Doomerism is a tool to engender compliance. It's how you get people to divert their time and energy from the here and now to some superstitious fixation on the afterlife.

You were not born at the start of the Holocene Extinction. You will not live to see the end of it. You've got a solid 60 years to do your part in your tiny corner of an enormous planet with eight billion others who all got here thanks to the hard work of 30,000 years of prior human labor. There's absolutely no reason to give up before you've even started.