The planet doesn't need saving. Even if we set off every nuke on Earth, in a few hundred thousand years, it would be like nothing ever happened. That's a blink of an eye in the planet's life.
It's about saving us, humanity, about having a clean environment, clean drinking water, reliable food sources, etc. It's about handing the next generation something better than we were handed. It's about setting them up for success. It's about looking forward, not being stuck in the past. Renewables are the energy source of the future. Maybe it takes another 30 years, but don't we want the US to be a leader? Or do we want China and other countries to control that technology?