My point is that Earth has undergone numerous changes of its own making. Forests in the Arctic and Antarctic may not be from the warming periods, but that the planet flipped on its axis. Hot places became come and cold hot. At least 5 ice ages that ground the land down. Not counting near extinctions from asteroids. I've listed 9 catastrophes that never came to be. There is much to be made from human caused global climate change -- not just wealth, but power over others. So, I remain a skeptic. I advocate we expand within the solar system. Colonies on the moon and Mars. Eventual exploitation of the asteroid belt for minerals. Even now, there are plans to use rocket drones to mine near Earth asteroids.