Cycling is ten times more important than electric cars for reaching net-zero cities
(theconversation.com)
It's not strictly speaking impossible to bike in below-freezing temperatures, although I'll concede that it's definitely not as fun as it is in spring/summer/autumn-conditions. It requires winter tyres and dressing approximately the same as for comparable winter sports, with more emphasis on warmer dressing for the extremeties. Hands in particular are very exposed when riding in winter, doubling up the gloves is a wise choice.
Note that winter biking doesn't have to replace every trip to be useful - I don't commute by bike in the current conditions, as transit is just a much better alternative during this season. I still use my bike to go shopping and for some other trips, further supporting the possibility of not having to own a car.