The short answer

“Because, underneath all of this is the real truth we have been avoiding: climate change isn’t an “issue” to add to the list of things to worry about, next to health care and taxes. It is a civilizational wake-up call. A powerful message—spoken in the language of fires, floods, droughts, and extinctions—telling us that we need an entirely new economic model and a new way of sharing this planet. Telling us that we need to evolve.” 
― Naomi Klein, This Changes Everything: Capitalism vs. the Climate