Environmentalists come from two points of view: tree huggers, and home builders.
Tree huggers want to protect the environment because they like primitive, natural things. Either they yearn for older, simpler times, or they think the earth is more important than the people who live here. Home builders, in contrast, want humans to have the best possible place to live. People evolved on the Earth that we know, and so it happens that by keeping the Earth the same as it is now, humans will tend to be more comfortable.
Where these groups differ is when there is a stark choice between Earth and humanity. It is only a tendency that they align. Home builders are perfectly happy to clear an acre of forest land and build a house on it. Tree huggers find it horrible, a failure of humanity. In public policy, home builders are happy to entertain nuclear power, so long as they think the power plants are reasonable safe. Tree huggers hate nuclear power as an unnatural abomination.
A home builder recognizes that we can live in deserts or in dome cities, but would prefer not to. However, they do not rule out such futures if there was some compensation. Home builders would, if pressed, choose a life of ease, health, and luxury even if they had to live in a dome. A tree hugger would never consider it. Ease, health, and luxury are human vices, and we should resist them and focus on stewarding the Earth.
Politicians who cater to environmentalists try to appeal to both kinds of environmentalists. So they talk a lot about emission of poisons, which all environmentalists support. They play down the internally divisive issue of nuclear power.
I think CO2 emission should be a divisive issue of this kind. Tree huggers think the atmosphere should never change, and that is that. If humans are net CO2 emitters, then we should change. Home builders, on the other hand, view the decision more like that of cutting down trees to build a house. They will weigh the benefits of cheap energy and the Industrial Age, versus the costs and risks of a warmer planet.
What kind of environmentalist are you?