This game could be fun, but perhaps only if you forget that most are polluting the environment. Not only cars, but planes, ships, trains, bus, etc. For instance a car based in a combustion engine that weighs more than a ton for a single person, and then, it would seem reasonable to criticize it specially when carbon dioxide is creating critical issues like “ocean acidification” (an important search term), smog, and in general a combustion engine places dangerous particles in the air, with some scientific studies ensuring that they are relevant to increase “natural deaths”. Any vulnerable person could be living with several diseases caused directly by pollution.
All of these realities, is leaving climate change alone because it's specially complex, although there are different studies of it. The atmosphere has now obviously much more parts per million of carbon dioxide, so it has changed in its properties. Other conjectures could be simply slowing down actions against the fact of a civilization interacting with natural cycles without knowledge of what could happen after it.
Being aware, any citizen of the world should be responsible with the environment in which lives, but a game like the proposed one might ensure that there's a feeling as if nothing had happening. A behavior comparable to this doesn't solve problems of course. Different environmental damage is being signed by the general connivance and we are rational enough to understand what might mean to the future and new generations, as for our own reputation like sons of the Nature.
If the majority prefers to look toward a false fantasy without consequences, does it make someone less guilty?