Climate (Civ6)

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Climate is a new gameplay mechanic which introduces major changes in Civilization VI: Gathering Storm. It represents a major development in the series where Climate change and the ways players contribute to it will radically alter the later stages of the game.

Introduction

In previous Civilization games climate was represented implicitly in the different 'biomes' (that is, the combination of terrain and terrain features) in the world. For example, Plains and Grassland would represent a temperate or tropical climate, while Tundra and Snow would represent polar climate. Desert and features like the Oasis would represent dry climate. Vegetation (forests and jungles) would also contribute to the climate representation - for example, jungles are only found in warmer and more humid parts of the world, while forests are found in more temperate and colder parts. This implicit representation finds its ultimate demonstration in the rainforest belts in Civilization VI, emulating real-world extra-warm and humid climates which prevail in the equatorial parts of the world.

Gathering Storm, however, ups the ante and introduces a new system in which climate is represented explicitly, as well as implicitly! This is done in two main ways: by creating special disasters which are linked to particular biomes (for example, Blizzards only occur in the colder parts of the world, while Tornadoes occur only in the warm and temperate parts), and by introducing the Climate change system, where players are able to affect the rate of disasters and the melting of the polar caps. The latter may affect radically the later stages of the game and hamper or even cripple entire civilizations!

Mechanics of Climate and Climate Change

Throughout two thirds of the game (until the Modern Era or so) Climate will only be felt through the disasters occurring in the world. The base rate of these doesn't actually depend on climate itself - it is set for each game at its start by the players themselves. Nevertheless, climate is the main condition controlling the rate of most disasters in the game, just like in real life, and when the climate starts to change due to human (player) activity in the later stages of the game, this will be felt by the increased rate of disasters!

The main factor contributing to climate change is CO₂ levels. These are tracked globally and continuously - that means that each player contributes certain amount per turn. He or she may limit their contributions at some point, but this won't alter their previous contributions (at least not until they start running the Carbon Recapture project)! CO₂ is produced mostly by industry, and more specifically by Power generation.

CO₂ levels are also adjusted by the global level of deforestation. This means how many woods, rainforest and marsh features have been removed on the planet throughout the game.

As CO₂ levels increase, the planet starts warming up and the climate patterns start to become increasingly unstable; this leads to climate change's first effect - a general increase in disaster occurrences' chance. Also, there is a greater chance the disasters will be of the most destructive strength (level 5 Hurricane, 1000 years flood, etc.). Finally, after the Antarctic Late Summer Update, a new desertification mechanic comes into play after Climate change progresses past Phase IV: all Storms and Droughts now start removing fertility from tiles instead of adding it.

The second effect of climate change is more subtle, but potentially much more destructive and permanent than disasters. This is the second type of flooding: coastal flooding, which may submerge the coastal land tiles throughout the world! And this is how it goes:

• As the general temperature increases due to elevated CO₂ levels, the polar ice starts to melt (Ice tiles will disappear and be replaced by Ocean tiles);
• Coastal lowland tiles will now get threatened by coastal flooding. Each coastal tile has a rating of 1-3, which shows how soon it will get affected by Climate change: tiles with a rating of 1 are the lowest ones and will get hit first, while those with a rating of 3 will be affected last.
• As Climate change progresses, each several turns land tiles of the appropriate rating (see the chart below) will be affected by flooding or get submerged.
• When the sea level rises by the amount equal to tiles' Coastal ratings, those tiles will be flooded and pillaged (along with whatever happens to be on them, including whole districts with all their buildings). These tiles can still be redeemed, but only after the City that owns them builds the Flood Barrier. Once the sea level rises above the tiles' Coastal ratings, those tiles will be permanently submerged together with improvements and districts on them, and never recoverable! However, the City Center cannot be submerged.

Of course, such disasters will severely limit the use of coasts, especially the flatland-coasts so loved by Cultural Victory seekers! You will have to think twice before placing your districts and important improvements on the coastal lowlands; island settling will be particularly dangerous.

Unfortunately, the main factor in climate change - the rise in CO₂ levels - is tracked worldwide, meaning that all remaining players contribute to it simultaneously. Even if one conscientious player decides to limit his/her CO₂ emissions, another one may decide to recklessly burn fossil fuels and push the temperature rise. The only way the first player may affect this (short of destroying the second player) is by pursuing Climate Accords in the World Congress.

