Helion Energy, a US company going through private funding is on track to demonstrate net electricity from nuclear fusion energy in 2024.
Surprised this hasn't taken the Effective Altruism movement, nor had the news of ITER being on track within a few years for EU side demonstration.
Clean, practically unlimited energy, resistant to tail end civilization ending risk like large impact events or volcanic winters.
Desalinization may be feasible for more billions of people in this case.
Nuclear Fusion (unlike fission) has no risk of fallout and byproducts are logistically easy to manage vs alternatives.