The climate crisis couldn't be solved with such a small sum of money
852 billion isn't 'a small sum of money'. And thats just OpenAI - add to it what Google, MS, Meta etc have spent and I'll bet you'll get close.
addressing world hunger would decimate our economies
What will decimate the global economy is the correction that will happen when either AI proves to be a folly or investors realise they'll never recoup what they've paid out. Or when theres mass unemployment cos AI has taken all the human jobs. We're cooked whichever way it goes.