Thinking a bit more, there's nothing special about airplanes. The world consumes about 100 million barrels of oil per day. I guess most is transportation, but i

Thinking a bit more, there's nothing special about airplanes. The world consumes about 100 million barrels of oil per day. I guess most is transportation, but in the end it does not matter. There are about 7.5 barrels to a ton, so about 13 million tons daily, which is very nearly 5 GT per year. Each ton of oil produces about pi (3.14) tons of CO2 (of course pi is just a coincidence, but it's easy to remember). So about 15 GT of our worldwide 50 GT greenhouse gas emissions come from burning oil. How are we going to replace that? 5 billion tons per year means about 150 tons per second. At about 40 megajoules/kg, that's 6000 GW. Six thousand large (1 GW) power plants. You say it's fusion or bust. What if we had fusion today? Commercial, economical fusion. As easy to build as natural gas power plants. How are we going to build 6000 large such power plants?