First things first, the climate change isn't just a hoax. It's discussable in some points but a very important issue. Trump who was backed up especially in non-coastal areas decided to let the US leave the Paris Climate Agreement which Obama's administration pushed through fastly. Many organizations celebrated a paper containing hazy phrases like we aim to keep the climate 1.5 degree over preindustrial era.
The ideas were great but what happened in these 2 years? Did this agreement per se influence the increase of usage of renewable energy? No. The increase is continuing since it's a good source of energy. Did the agreement per se influence the resources invested in research of more efficient systems? I doubt so. What did the agreement do then? I think that the world wouldn't have cared about the agreement for like 15 years. After that, they'd be like "Oh we already messed up our goals. We need to increase to 2.5 degree but this time it will work, we promise."
Trump woke up the world. He brought up the agreement which was already forgotten even when signed in 2015 - not even ratified by many countries. I believe in supply and demand. I believe that there is a reason that oil prices decreased a lot and were stable in last years. I believe that when electrical cars are improved enough, people will also buy them. For now, they aren't interesting for many people. Expensive and bad quality. Let's see what the next 5 years will bring. And let's see what happens of the promises Musk made.
What must be done NOW though, is to grab the responsibility from the hands of the governments. There is a tremendous amount of solutions to implement "green" decentralized energy. Instead of criticizing Trump, you could have spent your time checking out the market on photovoltaic. You could have tried to invest in wind energy. You could decrease the amount you drive with your car. Climate change starts with our habits. If the people don't invest their energy in green, then the energy will still come from coil in 50 years. Let's be honest, not Trump causes climate change but >7 billion living now. And we will be more. A paper won't do anything itself. But the people can. If you don't take steps yourself in the fight of climate change, you can't be loud when someone else pauses it.