The topic of global warming has been avoided as a discussion among the field of Republican candidates. Perhaps because according to many research / opinion global warming is often times does not make the list of concerns by Americans.
Writing for Truthout, Dean Baker wrote an opinion piece noting that global warming has been virtually ignored by the press when questions are posed to the candidates about important policies which will be implemented in any of their presidencies.
Contrast the coverage of global warming with the near wall to wall coverage of Ebola back in the fall of 2014, a disease that infected a total of three people in the United States. Or, take the current coverage of ISIS. If we envision a worst case scenario for ISIS, there are probably several thousand times as many lives being put at risk by global warming than will ever be threatened by ISIS.
We got an excellent display of the media's ability to ignore global warning in the two presidential debates that took place after the Paris climate talks. There was not a single question on global warming in either party's debate.