Sources of CO₂

CO₂ contributions are measured in units. There are two main types of sources of CO₂: note, however that each contributes different number of CO₂ units to global levels!

• Power Plants. All three types emit CO₂, but there are considerable differences in the amounts:
  • Coal Power Plants emit the most pollution.
  • Oil Power Plants emit roughly 1/3 the pollution of Coal Power Plants.
  • Nuclear Power Plants are the most environmentally-friendly, emitting roughly 1/10 the pollution of Coal Power Plants. They do, however, carry the risk of Nuclear Accidents.

• Units. All units which consume resources each turn also produce CO₂ but at a reduced rate compared to power plants. This can be further reduced by researching Advanced Power Cells technology.
• Railroads construction. An often-overlooked source of CO₂ is the construction of the ultimate land infrastructure. Every tile of constructed/upgraded Railroad will spend 1 CoalCoal, which does add Pollution, and quite heavy at that! Of course, this is a one-time contribution, and probably cannot compare to long-term power production-related contributions, but still it must be taken into account.

Pollution formulae

The exact pollution amounts are counted on a per-unit of resource consumed basis, rounded down. However, after the Late Antarctic Summer Update units' contributions have been substantially reduced. Now it seems that for means of CO₂ contributions each (military) unit only takes 0.5 resource units! Note that this does not affect the mechanics of resource production flow - there each (military) unit still takes 1 unit of the relevant resource per turn (except the Giant Death Robot which takes 3).

Currently, the different fuel types produce CO₂ as follows (further research needed):

- Coal Coal: ~3.3/unit

- Oil Oil: ~1.9/unit

- Uranium Uranium: ~0.9/unit

Phases of Climate Change

Climate change will progress through seven different phases of severity as increasing numbers of climate change points are earned, affecting the world as shown in the table below. In Phase IV and beyond, Storms and Floods will no longer provide fertility. In Phase V and beyond, desertification will start as Storms and Droughts strip off extra yields granted previously by other Storms, with the chances increasing in later phases.

It is not possible to revert climate change to an earlier phase.

Phase	Points	Sea Level Rise	Coastal Lowland	Polar Ice Melt	Fertility from Storm	Desertification
I	3	+0.5 m	-	10%	Yes	No
II	4	+1.0 m	1 m tiles flooded	20%	Yes	No
III	5	+1.5 m	2 m tiles flooded	30%	Yes	No
IV	6	+2.0 m	1 m tiles submerged	40%	No	No
V	7	+2.5 m	3 m tiles flooded	55%	No	Yes
VI	8	+3.0 m	2 m tiles submerged	70%	No	Yes
VII	9	+3.5 m	3 m tiles submerged	85%	No	Yes

The World Climate Screen

All the info about the new climate system may be visualized on the brand new Climate screen, which may be opened from a special button found in the upper left corner of the game screen. The screen is divided in three tabs; by clicking the Overview tab you will see comprehensive info about the current climate situation, as follows:

• The bar in the upper part of the screen shows the current phase of climate change. As temperature rises and the change progresses, it starts filling with red. Mouse over each phase to see the details of what happens in it.
• On the left-hand side you may see:
  • the current global level of CO₂, adjusted by deforestation level of the planet;
  • how much the global temperature has risen since the Ancient Era (mouse over to also see the deforestation level);
  • what the current climate game setting is.
• On the right-hand side you may see the relevant chances for each type of disaster. They are based on the game setting, and modified by the climate change described to the left. There is a separate section for each type of disaster; mouse over them to get detailed information on how they affect the world.
• At the bottom of the screen you will see the world sea condition: how much polar ice has been lost, and how much has the sea level risen as a consequence (down to the raw number of tiles which are currently flooded or submerged already).
• In the center you will see info about the latest disaster to have struck the known lands. Details about affected tiles, units and population loss will also appear here.

By clicking on the middle tab you will see more detailed info about contributions to CO₂ :

• To the left you will see a diagram of CO2 contributions, which may be distinguished by civilization (the diagram will show the distribution of CO2 contributions by all civilizations which ever contributed), or by resource (the diagram shows the division by the three polluting resources).
• To the right you will see your own civilization's resource contributions to your overall emissions. Underneath the diagram itself you will see how many exactly each resource has contributed - mouse over each one to see the exact contribution in the last turn. This is very useful when determining the exact dynamic of how Power production and Units each contribute to your emissions.

Finally, the right tab of the screen shows a history log of the disasters which have already struck.