Objective. We examine cognitive, economic, and partisan heuristic theories of why some people express support for reducing greenhouse gas emissions. Methods. Data come from a mail survey of 623 residents of central Pennsylvania, a region in which mitigation costs exceed potential benefits from slowing the rate of global warming. Results. Ordinary least squares analysis shows that people who can accurately identify the causes of climate change and who expect bad consequences from climate change are likely to support both government anti‐fossil fuel initiatives and voluntary actions. Economic circumstances and anxieties are not important predictors, but the belief that environmental protection efforts do not threaten jobs for people like the respondent, limit personal freedoms, and hurt the economy is a strong predictor. Democrats are more likely than Republicans to support government efforts to reduce emissions. Conclusions. Cognitive explanations of support for reducing greenhouse gas emissions are more powerful than economic or partisan heuristic ones. People want to reduce emissions if they understand the causes of climate change, if they perceive substantial risks from climate change if average surface temperatures increase, and if they think climate change mitigation policies will not cost them their jobs.