Bachmann rejects the overwhelming scientific consensus that climate change is real, progressing, and primarily caused by humans. She has claimed that global warming is "all voodoo, nonsense, hokum, a hoax" and has been called "one of the GOP's loudest global warming skeptics." She has claimed, baselessly, that "because life requires carbon dioxide and it is part of the planet's life cycle, it cannot be harmful." On the House floor on Earth Day 2009, Bachmann said she opposed cap and trade climate legislation, again making disproven claims that "carbon dioxide is not a harmful gas, it is a harmless gas. Carbon dioxide is natural; it is not harmful ... We're being told we have to reduce this natural substance to create an arbitrary reduction in something that is naturally occurring in the earth."