Climate policy or climate change policy is policy about climate change. It is often decided by national governments - for example the climate policy of China. It may include policy on reducing greenhouse gas emissions to limit climate change, and also adapting to climate change. Or not. National climate policy sometimes conflicts with sub-national or bloc policy, for example the climate change policy of Washington (state) diverges from the climate change policy of the United States, and EU climate policy can conflict with other national policies. Climate policies may have very big co-benefits for health policy such as by: reducing air pollution, increasing walking and cycling, and eating less beef; they may also help energy policy by reducing oil imports. Public support for policies depends on: how effective people think they are in reducing emissions, their impact on poor people, their effect on respondents’ households, and how well they understand them. Climate-economy modelling may help when deciding policy. Policy, such as target dates for net-zero emissions, may be put into law. Tax is usually a good policy.