Both have their role. Walking is appropriate for local short trips, while bicycles allow you to cover more distance, and is in turn superseded by transit in potential distance covered, while still being a low emissions mode of transportation.
Fewer CO2 emissions is a good goal if you are going to buy a car. Keeping it as long as possible is a better goal.
If the infrastructure allows for it where you live, going car-free is an even better goal for reducing CO2-emissions, and is only one of a long list of benefits of not traveling by car.
Barring that, voting and influencing politicians that can build infrastructure enabling more car-free lives is a good step in the right direction.
Hard to carry a TV on a bicycle, or transport loads to the recycling centre, or drop my kids off at school or any one of a thousand things that occur day to day.
Our world redesigned itself with the invention of cars. Trying to exist without them is very hard for your average family, especially those who live outside cities.
Great, well I have a six year old that needs to get to his school which is about a mile and a half away and I need to get to work 20 mins after which is about three miles in the other direction.
I then also need to do his pickup during my lunch break.
Most people's lives don't work without a car because that's not the society that car ownership created.
It's a town of 90k people. The kind of town that the vast majority of people in the UK live in.
Just out of curiosity how can you transport something large and bulky, that isn't allowed on public transport, let's say furniture, or the remains of a shed you dismantled or any one of a hundred inconvenient loads that occur during your life without a car?
And that someone can't be available every day when I need to do two school runs and an office trip.
That someone can't always be available when the sink springs a leak and I need to go buy some new washers and plumber's mait.
I really question your life experience at this point. If you're single, childless and living in a big city, sure, cars are very unnecessary. For most people this isn't the case