What Causes Global Warming (and Many Other Questions)?

[Sorenroy]

Hey all, I've been looking at older threads on global warming and have a couple of questions I don't think have yet been answered.

First, where exactly does global warming come from? I know it comes from pollution, but I'm not sure if that only includes the pollution on the ground that eliminates a tiles productivity (i.e.: from volcanoes, cities, and nuclear weapons/meltdowns) or if it also includes the pollution shown in the cities as hazard symbols. For example, if I made sure to clean up the pollution with workers as soon as it occurred, would I ever have global warming effect any tiles? Or for that to happen would I need to prevent any cities on the map from going over population 12 and having any pollution causing buildings?

Second, is there any lead before global warming starts to occur? I know that for cities that enter disorder, you get a turn to fix it before there is a chance any of your buildings are destroyed. Is there something similar for pollution and global warming? If I keep pollution low enough and clear it as soon as it pops up, will I ever have tiles flip?

Third, how does map size effect global warming? If I'm playing on a tiny map vs. a huge map, what is the difference (if any) in the amount of pollution needed for global warming to start? Or does it start at the same point and just get diluted by the number of tiles?

Fourth, why is it that forests have priority when it comes to pollution and is there some way to change that? I have seen it both in the games I've played myself and in other forum posts that forests get flipped before any other types of terrain are effected, but looking in the editor and civilopedia, I don't see any reference to why this is. Is this hard coded in the game or is there some way to change it? If I go into the editor and change the tiles that are effected, is there some type of order for what is effected first? For example, let's say I make global warming turn coast into ocean and desert into mountains even though neither of those tiles are normally effected, is there some order to them or would they just have a 50-50 shot of either occurring?

Fifth and finally, what happens to tile improvements/cities/resources if the underlying tile is changed? I know there is one scenario where this would naturally happen in the game (marsh into coast), but I've never gotten to the point where that occurs (either blocked by other forest on the map or cleared before pollution can get to it). What happens to roads, mines, and irrigation, and any resources that happen to be on the tile when a tile is transformed into another tile that cannot support those improvements/resources? Does a tile turning into a volcano cause that volcano to specially keep improvements until pillaged, or do they vanish upon change? Also, if a tile with a city on it is turned into a tile that cannot support cities, what happens to the city/tile? Are tiles with cities on them left unchanged, are the cities destroyed, or are the cities left intact with changed base tile until raised?

Sorry for posting so many questions in a single topic, but I figure is someone in the future is looking back for answers to what exactly pollution does and how it is caused, they'd rather find the answers all in one spot (at least, that's what I was looking for searching old threads myself). If you only know the answer to one or two things, please still post them. Answers to some are better than answers to none. Also, I'll try to update here if I happen to stumble upon the answers to any of these while I'm playing in the future. Thanks!

 

[jarred!]

1. My understanding is that no player could build any hospitals nor any other pollution causing buildings in order to stop Global Warming. The pollution that a metro generates will cause tiles to become polluted (within that metro's BFC), and you'll have to clean the tile before it becomes productive again. Global warming is a global stat, and I assume the game takes into account all the pollution from all pollution-causing metros in the game (some math involving the hazard symbols of all metros).

2. City disorders can generally be fixed before they occur. It's useful to go through your cities every turn and make sure your citizens aren't unhappy. OTOH, when you build pollution-causing buildings, you're signing up for pollution.

3. The game takes map size into account for other mechanisms (i.e. corruption and tech cost), so I assume it does for GW. Having 100 metros with coal plants on a tiny map is going to be worse than 100 on a huge map.

4. Not sure about the editing aspects. Forests die off to reveal the underlying terrain (you can replant them!), and then: grassland>plains>desert.
A desert on a river is a floodplain, so GW can give you extra food sometimes.

5. Nothing, grassland, plains and desert can have the same operations done to each of them.
I wasn't aware marsh becomes coast. You say it hasn't happened to you because of a forest in the way, but both are overlays, and would not exist together. AFAIK, none of the examples you give occur naturally in the unmodded epic game.

 

[Sorenroy]

Thanks for the answers! In reference to number five, when I say that the transition of marsh to coast was blocked by forest, I mean that I have always had forest on the map when their is global warming and prioritized replanting if the number of forests I had was getting low, not that the forest was on top of a marsh tile directly. The fact that marsh can turn to coast is in the editor, it's just that I've never seen it happen.

Also, from what I've seen creating a custom world with pollution already on it, pollution does not seem to have an impact on global warming, only population and pollution-causing buildings do. Although I'm not sure what was up with that testing as even with a red-orange sun I couldn't get a marsh world to turn to coast. I guess I'll have to do some more experimenting with that.

 

[justanick]

Those are some good questions. I wish i had definitive answers to them but all we have seems to be assumptions. I also have a question to add:

Is planting forests on unused tiles an effective strategy to avoid global warming becoming a relevant problem?

