Fewer people have starved since the Columbian Exchange began, but the diversity of life on Earth has diminished dramatically, and planting crops where they don't belong has hurt the environment. So on the whole, should we be grateful for the Columbian Exchange? And should we work to continue and deepen its legacy of globalism and monoculture? Crosby didn't think we were better off. The Columbian Exchange has included man, and he has changed the old and new world, sometimes inadvertently, sometimes intentionally, often brutally. It is possible that he and the plants and animals he brings with him have caused the extinction of more species of life forms in the last 400 years than the usual processes of evolution might kill off in a million. The Columbian Exchange has left us with not a richer, but a more impoverished genetic pool, and we, all of life on the planet, are the less for Columbus, and the impoverishment will increase.