Putting aside your awful definition, we really don't know if climate change is a losing political issue. Hillary never campaigned on it. Trump never referred to it. There were no questions about it during the GOP debates, and only one question, without followups, during the 3 Clinton/Trump debates. There were no ads about it. I and many others complained about all of this at the time.
And now Trump's administration is dominated by people determined to roll back all environmental restrictions based on climate change. Suddenly this issue, which Trump never campaigned on or even mentioned, is becoming early one the leading item of his presidency.