Modern human civilization is fragile — fragile to crop failures, droughts, and extreme weather. We are extremely susceptible to energy and water shortages. We don't fully understand complex, chaotic systems like Earth's climate. And yet, we are rapidly changing the composition of the atmosphere, even though the archeological record shows the difficulty that our ancestors had in adapting to previous rapid climate changes. That seems suicidally reckless. Man-made climate change is a massive problem — the species-threatening challenge of our time. And yet, most people struggle to grasp why it is so important.