As I understand it, human intervention is one of the biggest unknowns in any of these projections. Despite the inadequacy of the global response, there have bee

As I understand it, human intervention is one of the biggest unknowns in any of these projections. Despite the inadequacy of the global response, there have been important human interventions since the 1960s. For example, in the US the EPA was created in 1970 and there were Clean Air Acts prior to that.