Don't shoot the messenger but my take is that environmentalism is much more than just climate change. It just feels like it because carbon emissions is the current topic and perhaps is the most pressing topic because most of the worlds energy is generally carbon based.

The actual issue that environmentalist want solved is less overall production, reduction in all pollution and impact on the environment. And perhaps a bit of wealth redistribution throw in.

If nuclear ever took off meaningfully, the conversation would change and the Greta Thunberg's and Netflix documentaries would be targeted toward nuclear (or whatever takes the place of carbon based fuel) instead. The EVs, solar, wind, batteries and nuclear are great... until they are the last thing standing.

Again don't shoot the messenger! This is just my hot take.