Appearing on the October 5 episode of "Real Time with Bill Maher," author and environmentalist Bill McKibben cautioned Maher's panel on the effects of climate change on Earth's polar regions: "We broke the Arctic."

While on the show, McKibben expressed his frustration with those who perpetuate the idea that scientists remain divided about the existence or human origin of climate change. He says, "Scientists figured it out. That's why we have scientists."

McKibben cites 2012's record temperatures and severe drought as confirmation of what NASA climate scientist James Hansen has called a "planetary emergency."

Indeed, Hansen and his colleagues released a statistical analysis this summer suggesting that the odds are too great for many of the past decade's most extreme weather events to have happened by chance. He wrote in the Washington Post, "our analysis shows that, for the extreme hot weather of the recent past, there is virtually no explanation other than climate change."

McKibben also challenged two of Maher's panelists, Will Cain, a contributor to Glenn Beck's TheBlaze, and former Republican Congressman Mark Foley. Although Cain didn't deny anthropogenic climate change, and begins by saying "Bill, if I grant you all your premises," he cautioned against mitigation efforts that would make the "cure worse than the disease."

A recent report, commissioned by 20 world governments and produced by the humanitarian organization DARA, found that the effects of climate change could cost the global economy 3.2 percent of potential output by 2030, while the world's poorest nations could see an "11 percent loss in GDP by 2030 due to climate change," reported Reuters. Yet economists have suggested that an "investment equivalent to 2 percent of global GDP [is] needed to limit, prevent and adapt to climate change."

In response to Cain's suggestion that humans have adapted to their environments in the past and will in the future, McKibben scoffed, "What are we going to develop that replaces Iowa?"

Foley told McKibben, "I'm not suggesting I disagree with you," but asked for an explanation as to why it was hotter in Chicago than Florida this summer.

McKibben responded, "That's why we look around the world and observe that every month for the last 330 it's been warmer than it was in the last century." He tells Foley that comparing a single day's weather in two places doesn't "even begin to be an argument."

Watch a one minute clip from the segment above. HBO subscribers can watch the entire interview here.

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  • On Record Sea Ice Loss

  • On Why Arctic Ice Melt Is Bad

  • On Adapting To Climate Change

  • On The Scientific Consensus Of Climate Change

  • On The Limitations Of Climate Change Adaptation

  • On The Power Of The Fossil Fuel Industry

  • On Predictions Of Decreased Crop Yields Under 4-5º Of Warming

  • On The Importance Of Movements

  • On Sen. Inhofe (R-OK) And Congressional Climate Deniers

  • Responding To Mark Foley's Weather Comments