I' can give you the only true answer to your question of "what can I do today to help fight climate change?" But you won't like it and this 'solution' does not preserve society in really any meaningful way, however it does help to address climate change and prevent the entire natural world from dying of heat stroke. So the question becomes, what do you want to save? You can't save everything and trying to do so will only result in you saving nothing.
The answer is large scale industrial sabotage. And when everything grinds to a halt and people start starving to death because of no industrialized food production and various other factors, you will regret the actions. As you and your own family fall victim to violence over food or land because everyone is panicking and trying to survive, you will likely regret it more. But then in 1000 years, there may still be people alive to call you a monster, if they remember you at all.