The planet is undergoing a global change in climate that has begun to negatively affect populations and is predicted to accelerate in the coming decades. The human beings now on Earth are the first to exist when the climatic dynamics of the planet are scientifically understood. That understanding makes patently clear that the aggregate effects of human activities have a distinct impact on planetary climate and the way humans will live, if they survive, in the future. This appears to be a tipping point time in human history when future climatic catastrophes that threaten generations of humans might be preventable if governments, institutions, and organizations now take mitigating actions. That suggests that the people currently alive on the planet bear a collective responsibility to address the negative human impact on climate.