Al Gore has slammed Fox News for "consistently deliver[ing] false and misleading information" about climate change, after a leaked email showed pressure from a network exec to undermine the findings of climate scientists.

Liberal watchdog group MediaMatters reported Wednesday that the Washington managing editor of Fox News, Bill Sammon, sent an email to staffers requesting that they report on rising temperatures as being based on "questionable" data, even when they are not.

"Given the controversy over the veracity of climate change data ... we should refrain from asserting that the planet has warmed (or cooled) in any given period without IMMEDIATELY pointing out that such theories are based upon data that critics have called into question," Sammon urged.

"But there's no legitimate debate: the planet is warming," Gore, one of the world's leading environmental activists, wrote on his blog. "Moreover, man-made global warming pollution is the principal cause."

Gore continued: "Fox News has consistently delivered false and misleading information to its viewers about the climate crisis. The leaked emails now suggest that this bias comes directly from the executives responsible for their news coverage."

Sammon reportedly issued the instructions less than 15 minutes after Fox News correspondent Wendell Goler noted that the United Nations' World Meteorological Organization announced that 2000-2009 was "on track to be the warmest [decade] on record."

"2000 to 2009 [is] expected to turn out to be the warmest decade on record," Goler reported during the 2009 Copenhagen climate change summit. "2009 itself was about the fifth warmest year. There was extreme drought in Africa, extreme heat in India and northern China."

"But it's the decade trend that has scientists concerned because 2000 to 2009 [is] warmer than the 1990s, warmer than the 1980s," he said.

"Contrary to Sammon's email, the increase in global temperatures over the last half-century is an established fact," reports MediaMatters. "As the National Climatic Data Center explains, the warming trend 'is apparent in all of the independent methods of calculating global temperature change' and 'is also confirmed by other independent observations.'"

-- With an earlier report by David Edwards