Okay kiddo, do you know what the word "municipal" means? It's a big word, but it just means something that's related to a town or city, like where we live. And "green" means environmentally friendly, like using less energy, using more renewable resources, and creating less pollution.
So, "green municipalism" is a way of making our towns and cities more environmentally friendly. This means that the people in charge of our towns and cities, like the mayor and other leaders, create rules and plans that help the environment.
For example, they might make more bike lanes or walking paths so that people can use cars less and exercise more. They might also make recycling easier, so people can do it more often instead of throwing things in the trash. They might also choose to use energy from wind or solar power instead of dirty fuels like coal.
Green municipalism is important because it helps protect the earth and all the living things on it, including us! It's like being a good caretaker for our home, where we live and play every day.