Ok, got it. The current environment is controlled by the Auth profile. If you run
pac admin list
You'll get a list of the environments in your tenant. In the list you'll see a different url for each environment.
pac auth create --url <<EnvironmentURL>>
Will authenticate you to a specific environment and create a profile
pac solution list
Will then list the solutions in that environment instead of the default environment.
pac auth list
pac select <<number>>
Can then be used to switch between established profiles, ie. different environments.