As bad as the environment seems with climate change and other pollution, scientists say humanity has also done a pretty good job of cleaning up past messes.

FILE - In this Sept. 21, 2017, file photo, the Environmental Protection Agency (EPA) Building is shown in Washington. Six former Environmental Protection Agency chiefs are calling for an agency reset after President Donald Trumps regulation-chopping, industry-minded first term. The group is presenting a detailed action plan drafted by former EPA staffers for whoever wins the Nov. 3 presidential election. Most living former EPA heads joined in Wednesday's appeal, with Trumps first EPA chief, Scott Pruitt, being the notable exception. The group said the road map was meant to guide whatever administration the Nov. 3 presidential election puts in place, although many of the proposals are implicitly or explicitly critical of Trump EPA actions.