Walk, ride a bike/e-bike/electric scooter, or drive an electric vehicle (to not include the last option is unreasonable IMHO). A Nissan Leaf or Chevy Bolt are options, or a Tesla if you want to splurge.
Walk 20 miles twice a day? Is buying a Tesla for $50,000 really better for the environment than driving my old Volvo that gets 30 mpg? After you take into account all the environmental costs associated with constructing a new vehicle?
Do not live 20 miles from work. With that said, you may have extraordinary circumstances that absolutely require you to live 20 miles from your employment. No problem. Statistically, that would place you in the vast minority of people. As long as the massive majority of people that can very realistically replace their commute with public transit and/or other options do so, the problem is solved immediately. There will always be a small minority of people that have to drive a car to work. We are not talking about that tiny minority of people. As I said, we only need 30% and this problem is solved immediately. I repeat, immediately.