Vegetation, Climate, Ecology, and Pollution

[Richard Bruns]

Where?

[Lord God Jinnai]

Offhand? Several of the Hawaiian islands. The desert is of course caused by a high mountain.

[Richard Bruns]

The Hawaiian islands are at 20 degrees North, putting them in the climate zone I described as sub-tropical. That zone gets no NWR adjustment.

[Lord God Jinnai]

Still there can be desrerts in tropical zones if there can be rainforest in temperate zones

[Mark_Everson]

Hi Richard:

The model in general looks really good! I have some reservations that its trying to do to many things, but I think we will only be able to assess how far as the proper amount to go when we see what speed the final thing runs at, and get some feedback from playtesting. Right now I'm focused on how to do the handshaking between the ecological and economic models. So most of my comments will be in that area.

So as I understand it, when the player (or AI) does something like drain a swamp, the square that is modified either becomes part of a nearby relevant ecological province, or starts a new province. If I have it right, then that seems like a practical way to do it. I assume that expressly clearing forest for creating new farmland also falls under this heading. I realize that you have deforestation above, but that seems to be more on the level of incidental deforestation, rather than intentional. I guess I would like to see a few more details on how you would like to see changes like this work. I think that on the square basis we could have the changes be fairly abrupt, like the ones you envision when the boundary of an ecological province shifts. I don't think that would be too bad, seeing as the game is really designed more at the province level, and changing even a single square in a large discontinuous manner shouldn't have a huge effect at the provincial level.

What I need for the economic system is just a way to figure the cost and value of these transformations. So, for example, before the heavy plow there is really not that much incentive for Europeans to cut down their indigenous forest, because farming much of the land is very difficult anyway because of the heavy clay soils. (I can't remember if you were handling heavy vs. light soil types or not, I thought I saw this somewhere in the model) So anyway, in terms of our vegetation types (specifically farm site, and resource site, values), we need to determine some sort of hierarchy for the transformations people can intentionally do. I'll then try and figure out a cost for those transformations, and the Econ system will use those cost/benefit numbers to calculate if the improvements are worth doing. If you do have the soil types in there, then as soon as the heavy plow comes along, there would be huge economic effects as the people start clearing forest to make more farmland. I think whether we want to actually put this sort of detail in the game is debatable at this point, since some players will want it, and others would hate it ("What do you Mean clearing the land does no good!?") .

Irrigation:

At a high level, it seems to me that increased amounts of water should offer diminishing returns. So although irrigation might get you from a water level of 7 to 8 it would seldom be economically worthwhile to do so. Whereas going from 2 up to 5 would be of great benefit... I'd like to hear your thoughts on the complexities/realism trade-offs of putting in something like that. I just afraid that if we don't include a diminishing returns of water effect, you'll end up with irrigation virtually everywhere with high PWR in the model. That just isn't right IMO.

[This message has been edited by Mark_Everson (edited June 11, 2000).]

[Lord God Jinnai]

I agree with mark on irrigation...The only crop i can think of offhand that would need such a high level of irrigation would be rice.

[Richard Bruns]

LGJ:

I have done research on the effects of temperature on net primary productivity and found that my treatment of the effect of climate on farm site numbers is reasonable.

Atmospheric air circulation: The sun heats the air at the equator and in the tropics. The hot air masses then rise, and as the air rises the moisture is forced out of it. This moisture then falls as rain, and the result is that all of the tropical areas have high annual rainfall. These masses of hot dry air fall back to the Earth around 30 degrees latitude. As they fall, they soak up moisture, making the warm temperate climate zones dry areas. The result of this is that tropical climate zones will have a lot of rain and warm temperate zones will have less rain. The NWR rating adjustment reflects this.

Similar circulation patterns with smaller effects take place at higher latitudes. The Sub-Arctic zones have more rain and the arctic zones have less. My redefinition of climate zone latitudes caused a change in the settings; I should have caught this. The NWR adjustments are now:

Tropical: +2
Sub-Tropical: 0
Warm Temperate: -2
Cool Temperate: 0
Sub-Arctic: +1
Arctic: -1
Ice Cap: 0

I will have to experiment with the ecomomic spreadsheet before coming up with a system for dealing with lake and ocean farm sites.

