Both Exxon and Liberty talking their book, but might help to explain Mr Buffett's thinking. Who knows, maybe they're right?

Probably. But a big change like switching, or mostly switching, from fossil fuels to other forms of energy, will take a VERY long time. No matter what we do. For example, there are about 200M vehicles in the USA. Even if 10 million a year switch over to electric, it'll take nearly 30 years to switch (because more than 10 million a year are purchases, so 10M will be electric and 5-6 million will still be ICE, as it progresses). BUT, we haven't even reached the 10M point yet today, we are only at 1.6M right now. So it is entirely possible that the 26 year number is correct, maybe it's 20 years, maybe it's 30 years, but probably in that ballpark. And vehicles are only one example, there are powerplants all across the nation, and those can't be swapped out as easily as a vehicle can, takes years if not decades to get them approved and built and commissioned, etc. There are 150M+ hot water heaters that are inefficient and need to be replaced with heat pump versions that are much more efficient. There are probably 500M+ appliances that are inefficient and need to be switched someday, that'll take 20 or 30 or 40 years best case. And so on for anything that uses energy.