Updated

Talk about an inconvenient truth!

Climate Reality Project, the online home of Al Gore's recent "24 Hours of Reality" broadcast, recently claimed that the event was a whopping success, with 8.6 million viewers.

A back-of-the-envelope analysis of the webcast's real traffic numbers by Watts Up With That -- a website skeptical of the theory of global warming --  suggests that number was the real whopper.

"There may have been about 17,000 dedicated viewers (estimating on the high side) of the program worldwide," Charles Rotter wrote on the website. Watts Up With That's cross-check is based on traffic statistics from popular web trackers Alexa and Quantcast. They do include several adjustments and estimates, the site cautions, and offers an explanation or two for the disparity.

"Maybe the Facebook application put this presentation in people's newsfeeds and they watched inside of Facebook. ... Maybe it showed up in Facebook friends' newsfeeds … Maybe all the users took the alternate path of going directly to Ustream."

"Or maybe, just maybe, there’s a little bit of storytelling going on."

By contrast, the press kit for Ustream, one of the largest web streaming companies on the Internet, notes that it powered more than 3.8 million streams during the 2009 presidential inauguration -- half the online viewers being claimed for Gore's climate talk.

Ustream affirmed Climate Reality's 8.6 million tally Friday night in an email to FoxNews.com.

"The feed pulled in views from our video player that was placed not only on our site but external embeds on a multitude of news sites, blogs and portals including their own site Treehugger, Current TV, Grist and many others over a 24 hour period," Ustream said.

The former vice president and outspoken climate-change defender planned the 24-hour worldwide presentation to combat the country's growing disbelief in his contention that human actions have dramatically shaped the planet's climate and caused a rash of extreme weather.

Eric Young, a spokesman for the Climate Reality Project, refuted reports that the numbers were inflated. He told FoxNews.com that Ustream did indeed drive traffic.

"Our strategy was to bring the event to as many people as possible. We achieved this by partnering with Ustream, whose player was embedded in sites across the web, not just on our homepage," Young said.

"This was in addition to watch-parties in homes, schools and businesses, and the live television broadcast on Current TV."

Ustream's website touts 511,243 views as of late Friday afternoon -- far more than Rotter's analysis, and far less than the company claims.

Individual clips posted to the site detail how many viewers each individual clip had: 13,380 for the final New York clip, 699 for the Rio de Janeiro clip and so on.

However, because Ustream webcasts can be embedded in other websites, Facebook pages and so on overall numbers are hard to track independently.

A "partner highlights" sheet on the Ustream site notes that dozens of live feeds during the Chilean earthquake and subsequent tsunami warning in Hawaii led to more than 4.3 million views -- "making it one of Ustream's largest days ever," the site notes.