The National Association of Biology Teachers recently released a revised version of its position statement (PDF) on teaching about climate change.
Describing the teaching of global climate change as "necessary for a comprehensive understanding of the natural world," the statement emphasizes that the "facts and implications of climate change as presented in science classes are not scientifically controversial," but are supported by "[t]he overwhelming preponderance of peer-reviewed studies and the vast majority of climate scientists."
The statement recommends that educators "teach global climate change in an effective, detailed, and scientifically- and pedagogically-honest manner and work to encourage the development of and support for standards, curricula, textbooks, and other instructional frameworks that prominently include global climate change and reflect current consensus understanding of its mechanisms."
A collection of statements from scientific and educational organizations expressing their support for teaching climate change is available on NCSE's website.