Winter Speed Workouts: Effort vs Pace

Ok, so I do discuss the idea of getting away from just relying on pace during the winter months, but I do hook you with it so I can discuss some of the physiology of why it matters! A quick 10-minute explanation.
Thanks this was helpful. I’m in week 11, so my speed workouts are all done. I did do most of them on the treadmill. Does this also apply to strength and tempo runs? We have a lot more winter weather coming in this week and I run in the dark, so I don’t like to risk it with ice. I don’t mind slowing down for easy runs, but for tempos I really don’t like to have to stop to navigate surfaces. Is it better to do those on the treadmill?