I just watched the archive of the stream and I noticed something, something that takes a bit of the science away from our favourite red planet: terraforming parameters that are given from 0 to 100%
Overall, for gameplay, this isn't a bad way to represent things, it gives the player a clear goal, has distinctive milestones, and tells you at a glance how much more you need to work on something to make another happy little world in the sky. But it loses something in the process, something important.
We don't measure the temperature outside as 98% earth-like or 106% too hot, but use degrees C (or F if you live in the 1% of countries who like that). And Mars? Well, today it doesn't have a temperature of 0%, but exists around -60C. While playing the game, as is, you'd get to see a number go up which, you know, it feels nice. Number goes up, hits a value that rounds off in base ten, then it's done. You're happy, the task is complete and you can move on to the next one.
But instead, what if it went from -60C to +15C? On your tracker, instead of a series of 0-100 numbers, you'd get to see it like an incoming weather report. "Average temperature of Mars: -54 degrees today, chance of meteors, sunny." Science. It would teach players about the weather of Mars, how it relates to life on Earth, and just what it means to warm a planet up a few degrees.
Over the course of the game, we'd see it go from absolutely miserable styles of the -120C cold waves to balmy 10C May spring showers to 30C summers of surfing fun.
There is a problem, of course, exact values like this work for temperature. We can relate to temperature, we see it every day, we know how it changes, we know that -10C means wearing a coat and +40C means shorts and sandals. The other values... Well...
- Atmosphere
We've got two ways we like to measure it: Pressure and mass. For pressure, we can choose from a ton of units, pascals being the crowd favourite, but that hardly gets across the scale. Going from Mars' current 600pa to Earth's 101kpa doesn't really have much of an impact (pun impending), but mass? Now there's where we get some science across. See, we've already got 25 teratons of atmosphere on Mars which compared to Earth's 5000tt and you've got yourself a clear delineation between being able to breath on Mars and being able to breath on Earth.
Mars also has a lot less gravity than Earth, which means it takes more mass so you can breathe easy on the surface. Thankfully, there are shortcuts. It only takes 250tt of gas on that planet for the water to stop bubbling out of your blood, which means you'd only need a respirator and some warm clothes to stay alive once you get from 25 to 250. Then if you want to get to Mount Everest-like conditions, you only need 2000tt; still less than Earth. Not exactly comfortable, but certainly you'd be able to go outside without any tools to keep you alive. Past 2500tt and it starts being nicer, like living in the mountains of Tibet rather than dying cold, exhausted, and alone.
In the game, this translates to fine human readable numbers. 25-2500 teratons. You'd see Mars as it is and turn into Mars as you'd want it to be. The tooltips are already long, so it wouldn't suffer much from hovering over it to see a %earth-like value. Since this isn't an idle game where you're constantly wishing you were better at spreadsheets to eek out just that extra bit of time, it's probably fine to hide the less realistic, less flavourful, but easier to read value behind the tooltip.
- Water
The crowd favourite for this one is %surface area. Most of us can already answer the trivia question for, "how much of the Earth's surface is water?" Two thirds (2/3) is the easy answer, more precisely the answer is 71%, but that hardly means anything unless you're making a map. Water on its own isn't particularly meaningful for terraforming. We do need some of it, even deserts have water, but we don't need much, even deserts have life.
Nonetheless, we really like our Martian oceans. They're cool, they're in every visualization, and planets just feel wrong to us unless they've got an ocean. It's why it's needed to win the game in Terraforming Mars, why it spontaneously forms in Spore, and why it's a whole meter you need to fill up here. It's not needed for science, so we can do something much more cool: Precipitation.
How much is it raining on Mars today?
Globally, on Earth, it rains about 990mm a year, but we can round that up to a cool 1000mm, or 100cm, or 1 meter for those who are super into the metric system. Now this one still starts at 0, but rather than having a wishy-washy, "can mean anything," percent-o-meter, it instead gives you a feel for what you're doing to the planet.
