evidence: Republican U.S. Sen. Ron Johnson cast doubt on whether anything can be done to address the issue, saying the nation can’t afford to spend billions of dollars to "solve a problem that’s not solvable." [...] Milwaukee resident and independent voter Anne Steinberg, 75, said she was shocked to hear Johnson say there’s nothing to be done about climate change. [...] During Friday’s debate, Johnson said "the climate has always changed" while Barnes noted the incumbent has called climate change "bulls—."