New Scientist and Statoil asked specifically what will have the largest near future impact, not what could. Not sure the winner and runner-ups reflect this important distinction
On the positive side of this, I hope that 50 years from now we can look back and realize just what saved us. My leading candidates:
1) LENR (by that I specifically mean the nuclear fusion reactions of nickel with light (normal) hydrogen; if that works out it will surely be the most important thing.
2) If not that, then I'm betting on a supergrid to save us.
When the shit hits the fan, there will be a panicky rush for solutions. Unfortunately only proven technologies will qualify for panic funding. My goal is to have my invention elpipes ready when that moment arrives; see www.elpipe.com