Imagine getting to know that you cause the first rain on Mars in a billion years!
You don't even need an event cue for that, just a little tick in the meter from 0mm, to 1mm of rain makes all the difference in the world.
- Vegetation
Now we can get abstract. See, there's no good way to measure diversity or its effects on a planet. We've only got the one example and the way we typically do it is say, "oh well we've got about four trillion tons of carbon biomass living here." We have many attempts we can call on, but we've never had to care about bootstrapping an entire ecology before. Not only do we not have the vocabulary, we don't have the tools. No maths, no equations, no measurements, no numbers to give the player.
Except... Let's talk about why we care about vegetation. A long time ago (like, the 80s or something), two people came up with Daisyworld. A simulation of a simple planet with nothing but white and black flowers on it. The hotter the planet gets, the better white flowers do since they reflect more heat and can stay cool. The colder it gets, the more the black flowers thrive since they absorb the heat. When this happens across the whole planet, it stabilizes: the temperature stays the same even as sunlight gets stronger or weaker. The more diversity you have in the flowers (different shades of grey), the more stable the ecology is. Meaning...
You want diversity and there's only one term there that's actually popular: Extinction. The news has talked about it a bunch, we're losing species. So if the background extinction rate is bad then what we really want is the creation of new species. Thankfully, we already have a term for that: Speciation.
We can import all the plants, lions, lichen, and bacteria we want, but a planet isn't alive unless it's making something new. So my final proposal is something extreme, something far out and new, we tell the player how many new species are popping up on Mars ever year. Every new truly Martian, truly living thing on our terraformed planet that makes it unique to the whole solar system.
Oh sure, the numbers are measured in millions of years, but that's for families. Entire splitting, reforming, twisting branches of the tree of life. We're talking about brand new buds: A new colour of lichen unique to the Martian soil, an new tree found out in reaches where no human has been before, a new bee with blue stripes to better shine in the warm Martian sky.
This one would start at 0 and reach to 20. One new family of life for every family that dies on Earth. A bright new dawn, the redemption of humanity, and all it takes is changing a percentage bar to a real number.

Overall, for gameplay, this isn't a bad way to represent things, it gives the player a clear goal, has distinctive milestones, and tells you at a glance how much more you need to work on something to make another happy little world in the sky. But it loses something in the process, something important.
We don't measure the temperature outside as 98% earth-like or 106% too hot, but use degrees C (or F if you live in the 1% of countries who like that). And Mars? Well, today it doesn't have a temperature of 0%, but exists around -60C. While playing the game, as is, you'd get to see a number go up which, you know, it feels nice. Number goes up, hits a value that rounds off in base ten, then it's done. You're happy, the task is complete and you can move on to the next one.
But instead, what if it went from -60C to +15C? On your tracker, instead of a series of 0-100 numbers, you'd get to see it like an incoming weather report. "Average temperature of Mars: -54 degrees today, chance of meteors, sunny." Science. It would teach players about the weather of Mars, how it relates to life on Earth, and just what it means to warm a planet up a few degrees.
Over the course of the game, we'd see it go from absolutely miserable styles of the -120C cold waves to balmy 10C May spring showers to 30C summers of surfing fun.
There is a problem, of course, exact values like this work for temperature. We can relate to temperature, we see it every day, we know how it changes, we know that -10C means wearing a coat and +40C means shorts and sandals. The other values... Well...
- Atmosphere
We've got two ways we like to measure it: Pressure and mass. For pressure, we can choose from a ton of units, pascals being the crowd favourite, but that hardly gets across the scale. Going from Mars' current 600pa to Earth's 101kpa doesn't really have much of an impact (pun impending), but mass? Now there's where we get some science across. See, we've already got 25 teratons of atmosphere on Mars which compared to Earth's 5000tt and you've got yourself a clear delineation between being able to breath on Mars and being able to breath on Earth.
