To the first: http://aurora2.pentarch.org/index.php/topic,3871.0.html
Mars
CO2 - 0.227 atm (~61%)
O2 - 0.105 atm (~28%)
N2 - 0.043 atm (11%)
Total: 0.375 atm
Total changes in atmosphere: 0.365 atm
Effort: Minor
Notes: None
I think this is something like the fifth time I've posted this. Magnnus, if you're still hanging around this thread, would you mind editing the OP to include this link?
While i realise that this works, personally i like to get a higher air pressure with less than 1% CO2, because even though aurora doesn't care about it, 60% is far more than lethal :/
Then again that "safe greenhouse gas" is rather gamey anyway, but i like to just imagine that we've used other methods of providing heat, massive areas of heat absorbing terraforming on the surface, maybe space mirrors or something also"
Edit: also there is probably a possible combination of other greenhouse gasses that would work well enough, from wikipedia:
"N2O is a greenhouse gas with tremendous global warming potential . When compared to carbon dioxide (CO2), N2O has 310 times the ability per molecule of gas to trap heat in the atmosphere.." Which amounts to like .20 % compared to that 60% CO2, while i realise it isn't exactly like that since that 300% is based on the vastly higher longevity of NO2 vs CO2, methane also is a good greenhouse gas, a shame Aurora doesn't allow any, since :
" This means that a methane emission will have 25 times the effect on temperature of a carbon dioxide emission of the same mass over the following 100 years. Methane has a large effect for a brief period (a net lifetime of 8.4 years in the atmosphere), whereas carbon dioxide has a small effect for a long period (over 100 years)""Methane is not toxic; however, it is extremely flammable and may form explosive mixtures with air.The concentration of methane at which asphyxiation risk becomes significant is much higher than the 5–15% concentration in a flammable or explosive mixture"
So i imagine that my safe green house gas includes things like methane, nitrus oxide, ozone, water vapor, etc"