Radiation Treatment Idea:

We define eight radiation levels. Each level represents twice as much radiation or fallout as the previous level. The radiation levels have the following effects:

Causes disease proportional to two to the power of the radiation level.

Reduces the Land and PWR values by the radiation level. This may cause the vegetation to disappear if the new land values are lower than the vegetation requirements. The vegetation is replaced with new vegetation that can survive in the lower land values. If the land value goes to zero, the square becomes a radioactive wasteland where nothing can grow.

An irradiated tile would be assigned a radiation number, and that number would decrease slowly over time. As the radiation number decreases, vegetation can be restored to its original state.

As far as I know, we are not going to track the kind of crops that are growing in the province. I assumed that additional water would enable people to grow different and more productive crops; it is not like you are adding more water to one kind of crop. People are assumed to switch crops based on water availability.

I am working on a revised treatment of water that includes diminishing returns, but for that and many other things I need to experiment with the production function spreadsheet.

[Richard Bruns]

Mark:

I was going to write a big, comprehensivve post replying to all of your last post, but I haven't yet been able to complete the parts that need the econ spreadsheet, so I'll just put some of it here:

Swamps are defined as ecological provinces like all other vegetation types. I thought we wanted to avoid single-square changes, so I had planned on altering the entire province at once. The player would order the swamp province to be cleared and it would be replaced with the new province. That system was designed before I realized how big a single province is. Altering the entire province would be a huge change, and the player might want to make smaller changes. Also, you seem to want to avoid abrupt changes at the province level. If you want to allow square by square changes, I could think of a way to do them. Or, the province could be partially cleared, resulting in terrain that was X% swamp and Y% drained, with Y increasing slowly over time.

Forest clearing would work the same way as swamp clearing. Again, I was thinking of changing the whole province or shifting the border, but square by square changes are possible if you think they should be included or we could do percent forest cover for the province.

The cost of transforming a province or square would have to be defined in the ecology model. There are two costs for clearing: The actual cost of the operation and the opportunity costs of the lost ecosystem. The operation cost is easy to define: The vegetation characteristics could include such a number. The opportunity costs, however, are more interesting and complicated.

Some oppportunity costs can be easily defined. If you destroy a forest you lose the ability to get wood from that square or province. The loss of one type of economic activity is the tangible opportunity cost of altering the terrain. However, there are also non-economic, intangible opportunity costs of destroying natural environments.

We have only recently learned the value of certain natural ecosystems. Wetlands provide a lot of benefits such as water purification and flood control that people didn't know about a hundred years ago. Thus, the percieved opportunity cost of destroying wetlands has risen. This is why the government no longer supports wetland drainage like it used to.

So, in Clash terms, the tech level determines the percieved intangible opportunity cost (PIOC) of destroying the natural terrain. A civ with a low tech level would see zero opportunity cost for draining a big smelly swamp, while a more advanced civ would see a very big opportunity cost in destroying a wetland ecosystem. And to further complicate things, the culture and social conditions of the civ will also impact this percieved opportunity cost.

Regardless of what the civ knows about, there will be a real opportunity cost to terrain alterations, in the form of flooding, erosion, loss of groundwater, etc. These changes will affect the civ over time, as the ecology model calculates the consequences of human actions.

It is impossible to predict exactly what will happen; the ecology model is a chaotic dynamical system with a lot of randomness. We will have to define an average real intangible opportunity cost for destroying natural ecosystem based on what will most likely happen. This will mean putting a cash value on things that are not economic, but we should be able to do it.

To further complicate things, the real opportunity cost of destroying an ecosystem will change based on how many tiles of that ecosystem are on the map. The marginal opportunity cost of losing a terrain type will increase as that terrain becomes less common.

So the PIOC is based on technology, society, and the average marginal real intangible oportunity cost (AMRIOC) of altering the terrain. The exact calculations for AMRIOC and PIOC are a problem best dealt with later.

The cost of the terrain alteration that is entered into the economic calculations is the operation cost plus the tangible opportunity cost plus the PIOC.

The benefits of terrain alteration are also divided into tangible and intangible benefits. The main tangible benefit is an increased number of farm sites. This can easily defined, and the economy model can put a cash value on the farm sites.

