Any critically-thinking parent whose child has been forced to watch Al Gore’s An Inconvenient Truth will sympathize with petitions to ban discussions of global warming in public school science classes. Apparently such petitions are starting to crop up around the US. But I think this impulse, while understandable, is deeply misguided, as Vincent Carroll argues in the Denver Post.
While it might be easier just to avoid subjects like man-made global warming (or Darwinian evolution), it’s hard to see how scientific literacy will be improved by avoiding them altogether. It’s much better to separate the data from the propaganda (a tall task, to be sure) and to help students learn to analyze the issue. As Carroll argues:

Climate change happens to be an important scientific issue, and it would be foolish to ban its discussion simply because some teachers are too unsophisticated — or too ideological — to distinguish between propaganda and an appropriate lesson plan. In fact, climate change is a model topic for teaching students the complexities and uncertainties that characterize evolving scientific theories, while introducing them to a range of opinion among scholars — from MIT’s Richard S. Lindzen to NASA’s James Hansen — as well as the “consensus” view represented by the scandal-plagued Intergovernmental Panel on Climate Change.
Students could examine a phenomenon often linked to warming, such as natural disasters. Have they become more common and more deadly? Is there a debate about it? Why? And just how do scientists reconstruct surface temperatures from long ago? Are some of their methods controversial?
A global warming unit would also provide an opportunity to point out that science itself does not dictate the appropriate policy response, whatever activists (and some scientists) insist. Students could be asked to identify the best arguments for taking dramatic steps to reduce consumption of fossil fuels as well as the counter-arguments — that such steps won’t achieve their goals, for example, and would meanwhile slow economic growth and thus cripple the world’s ability to adapt to whatever warming eventually occurs.

Exactly right. In fact, I suspect that if schools could implement such an approach with controversial issues, the desire to ban their teaching would disappear.