First, where exactly does global warming come from? I know it comes from pollution, but I'm not sure if that only includes the pollution on the ground that eliminates a tiles productivity (i.e.: from volcanoes, cities, and nuclear weapons/meltdowns) or if it also includes the pollution shown in the cities as hazard symbols. For example, if I made sure to clean up the pollution with workers as soon as it occurred, would I ever have global warming effect any tiles? Or for that to happen would I need to prevent any cities on the map from going over population 12 and having any pollution causing buildings?

Vulcanoes should not matter, do they?

The hazard symbols in the developed cities seems to determine the probability of pollution to occur. It may be 1% per turn per hazard symbol. Each city can only produce (up to) 1 pollution per turn.

My guess would be the following: Each time a tile is polluted by any of the civilizations a counter is increased by 1. In case of nuclear incidents the count is increased by one for each tile polluted. The counter divided by the amount of tiles on the map determines the symbol for global warming.

In most games pollution becomes a relevant problem, but global warming does not amount to something significant.

 

[tjs282]

My understanding has always been that the 'visible pollution' on tiles (rendering that tile unusable) and the late-game alterations of those terrain-types which have 'global warming' (GW)-effects set in the editor (total risk indicated by the sun-symbol in the lower-right info-box) are actually two separate outcomes — one local, the other global — rather than that the former directly leads to the latter.

If that's the case, then it would make sense that the risks of occurrence of both of those outcomes would be calculated (separately) based on the 'pollution-triangles' generated by (industrial) buildings and (metropolitan) population: but whereas visible pollution from industry/population can only happen in the BFC-tiles of a city with 'pollution-triangles', GW would be related to the sum total of all the buildings/population on the map, and could affect any tile. (This would also be a reasonable simulation of the 'real-world' effects of industrial-smog/-effluent [local], vs. those of AGW [global])

I believe the player only gets the 'Global warming has altered this terrain!' notification for tiles within their own borders, though — so even if the GW-problem was rampant, a smaller (human) empire would still tend to see fewer of those notifications than a larger one.

Visible pollution can of course also be generated by volcanic eruptions and nuclear weapon use, but (again according to my understanding) neither volcanoes nor nuke-usage would directly contribute to the GW-risk. However, the (flat) terrain-alterations caused by nukes do certainly also follow the same 'degeneration-sequence' as set for GW, i.e. 'drying' from Grass -> Plains -> Desert (possibly nukes do also cause devegetation of Jungle/Forest — but by the time I'm getting nuked by the AI, I don't usually have any of that terrain left adjacent to any of my nuke-worthy cities!).

Vulcanoes should not matter, do they?

My understanding above, may well be wrong. If anyone has ever seen the sun-symbol appearing in the early game — after at least one eruption, but before Shakespeare's and/or any Industrial-era buildings have been built — that would pretty much confirm that it is the (total) polluted tiles (in this case, from erupted Volcanoes) which increases the GW-risk.

Fifth and finally, what happens to tile improvements/cities/resources if the underlying tile is changed? I know there is one scenario where this would naturally happen in the game (marsh into coast), but I've never gotten to the point where that occurs (either blocked by other forest on the map or cleared before pollution can get to it). What happens to roads, mines, and irrigation, and any resources that happen to be on the tile when a tile is transformed into another tile that cannot support those improvements/resources? Does a tile turning into a volcano cause that volcano to specially keep improvements until pillaged, or do they vanish upon change? Also, if a tile with a city on it is turned into a tile that cannot support cities, what happens to the city/tile? Are tiles with cities on them left unchanged, are the cities destroyed, or are the cities left intact with changed base tile until raised?

I'm not sure what happens if GW degrades a terrain-type which allows a specific Worker-job/ terrain-improvement, to a type which doesn't.

That's irrelevant in the epic game, though, since (apart from Floodplains, which don't degrade) all flat non-vegetated tiles already allow all the Worker-jobs — and Marsh cannot be Settled in the first place, so there would never be an issue of it degrading after a city was built on it. And nuke-usage wipes out all terrain-improvements anyway. Also, AFAIK, town-tiles are not subject to GW-degradation; but even if they were, that would also have no effect in the epic game, since all towns give (at least) 2 food + 1 shield, regardless of what terrain they were founded on, and a newly-built town clears Forest/Jungle vegetation down to the base-terrain.

So this would only be an issue in mods with altered terrain-properties and degradation-progressions (e.g. a fantasy-based mod where increasing 'magic usage' caused Volcanoes to spontaneously appear on flat terrain!). As far as that goes, one would hope that the Firaxis-programmers remembered to include a 'Worker-jobs/ terrain-improvements allowed in [degraded] terrain-type?' query in their terrain-degradation procedure, so that any now 'illegal' terrain-improvements would be removed automatically — but assuming that they did may be rather, umm, optimistic...

The fact that marsh can turn to coast is in the editor, it's just that I've never seen it happen.

IIRC, I read somewhere that this transition is bugged, although I can't remember where I read this, nor why it should be so.