There can also be some intangible benefits to altering the terrain. Swamps do breed mosquitoes, and clearing them can reduce disease. These intangible benefits would be calculated in much the same way as the intangible costs of terrain alteration. A civ that did not know how malaria spreads would see little intangible benefit in draining swamps, while the perciened intangible benefit (PIB) of swamp draining would be much higher for a civ that knew about the role of mosquitoes in spreading disease. In some cases, the PIB alone could cause people to alter the terrain.

It may seem like these PIOC and PIB calculations would take a lot of time, but they will not be run for every square. There will be a few dozen terrain types, and all of the intangibles will be the same for every tile of that terrain. Unlike the tangible costs and benefits, they do not depend on the Land and Water values of the terrain. These PIOCs and PIBs only have to be calculated once for the entire civilization and then stored as variables to be accessed when the economic cost/benefit calculations are run. If time is still a problem, they do not have to be recalculated every turn. Some fraction of the intangibles calculations could be run every turn, so the variables for each terrain could be updated every four turns rather than every turn.

The concepts of PIOC and PIB can be used for things other than terrain alterations. Power plants, factories, mills, roads, and farms all have non-economic costs and benefits, as do fertilization and irrigation of farming terrain. I think that some version of this system would make Clash a lot more realistic, dynamic, and fun.

[roquijad]

I've just finished reading the model and I'm posting only to congratulate Richard for his model. It looks really good!

[Richard Bruns]

This post is intended mainly to "bump" this thread up. There has been some recent discussion about the model, and this thread was previously buried on page two. Anyone who is interested in the model should read the Version 2 post and my subsequent posts.

I will also give the progress report on the model:

Version three of the Ecology model is taking a while. The following issues to be worked out:

Disaster Model Cooperation

Month Based ecology model that includes seasonal variations (required because the game turns will last less than a year)

Lake and ocean farming

Increased farm sites with tech level

Swamp/Forest clearing system

Revised Water and Land calculations

Also, I am switching to an object oriented model, which is taking some more time to work out. This is especially true because I am in the middle of learning OO design techniques.

The only big changes to the model will be that it will generate most of the natural disasters, but it will not apply their effects. Also, it will not be responsible for generating the pollution, but it will apply its effects. The Disaster model will generate the pollution and apply the effects of the disasters. Aside from that, Version 2 will probably be pretty close to the default model.

[Richard Bruns]

This post mainly repeats what I posted in the Puzzle vs. Game thread. There will be several possible complexity levels for the ecology model. Creating the detail levels should be a simple matter of adding or taking out certain routines. Note that the higher levels of detail will be more difficult for the player, requiring more management and knowledge.

When I finally finish Version 3, I will tag certain routines to show what detail level they will be in. For example, the PIOC and PIB calculations detailed above would only be in detail level 4, while the deforestation system would be in levels 2 and above. (Even if you don't care about the model, you shouldn't be able to log the same stand of trees for 6,000 years.)

0: No ecology modeling. Ideal for battle scenarios.

1: Like Civ 2. Economic inputs depend on terrain. The terrain never changes naturally, but you can alter it. Ideal for slow computers or low bandwith multiplayer.

2: A "bare bones" version of the current model. A few of the processes are used to make the terrain change in simple ways. Ideal for those who don't care about the model.

3: A simplified version of what I am working on. This will probably end up being the default for a normal game.

4: The full model, with all of the stuff I am working on. Your people will want to manipulate the environment on their own, and you will probably wind up in conflict with them if you want to keep the landscape healthy. (As the immortal leader of the civ, you will be the one stuck with with the long term consequences of their short term selfishness.) This option will probably be chosen by about half a dozen people on the planet, but we will have fun with it.

[Richard Bruns]

LGJ brought up a good point in another thread. He described how the presence of certain types of anumals can affect the development of civilizations. For example, you can't develop cavalry if there are no horses on the continent, and it certainly makes no sense for a city in the arctic to be able to produce elephant mounted troops.

So, we should probably try to define the ranges of some important animals. Hunted animals and domesticated animals kept for food are not very important because those will be handled in an absrtact manner, but draft animals and animals used in war should probably be tracked. These include oxen, donkeys and mules, horses, camels, and elephants.

