What was the biggest climate change event in the last one million years on earth? I would say it was the melting of the vast ice sheets covering much of the northern hemisphere. When this happened an area much larger than today's Alaska disappeared as sea level rose from all of the melted glacial ice.
Although there were small groups of humans around for the tail-end of the Ice Age the knowledge of the fact that there WAS an Ice Age became lost to human memory and knowledge. We simply forgot that it ever happened at all and the Great Ice Age was only rediscovered in the 1850's. And of course those that first proposed that much of the planet was shaped by moving ice were laughed at by "deniers" who believed the earth was shaped by the Biblical Flood. Some would say the science of climate change started with those debates. We are only beginning to learn how the climate effects our world and our lives. Stay tuned in for more....