What it may look like before an ecological collapse
Collapses occur when your world's stats have changed to the point where your world loses population, biomass, etc.
Collapse
If your world's habitability was at HABITABLE or PARADISE, but it drops to PLANTLIFE, you will receive this notification:
ECOLOGICAL COLLAPSE
[World] is in crisis. As conditions continue to deteriorate, animals and humans alike have become unable to survive on the surface. The survivors huddle in sealed habitations, but if action isn't taken quickly, the next to go will be the remaining plantlife all across the planet. By that point, [World] will be a dead world.
Act quickly.
All population in excess of your Habitation facilities immediately disappears.
If your world's habitability further lowers to BARREN, you will receive this notification:
BIOSPHERE COLLAPSE
[World] is in crisis. As the surface conditions of [World] spin out of control, the planet has been rendered unable to support plant life. Massive die-offs have already begun, and only those plants, animals, and humans already safe in sealed habitations are safe.
[World] has become a lifeless rock.
All biomass will instantly disappear if you have the biomass function enabled. If you have the biospheres function enabled, all species will go extinct. You will get separate extinction notifications for each species.
This is also called Biosphere Collapse if you have the biomass function enabled.
Other Collapses
Note: The following collapses do not give notifications in the game, but will make significant changes to your planet's stats.
If your world's pressure falls below 600 Pa, this will occur:
Aquatic Collapse
All water will change into ice or vapor, depending on your world's temperature. If you go to the 'Water' tab in the Stats Page, it will be blocked by a message basically saying that the pressure is too low, but you can still see the amount that is ice or vapor and the percentages. This collapse is fully reversible.
If your world's pressure further lowers to 0 Pa, this will occur:
Oxygen Collapse
Your world's oxygen will instantly fall to 0 ppm. On the 'Oxygen' tab on the stats page, a message will appear, basically saying that the pressure is too low. If you are playing on world with an extremely high oxygen and almost no pressure (like Europa), you can use this collapse as a quick way to get rid of the oxygen. This collapse is partially reversible, as you will need to increase the oxygen back to it's normal level again.
How to Prevent Collapse
To prevent it, you need to stabilize your planet's stats, which means that growth is +0 per minute on all stats. See this page for tips on how to do that:
- Main article: Building Effects
Additionally, you will need the Sky Farm satellite, otherwise your population will grow so much that they eat all biomass, and when biomass dwindles to the point that your world is no longer habitable, all of that population will instantly die off.
Stabilizing a world on biomass function is very easy, but this is almost impossible to do on biospheres function. This is because with the Biospheres function enabled, oxygen growth can be so slow that it only shows when you have the game calculate change per hour, and doesn't show up when you calculate change per minute. This means leaving the world for a long time will probably lead to collapse.
To prevent collapse on biosphere function, you will probably have to pause the game or visit your world often or culling or conserving some species (that produce or decrease oxygen levels) and countering the effects with random events. If you set a biosphere up correctly you can have stable oxygen levels provided that you check in on it regularly to update the stat changes. Easy way to make a stable biosphere is to have the O2 ppm at what would be most ideal for your plants, then use O2 filters to offset the oxygen they make till the trend becomes negative. Then conserve the plants in a way that they barely produce more oxygen then the O2 filters are removing. Reason why this works, is because once the O2 grows high enough the health of the plants will decrease to the point where the amount of O2 produced is less than the removal rate of the O2 filters leading to a downard trend. This cycle will continue constantly repeat when you check on it frequently (every few days is good).
New Life
If your world's habitability increases to PLANTLIFE, you will receive this notification:
LIFE TAKES ROOT
The first plants have begun to take root on the surface of [World]! Continue your terraforming efforts, and before long we'll be able to introduce animal life, including humans. For now, humanity watches breathlessly as green begins to spread across a formerly dead world.
Biomass/plants can now start growing. If this is the first time this world has reached this habitability level, you will receive 10 GP.
If your world's habitability further increases to HABITABLE, you will receive this notification:
A NEW WORLD
It's been a long time coming, but [World] is finally capable of supporting human life! As your settlers take their first unaided breaths on the surface of [World], a new era of civilization begins.
All that remains is to forge your people into a thriving community, and declare yourself an independent world.
Population will now start growing outside your habitation facilities. If this was the first time your world reached this habitability, you will receive 20 GP.