I don't get why people say things are going to get worse before they get better. Global warming is a problem of cumulative carbon buildup - it just gets worse b

I don't get why people say things are going to get worse before they get better. Global warming is a problem of cumulative carbon buildup - it just gets worse before it gets worse, and if you hit points that start to trigger feedback loops, then it gets worse no matter what humans do. Though I'd rather not believe it, my suspicion is that it's already much too late in the game to change the outcome.