GlobalChange.gov has a helpful resource page for educators, although it is useful for anyone who wants to learn more about global change. In particular, their 18 page (really only about 9 pages of text given the pictures) climate literacy guide will be valuable in helping educators understand key climate ideas so they are comfortable incorporating climate assignment into the classroom.
Climate Literacy: The Essential Principles of Climate Science is an interagency guide that provides a framework and essential principles for formal and informal education about climate change. It presents important information for individuals and communities to understand Earth’s climate, impacts of climate change, and approaches for adapting and mitigating change. Principles in the guide can serve as discussion starters or launching points for scientific inquiry. The guide can also serve educators who teach climate science as part of their science curricula.
The page contains links to other resources such as an energy literacy guide, a wildlife and wetlands toolkit, and climate change educational videos.