They say the sequel is always worse than the original, but Al Gore’s first film set the bar pretty low. Eleven years ago, “An Inconvenient Truth” hyped global warming by relying more on scare tactics than science. This weekend Mr. Gore is back with “An Inconvenient Sequel: Truth to Power.” If the trailer is any indication, it promises to be more of the same.

The former vice president has a poor record. Over the past 11 years Mr. Gore has suggested that global warming had caused an increase in tornadoes, that Mount Kilimanjaro’s...