment a city somewhere in the world generates a pollution unit. What causes it to go darker and what things result when it does?

Thanks for any help on this

 

[Sailorstick]

I have heard that you can make the sun go red when you have launched enough nukes. I think nukes speed up global warming dramatically.

 

[Grille]

Yep, I'm with sailorstick on this one.

by pdescobar:
3) What about nuclear weapons? Does their use cause any change to the total pollution units generated in the world or increase global warming in any way? Or are they simply another way to create orange blobs?

I'm pretty sure that pollution units are added when you use nuclear weapons. They won't show up on any city screen as normal pollution units (triangles), so there seems to be a hidden counter. It's because hard-core terraforming seems to depend on excessive use of those weapons. There are some threads (like Moonsinger's, hbdragon's) in the article section about this topic (I dig up the links later, though I'm sure you know these anyway?).

I *think* that the colour of the "sun" is proportional to the "hidden counter" of pollution units (I'd rather have a number than a sun, showing a percentage chance there), so the sun does not reflect the total amount of pollution units derived from cities only.

Also, I do think that map size must be taken into consideration. But how about number of actual land tiles? Coastal tiles can be affected by global warming, though this is normally rare (and might occur only when nuclear weapons have been used?). How does the game engine allocate a tile that will suffer global warming? If I have no sun at all, but my neighbour has triangles, could my tiles be terraformed? Has anyone had this happen?
Sometimes I see terraforming just outside my borders in foreign territory (though I had always my own sun is this case and could not say if the other civ actually had "metros", factories etc - no nukes being used so far).

 

[Veers]

In Civ II, you could control the onset of global warming - in Civ III, that's not the case. But hey, you're not counted off for it.

 

[Grille]

Moonsinger's nuke-terraforming article

Another thing I'd be interested in: Once a tile (w/o resource) has been terraformed, can it later contain a resource?
Say, a grassland resource-free tile transforms to desert by the time. Could it contain salpeter or oil later, or would there even show up coal (because it was grassland once)?

 

[WillJ]

Pdescobar, you're exactly right about how pollution is generated.

1) I wanna know too!

2) I'm pretty sure that global warming depends on "pollution," not "orange blobs." There have been debates about this, but I think pollution was found to be the winner.

3) Nukes do indeed affect global warming.

4. As said above, I'm pretty sure it depends on pollution (not orange blobs) and nukes. From what I understand, the sun appears (as yellow) when any sort of "pollution value" (which would include nukes) starts. It turns orange as that value increases, but nothing really happens until it hits red. When it turns red, global warming starts. I doubt that the exact formula is currently known to us "peasants." (Although we could probably ask the programmers.) One thing I'd like to know is if when you hit red, have you reached the max? Will the chance of global warming happening to each tile each turn stay the same? Or can it get higher and higher (even though it won't display it to us)?

Originally posted by Grille
Another thing I'd be interested in: Once a tile (w/o resource) has been terraformed, can it later contain a resource?
Say, a grassland resource-free tile transforms to desert by the time. Could it contain salpeter or oil later, or would there even show up coal (because it was grassland once)?

Where resources appear is determined at the start of the game; they aren't really related to the current terrain. This is true with worker actions, global warming, nuking (in vanilla Civ3; nuking doesn't change terrain in PTW), and anything else I've forgotten.

So in your example, desert resources couldn't appear, but grassland ones could.

Since global warming eventually changes ocean squares into desert (IIRC), you could even see fish and whales (or any other water resources that mods might have) "wash up" onto land. (This was actually the subject of one of the SOTD's.)

 

[Grille]

by WillJ:
So in your example, desert resources couldn't appear, but grassland ones could.

Thanks for the info, Will. I was once playing a standart size map (7 ai civs, 70% land, continents, other settings to random) that featured just 3 or so ("clustered") tundra tiles right near an enemy capital on another continent, but no desert. Refining just showed 1 source of oil on the whole map, so I was hoping to "benefit" from global warming. Some desert tiles were created (first one appeared by 1750 or so), but no oil ever showed up on these tiles (fits to your explanation), just one other appeared later on a tundra tile. I continued playing untill 2050 and as far as I understand resource depletion/appearance chances, I could have been lucky enough to have an oil appearance on such a desert tile untill 2050. Anyway, I guess I have to burry that idea.

I doubt that the exact formula is currently known to us "peasants." (Although we could probably ask the programmers.)

Yep, one formula showing chances of global warming and another for the dirt appearance would be pretty nifty. We need more info about this topic.
:tumbsup:

 

[pdescobar]

Originally posted by Grille
Moonsinger's nuke-terraforming article

Interesting. So nukes somehow add to the internal pollution counter for triggering global warming, at least in vanilla civ3. I say vanilla because in current versions of PTW they don't directly transform the land when they hit to prevent the "nuclear terraforming" which was her initial goal.

Another thing I'd be interested in: Once a tile (w/o resource) has been terraformed, can it later contain a resource?
Say, a grassland resource-free tile transforms to desert by the time. Could it contain salpeter or oil later, or would there even show up coal (because it was grassland once)?

As WillJ said, the initial resource placement is determined at game start, which is how you end up with things like rubber on a grassland which was jungle back in 4000BC. However, if you have a disappearance/reappearance of a volatile resource like oil it would be reasonable for it to be able to appear on transformed terrain when it "moves"; I haven't ever tried to test such a thing though. A resource never simply "pops up" on its own though. There will never be more of a resource than was initially generated aside from a special situation that doesn't apply to standard rules.

----------

Manually quoting WillJ
4. As said above, I'm pretty sure it depends on pollution (not orange blobs) and nukes. From what I understand, the sun appears (as yellow) when any sort of "pollution value" (which would include nukes) starts. It turns orange as that value increases, but nothing really happens until it hits red. When it turns red, global warming starts. I doubt that the exact formula is currently known to us "peasants." (Although we could probably ask the programmers.) One thing I'd like to know is if when you hit red, have you reached the max? Will the chance of global warming happening to each tile each turn stay the same? Or can it get higher and higher (even though it won't display it to us)?

I can't believe noone's ever tested this. Back in vanilla, you could get some tile changes due to global warming before the red sun because I would occaisionally get it in my games simply from pollution. FWIW, I have never done anything with nukes except once or twice to see how they worked and have never actually seen the sun go above yellow unless the color change is too subtle and I somehow missed it. I don't think I've seen any global warming at all in PTW though, with my playstyle.


Anyhow, thanks to those who have been able to at least partially answer my questions