If a civilization has no access to good draft animals, they will probably not be able to develop intensive agriculture. They will probably turn to hunting and a nomadic lifestyle if there are good hunting grounds, and if they cannot hunt they probably won't advance much, as the agriculture requires so much manual labor that there won't be people available for other things.

We probably can't handle draft animals as an abstraction because technology determines what animals can be used. They had to invent a special collar before horses could be used to plow fields. After they used that collar, they could use horses, which were faster than oxen and plowed fields more effectively. So this means we probably should define the availability of horses, oxen, and mules seperately.

I think that war animals need to be tracked. The availability of horses and camels are definitely important to the way a civilization develops, and if we want to include elephants, their range should be defined as well. I personally don't think we need elephants, because they actually had very minor impact on ancient war. They were not effective and they were not used much.

Do you think we should include dogs and cats? Dogs were important draft animals for the eskimos and they help with farming and other things, but I don't know if this is enough of an impact to justify including them. Cats definitely have an impact on rodent populations and food loss, but again I don't know if this makes them important enought to include. Let me know what you think.

I could define the natural availability of animals by ecological province. Each province would have the following animal related data:
Domesticatable (is that a word?) animals.
Huntable animals.
Oxen
Donkeys
Horses
Camels
? Elephants, Dogs, Cats ?

The original ranges become insignifigamt after a while, however. Once people start domesticating and breeding them, they are spread all over. That aspect of things is best covered in the tech model, however. I'll make a post there to discuss it.

[roquijad]

I liked your idea for horses in the tech thread. Now I realize it is extensible to other animals. I find it great if availability of oxes, mules, etc have an impact on agriculture as well as warfare. Transportation techs would also be very related to the animals you have (if you have).

My list of important tamable animals:
Horses
Camels
Mules
Elephants
Oxes

I agree Elephants didn't play a big role in history, but I'd include for scenario purposes.

[Richard Bruns]

Rodrigo mentioned specials in the other thread, so I looked them up on the webpage. They should do a good job of modeling the wild animals available for taming. I can add routines to the ecology model so it generates these animal specials in some of the squares that form good habitat for the animal.

However, I don't think that these specials should still be on the map after they have been tamed and integrated into the economy. At that point, I believe they should be modeled as province infrastructure.
This may seem odd, but as far as I can tell the equations would be the same. FE the number of horses available would be an important part of the farming and transportation infrastructure, as their presence increases the ability to complete economic activity.

But I'm getting off topic. This should be discussed in the economic thread.

I could generate lots of specials like the wild horses. Once the proper tech is researched, the specials would disappear and become a part of the province infrastructure.

However, I still think that Huntable animals should be treated abstractly. There are just too many of them and they are too widespread to be included as unique specials, so they should still be charactistics of the ecological province. This attribute would be used as a food input in the economic models, as labor turns the game into food. The ecology model would then determine the depletion of the herd in a manner similar to the deforestation checks.

Other domesticatable animals are a bit of a quandary, however. Theoretically, they should be treated like horses; they would start as specials and then become infrastructure. But there are just too many of them. I don't think anyone wants a map littered with wild chicken and wild pig specials. Then there is the fact that most common farm animals were domesticated before 4000 BC, so it would be pointless to include their wild counterparts.

But it does need to be modeled somehow. Cultures with domestic food animals are much less likely to hunt, and their diet will be different. I think there should be some modeling of the amount of farm animals in the province. And it can't be strictly economical, as some areas of the world, like the Americas, don't have animals that can be domesticated as farm animals. I need some help with this one.

A very good aspect of the specials plan is that it makes it much easier to add things like elephants, dogs, and cats. All we have to do is create the special and a couple infrastructure rules. They would simply be another instance of an existing class, so we don't have to do anything special to include them.

By the way, I should be working on adding specials to the third version of the Ecology model. While it wouldn't cover geologic specials like iron, it is the best place to model things like grapes. Mark, could you give me a list of the specials that are associated with the ecology?

I'll discuss the economic aspects more in the proper thread. What do you all think about the ecology/map generation aspect of this topic?

[Richard Bruns]

Please put further discussion in the new thread.