Not true.

After the 2005 hurricane season the idea was floated by a few newspaper columnists and scientists but the NOAA is not considering adding a category 6.
[H]e also waxed philosophic on his Oscar-winning climate change documentary “An Inconvenient Truth.” 
“The single most common criticism from skeptics when the film came out focused on the animation showing ocean water flowing into the World Trade Center memorial site. Skeptics called that demagogic and absurd and irresponsible. It happened last October 29th, years ahead of schedule, and the impact of that and many, many other similar events here and around the world has really begun to create a profound shift,” Gore said. 
Gore was referring to Hurricane Sandy, which devastated the East Coast — including New York City — last fall and raised the profile of climate change discourse on the national political scene. 
While scientists generally avoid linking individual extreme weather events to climate change, they agree its effects — such as warmer waters and higher sea levels — can exacerbate storms. 
Those types of events could prove a watershed moment in discussing climate change and its impact, Gore noted. 
“But they’re stronger now,” he said of storms. “The extreme events are more extreme. The hurricane scale used to be 1-5 and now they’re adding a 6. The fingerprint of man-made global warming is all over these storms and extreme weather events.”