Although I do know that the Editor won't allow a 'Land' unit to be upgraded to a 'Sea' or 'Air' unit*, so it might be that something similar is happening here: i.e. a 'Land' tile cannot degrade to a 'Water' tile.

*

Spoiler How I found this out :

In my mod-in-progress, I wanted to get Cavalry out of the build-queue in the late Industrial era without turning them into Tanks, so I was thinking to have them upgrade to Fighters instead, to keep that common 'fast attack/reconnaissance' quality. But the Editor wouldn't let me...

So in the end, I decided to just have Cavs be obsoleted by Tanks, i.e. setting the last unit in the Chariot–Cavalry line (Sipahi?) as 'Upgrades to: Tank' but leaving the 'Upgrade' unit-action un-checked.

Is planting forests on unused tiles an effective strategy to avoid global warming becoming a relevant problem?

Again, I believe that vegetated tiles are more likely to be hit by GW than the non-vegetated flatland-tiles: if that's the case, then yes, extensive Foresting (e.g. in Tundra-zones) should indeed 'prevent' some if not all of the potential dehydration of the flat tiles.

And since the map's humidity-setting primarily affects the number of 'naturally' vegetated tiles at the start of the game, GW should also be a more noticeable problem (in terms of loss of tile-fertility) on Dry compared to Wet maps — and/or in mods where the 'Plant Forest' Worker-job has been disabled.

 

[Civinator]

Those are some good questions. I wish i had definitive answers to them but all we have seems to be assumptions.

Besides assumptions we have one written statement by Firaxis and a confirmation from the programmers to a question done by the modder warpstorm:

In the Civ3ConquestsEdit stands the following:



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The modder warpstorm posted the following:

https://forums.civfanatics.com/thre...lobal-warming-change-tiles.46924/#post-832216

Pollution on the ground does not effect global warming in the least. I know this because I've made test cases to test exactly this fact. I then asked Firaxis how it actually worked, and they said that it is the number of pollution 'triangles' along with the amount of nukage in your cities that cause both global warming and pollution tiles on the ground. Now, having said that, pollution on the ground should be cleaned up because it will eventually degrade the tile it is on.

https://forums.civfanatics.com/thre...warming-change-tiles.46924/page-2#post-833255

yes, it does degrade that tile (separately from global warming effects) and, yes, this was discovered by testing (then confirmation from the programmers).

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So according to these sources it seems tile pollution and global warming are different factors in Civ 3, but both factors can trigger a transformation of terrain: The tile pollution a transformation of the tile it is placed on, the global warming a transformation of random tiles on the map.

I cannot contribute deeper own experiences to this item, as I always considered pollution and global warming and the annoying micromanaging that is needed to deal with them, as a very 'unfun element' of Civ 3 and eliminated both of them in my mod CCM.

 

[Sorenroy]

Thanks for directing me to that older thread! I had not even realized that pollution and global warming were calculated differently or that tiles could degrade over time. Also, the fact that nuclear weapons have a permanent effect on the world makes them much more dangerous. I had always assumed the increase in global warming caused by all-out AI nuclear wars would go away after the land was cleared of pollution and resettled.

I guess all that leads to one last question, does the "Pollution Effect" in the editor also change what happens during global warming? I mean, if it changes what a tile will turn into if pollution is not cleared from it, does it also effect what a tile will turn into if it is changed by global warming, or are those two changes done completely separately? If I edit in the pollution effect of turning grassland into tundra, will global warming also cause that effect?

IIRC, I read somewhere that [the transition between marsh and coast] is bugged, although I can't remember where I read this, nor why it should be so.

Good to know. I was wondering if I was doing something wrong because nothing was happening to the marsh tiles on my testing map.

Is planting forests on unused tiles an effective strategy to avoid global warming becoming a relevant problem?

Absolutely. I have never seen non-"Forest to Base Terrain" global warming because I always keep a good percentage of tiles forested. On some later maps that have seen massive nuclear holocaust AI vs. AI wars where I am only at 5-10 percent of the land area I will have five or even more forests revert to their bases each turn, but never anything else.

 

[tjs282]

I guess all that leads to one last question, does the "Pollution Effect" in the editor also change what happens during global warming? I mean, if it changes what a tile will turn into if pollution is not cleared from it, does it also effect what a tile will turn into if it is changed by global warming, or are those two changes done completely separately? If I edit in the pollution effect of turning grassland into tundra, will global warming also cause that effect?

Yes. The same terrain-degradation sequence is applied, regardless of whether it's caused by nuke-damage, global warming transformation, or -- as I've just learned from this thread* -- 'industrial' pollution damage as well.

*(Thanks for this thread, BTW: prior to reading it, I didn't know this)

 

[Zefyrinus]

As has been said, the marsh>coast thing is broken and can't actually happen. Someone once posted a chart of which terrains can turn into what. I'll see if I have that saved somewhere on my old computer...