We have big box stores for pets.
We have semi trucks burning diesel to bring pet food and pet supplies to all parts of the world.
We devote some amount of farm land and livestock to feeding those pets.
It’s interesting when people suggest to reduce global human population but I have never heard anyone suggest to reduce pet populations as a method for combating climate change or for simply reducing resource usage.
The worldwide dog population is estimated to be 900 million.
There are 600 million to 1 billion cats living in the world today.
Trying to be as neutral and objective about this idea as I can:
People who own pets are very emotionally attached to them. Even if pet ownership was the #1 contributing factor to climate change, it would still take an extremely terrible climate for the majority of pet owners to be willing to live without their pets.
If you were to try to introduce some legislation to make this happen, I think that at a minimum and currently owned pets would have to be grandfathered in.
A bit off topic, I have heard some calls to make it mandatory that all pet cats would have to be indoor cats, due to their predation of certain species