Another simulation for you.
If we convert all automotive vehicles and power plants to Hydrogen around the globe, given the rate of absorption by the oceans and forests and the rate of expansion of the demand and supply of power, and the rate of conversion how soon would it be before either
a) the by-product levels of carbon-dioxide, nitric acid and hydrogen cyanide in the lower atmosphere achieve a human impact (SciFi reference - various)
a-2) will the atmosphere arrive at a flash-point through another reaction caused by the chemical imbalance? (I remember a SciFi story about that environment - Solar Attack)
b) I lost the option to go to a resort at the Whitsunday islands without having to land in a sea plane wearing a wet suit and scuba gear (normally you might do those things after you arrive ) - say a sea level rise of 2 meters ? is there actually enough ice on earth to do that? if it was all melted what would the levels be? how high would the tides be? (I remember a SciFi story about that environment - waterworld)
c) we run out of habitable space on the surface of the earth because we have dumped so much rubbish (I remember a SciFi story about that environment too - Wall-e)