Zoom out buddy, the 2008 financial crisis is a blip. The world's financial system is almost exactly the same as it was pre-2008. Hardly the collapse that made the world stop spinning that doomers have a fetish for. That's not a good example to support your argument.
You fundamentally cannot grasp the concept of doomerism. Doomerism isn't simply observing some first order effect "The oceans will increase by 2 degrees".
Doomerism is observing that first order effect and trying to assert that we should change behavior at a societal level because they above everybody else, can predict what the secondary or tertiary+ effects are for society. "The oceans will increase by 2 degrees, all marine life will perish, hurricanes will make vast swaths of the world uninhabitable. Therefore we should stop eating beef!"
And they are wrong about it every - single - time. Do you need examples?
Society has a long history of ignoring doomers, and the impact? Society is right and Doomers are consistently wrong.
Society keeps going. We have all of history up until the current moment, but from that we understand so far, Doomers have never been right about how disruptive their observations are for society at large. If you want to provide a contradiction to this statement please do so.
Nuclear power doomers -> completely wrong. Fukashima was the latest that proved this
Covid doomers -> wrong. in 50 years covid will be as forgotten as the spanish flu was.
Climate doomers -> wrong. famines are down across the globe and population still growing, still no clear example of the disruption to society or world in a way that is new. For any disruption we can find historical disruptions of the same category with more impact to humans and the world. Floods? More people killed in historical floods and more societies extinguished from them >100 years ago. Fires? More people killed in fires and more cities completely burned down from them >100 years ago.
Overpopulation doomers -> wrong, population still growing, but leveling off and not collapsing
AI doomers -> wrong on both sides so far. no bubble pop, capabilities still advancing, humans are also still relevant
Peak oil doomers -> completely wrong, more oil being discovered, didn't account for technology, didn't account for other forms of energy
With this kind of track record, you'd think that doomers would have enough self reflection to realize that their model of reality is insufficient at predicting outcomes and shut the fuck up, but nope - they just keep on trying to force a square peg into a round hole while annoying everybody around them who are trying to do something to move the needle towards a better life that doesn't involve becoming a vegetable so the earth can heal or whatever.
Compare this against another model of reality: Whatever challenges humans face, when it's dire enough, we will adapt and overcome.
You can backtest this model against all of human history. It would be dishonest to say that this model isn't more accurate so far than whatever model you're using as a doomer.
No need for doomers to virtue signal and lecture everybody about their shitty model of reality that fails to backtest