Greenpeace co-founder, Dr. Patrick Moore:
“There is no definitive scientific proof… that carbon dioxide is responsible for any of the slight warming of the global climate that has occurred during the last 300 years.”
“But there is certainty beyond a reasonable doubt that CO2 is the building block for all life on Earth, and that without its presence in the global atmosphere… this would be a dead planet.”
Full talk: https://www.youtube.com/watch?v=d0Z5FdwWw_c