> It's hard to imagine how climate change would lead to human extinction, since humans have inhabited such a wide range of environments across the globe for th

> It's hard to imagine how climate change would lead to human extinction, since humans have inhabited such a wide range of environments across the globe for thousands of years, have technology to help cope with extreme climates, and are vary adaptable. What would make every single environment unlivable for humans? I don't believe there is a single climate model that does that. Human life today is mostly maintain with infrastructure (water, food, security, health, etc). A cascade of failure due to climate change can destroy all but very local and small infrastructures. With society eventually returning to a pre-industrial conditions. It is not the end of humanity but the pre-industrial world economy can't support food, water safety and health care for 9 billion people. In pre-industrial era world population were less than 1 billion, we might return to these numbers. That means death of the large majority of human. Not extinction but the biggest threat in human history.