True. Counterintuitively to some, 10 times 5% improvement is 63% improvement overall, not 50%, and 8% improvement on top of 50% improvement is 62% total, not 58%.
That said, 50% reduction is only doable with nuclear energy. Environmentalists who refuse to even discuss it (which, anecdotally, is most of them) aren't really environmentalists at all. They're the PR wing of the "renewables" lobby.
The embodied carbon footprint of just the concrete for a conventional nuclear plant is truly breathtaking.
And there are designs that use bodies of water for cooling and cause thermal pollution problems. Clinton power plant, for example, made the lake unfit for recreation due to an amoeba that causes encephalitis. The locals tried for decades to block that getting built and it was a huge case of 'I told you so.'
Would the locals be OK with a gigantic coal or gas power plant nearby? One with equivalent output? That's (on a macro scale) the real question here. If we are to believe the world is going to pass the point of no return in "12 years", I'd say making a lake unsuitable for recreation ranks pretty low on the list of priorities.
That said, 50% reduction is only doable with nuclear energy. Environmentalists who refuse to even discuss it (which, anecdotally, is most of them) aren't really environmentalists at all. They're the PR wing of the "renewables" lobby.