
Nukes won’t destroy the planet. All their yields combined don’t measure up to a 1 km asteroid or an average supervolcano, and their radiation and dust is gone in 0.00005% of the remaining time Earth will exist.
The chemical pollution of all our industry washing out to sea will have a bigger impact. All ocean-based animals with shells will die out as oceanic acidity reaches critical levels, though in 0.01% of the remaining time earth will exist shell-based life from freshwater habitats would probablu repopulate them if non-shell-based life doesn’t evolve to fill the same niches first.
There will be trees, flowers, mammals, shellfish, algae, fungi, birds, reptiles, and insects. The Earth from above will look like ocean, forest, desert, and glacier, though the forests may cover less of it for the first 0.01% of the remainder of its existence. We will produce a mass extinction event comparable to the other five, but Earth will still look the same at the scale of a simple drawing.
Many buildings in Africa have their own fossil fuel electric generators. Reliable electricity removes the need for those, which does reduce emissions immediately.
Furthermore, improving people’s lives empowers them to help reduce emissions (or increase them). Reliable electricity frees up labor for things like washing clothes or cooking, which they can then use to work on, for example, regenerative agriculture like the Great Green Wall, which captures CO2 and further reduces the production of CO2 and chemical pollution from extensive farming practices.