Oooo cool game!! I really like this :D
Some feedback I have is to display rates, e.g. how much money I'm earning per day(?), and how much I'm being cost, and then the total result from both of those. Same for population and C02/day.
Could potentially have a number breakdown when hovering, e.g. hovering over Money shows you a list like
"Taxes +12/month
Basketweaving +5/month
Pottery +20/month
Tools -30/month
TOTAL= +7/month"
Or, depending on how many individual upgrades we'll have in the full game, maybe something more compact like
"Income +37/month
Expenses -30/month
TOTAL= +7/month"
Just a suggestion of course as I have no idea what you have planned already!!
Some upgrades also need clearer wording, I'm unsure of the difference between Wealth Tax and Progressive Tax as there is no difference mentioned, Progressive Tax is just cheaper. The different housing options do have descriptions but need clearer wording as I'm also unsure of the pros/cons of each of those. Is Free Housing more a expensive one-time purchase for a bigger longterm population buff? Or is it a high continuous cost every month(?) for a bigger population buff? Etc
Also some upgrades mention "Upgrade Locked: XYZ", which I didn't understand at first to mean buying this upgrade would lock the other upgrade. Initially I thought it meant it needed the mentioned upgrade to be bought first or something. Tbf that one may just be me being silly, but it could still be worth changing it to "Will Lock Upgrade: XYZ"
I also think that having "money" with a dollar sign is a big incongruent with the ice age setting lol. Perhaps "coins" instead? or just "currency" or perhaps something made up like "chips"
All that aside, I really do like this. The balancing act of the tree population is fun, and the way the balanced number of trees to C02 emissions grows as the emissions grow, leading to Bigger Numbers which is both satisfying and also easier to manage with the increased rate of chopping/planting vs the beginning where everythings slow and the tree population needs to be very small to not overwhelm the tiny C02 emissions.
I'm also intrigued at the different tabs for economy and environment, and how it implies the possibility to go too far and end up with a global warming situation like how we have now, and how it could have started with good intentions but spiralled out of control. And how planning for the future is so important even before you think it could ever be an issue.
All in all I really like this and am excited to see where you take this :D