Though I'm one to question a lot of things and this is my 2 cents. How the hell we know this current changes are completely abnormal? I read about some weird climate anomalies centuries ago and of course there's a lot of evidence that current events are completely abnormal but one question always come to my mind.
What if we're wrong? What if we're being too cooky thinking that by having looked into some evidence that made sense, we're not completely wrong here and current events are just part of a cycle in the planet weather?
Again, I'm questioning but I don't need you guys to present me the proof, I'm aware of it. Just questioning if we're not wrong all along and are here destroying our mental health for nothing. Seems like even by the 1940s standards our generation is being constantly swarmed with problems which we can't fix, which are causing all sort of mental issues due to the complete stress we live in.
This being said, the switch from fossil fuels should be done ASAP, even if we're wrong and it's not causing issues in the environment, they are for sure causing health issues.
So returning to the brick wall - scientists are doing research everywhere contributing to the climate change theory, adding new facts brick by brick. They look the directly measured CO2 levels in the atmosphere and see an alarming trend. The trend has never reproduced previously according to research (both magnitude AND acceleration rate simultaneously, so "cycles" don't explain). They measure ocean temperature. They dig into Antarctic ice and check elements in older layer. And so on, all around the planet. When they encounter something that is hard to quantify, like say global atmosphere temperature over time they estimate. They also check if the existing data fits into an existing theory, and unsurprisingly it does. Unfortunately so far everything fits in the global climate change theory.