So why is President Obama addressing climate change through the executive branch? One reason is that the Supreme Court not only held that the Clean Air Act regulates carbon dioxide but also ruled that the EPA must promulgate regulations addressing it. In fact, the President had no choice.
A second reason why the President had no choice to move forward with regulations is Congress won't pass legislation. The reason that Congress won't act is because an incredible 65% of Congressional Republicans outright deny climate science. That's more than enough to paralyze Congress.
More than a few of the deniers declare climate science a hoax or fraud. Others deny temperatures are rising. The "squishes" in the denier caucus concede that temperatures are up, seas are rising, moisture content in the air is increasing but reject that humans releasing large amounts of heat trapping gas into the atmosphere have anything to do with these facts.
Some wiser, "cooler" heads in the Republican party know that its climate position is irresponsible on the merits and is another reason why the GOP is struggling with those younger than 35 and moderate voters. But these cooler heads fear that only decisive election losses will make once again the GOP a responsible policy partner about what to do about our warming world.