Mars also has a lot less gravity than Earth, which means it takes more mass so you can breathe easy on the surface. Thankfully, there are shortcuts. It only takes 250tt of gas on that planet for the water to stop bubbling out of your blood, which means you'd only need a respirator and some warm clothes to stay alive once you get from 25 to 250. Then if you want to get to Mount Everest-like conditions, you only need 2000tt; still less than Earth. Not exactly comfortable, but certainly you'd be able to go outside without any tools to keep you alive. Past 2500tt and it starts being nicer, like living in the mountains of Tibet rather than dying cold, exhausted, and alone.
In the game, this translates to fine human readable numbers. 25-2500 teratons. You'd see Mars as it is and turn into Mars as you'd want it to be. The tooltips are already long, so it wouldn't suffer much from hovering over it to see a %earth-like value. Since this isn't an idle game where you're constantly wishing you were better at spreadsheets to eek out just that extra bit of time, it's probably fine to hide the less realistic, less flavourful, but easier to read value behind the tooltip.
- Water
The crowd favourite for this one is %surface area. Most of us can already answer the trivia question for, "how much of the Earth's surface is water?" Two thirds (2/3) is the easy answer, more precisely the answer is 71%, but that hardly means anything unless you're making a map. Water on its own isn't particularly meaningful for terraforming. We do need some of it, even deserts have water, but we don't need much, even deserts have life.
Nonetheless, we really like our Martian oceans. They're cool, they're in every visualization, and planets just feel wrong to us unless they've got an ocean. It's why it's needed to win the game in Terraforming Mars, why it spontaneously forms in Spore, and why it's a whole meter you need to fill up here. It's not needed for science, so we can do something much more cool: Precipitation.
How much is it raining on Mars today?
Globally, on Earth, it rains about 990mm a year, but we can round that up to a cool 1000mm, or 100cm, or 1 meter for those who are super into the metric system. Now this one still starts at 0, but rather than having a wishy-washy, "can mean anything," percent-o-meter, it instead gives you a feel for what you're doing to the planet.
Imagine getting to know that you cause the first rain on Mars in a billion years!
You don't even need an event cue for that, just a little tick in the meter from 0mm, to 1mm of rain makes all the difference in the world.
- Vegetation
Now we can get abstract. See, there's no good way to measure diversity or its effects on a planet. We've only got the one example and the way we typically do it is say, "oh well we've got about four trillion tons of carbon biomass living here." We have many attempts we can call on, but we've never had to care about bootstrapping an entire ecology before. Not only do we not have the vocabulary, we don't have the tools. No maths, no equations, no measurements, no numbers to give the player.
Except... Let's talk about why we care about vegetation. A long time ago (like, the 80s or something), two people came up with Daisyworld. A simulation of a simple planet with nothing but white and black flowers on it. The hotter the planet gets, the better white flowers do since they reflect more heat and can stay cool. The colder it gets, the more the black flowers thrive since they absorb the heat. When this happens across the whole planet, it stabilizes: the temperature stays the same even as sunlight gets stronger or weaker. The more diversity you have in the flowers (different shades of grey), the more stable the ecology is. Meaning...
You want diversity and there's only one term there that's actually popular: Extinction. The news has talked about it a bunch, we're losing species. So if the background extinction rate is bad then what we really want is the creation of new species. Thankfully, we already have a term for that: Speciation.
We can import all the plants, lions, lichen, and bacteria we want, but a planet isn't alive unless it's making something new. So my final proposal is something extreme, something far out and new, we tell the player how many new species are popping up on Mars ever year. Every new truly Martian, truly living thing on our terraformed planet that makes it unique to the whole solar system.
Oh sure, the numbers are measured in millions of years, but that's for families. Entire splitting, reforming, twisting branches of the tree of life. We're talking about brand new buds: A new colour of lichen unique to the Martian soil, an new tree found out in reaches where no human has been before, a new bee with blue stripes to better shine in the warm Martian sky.
This one would start at 0 and reach to 20. One new family of life for every family that dies on Earth. A bright new dawn, the redemption of humanity, and all it takes is changing a percentage bar to a real number.