A thoughtful article. Thank you!

Scale/magnitude is important to keep in mind. At this point, the effluent of rockets is such a tiny part of what is released into the atmosphere, that it is inconsequential. But the author’s point is valid, because we should start thinking about this, since government takes ages to do anything — and almost always too late.

The issue of satellite debris is the pressing one. We really need rules about that, and a requirement for cleanup. Still, it is important to note that space is inherently full of fast-moving things. An accident of some kind is inevitable: we need to design space systems so that failures are contained, and we need to not react with hysteria when an accident occurs. 30,000 people die in the US every year from car accidents, but when there is a fatality, we don’t scream, “See! Cars are all unsafe! Let’s stop using cars!”

As far as rocket propellants, we are in the early phase of exploration and hopefully settlement. We are “bootstrapping” the process. In the long term, our systems for reaching orbit will be separate from our systems for reaching Mars and the Moon, and then the issue of environmental compatibility should be considered. Right now, during the bootstrapping phase, the propellant should be chosen based on technical expediency.

At present, 2.4 million pounds of CO2 are released into the air every second. (source) A SpaceX rocket’s CO2 release is well below the level of noise in that background.

But come the day of routine space travel on the scale of today’s airline travel, we should have shifted to a sustainable choice of fuels for reaching Earth orbit.