[DennisP]

Not necessarily that high with methane fuel. The exhaust is CO2 and water, and you can make it from water, CO2 in the air, and clean energy.

[dangerbird2]

And potentially near-zero emissions with hydrogen/liquid oxygen rockets. Of course, methane rockets probably ends up having lower emissions in practice due to hydrogen typically being produced in methods that emit CO2.

Ultimately, even if we massively increased the rate of rockets being launched, the greenhouse gas impact would be pretty minimal compared to cars, electricity, and cement production.