The 2020 lockdown was a good example how simple it actually is. Even after only one month of reduced human activity the planet seemed to catch a short breath again. Of course, to address climate change in any serious manner we'd need a much longer equivalent. Imagine an action worth of 10-years lockdown, or something like that. But since half of the western civilisation refuses to vaccinate or even wear masks, it is hard to imagine they'll cooperate on an issue that takes much much more personal sacrifice.