View of the bed of Jacarei river dam, in Piracaia, during a drought affecting Sao Paulo state, Brazil on November 19, 2014. The Jacarei river dam is part of the Sao Paulo's Cantareira system of dams, which supplies water to 45% of the metropolitan region of Sao Paulo --20 million people-- and is now at historic low. AFP PHOTO / NELSON ALMEIDA        (Photo credit should read NELSON ALMEIDA/AFP/Getty Images)
Where does '97% consensus' on climate change come from?
CNN meteorologist Chad Myers answers a viewer question as to where the 97% consensus comes from when talking about man's impact on climate change.
02:55 - Source: CNN
2 degrees 12 videos
View of the bed of Jacarei river dam, in Piracaia, during a drought affecting Sao Paulo state, Brazil on November 19, 2014. The Jacarei river dam is part of the Sao Paulo's Cantareira system of dams, which supplies water to 45% of the metropolitan region of Sao Paulo --20 million people-- and is now at historic low. AFP PHOTO / NELSON ALMEIDA        (Photo credit should read NELSON ALMEIDA/AFP/Getty Images)
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This photo taken on March 3, 2014 shows a resident surrounded by the on-rushing high tide energized by a storm surge that damaged a number of homes across Majuro.   It was the third inundation of the Marshall's capital atoll in the past 12 months. The Marshall Islands has put climate change at the top of its political and diplomatic agenda and officials saw the recently held Cartagena Dialogue as an opportunity to gather momentum.      AFP PHOTO / Karl Fellenius        (Photo credit should read Karl Fellenius/AFP/Getty Images)
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