In September and October 2008, a research team from Yale and George Mason Universities conducted a nationally representative survey of 2,164 American adults. The survey found that concerns about the economy dwarfed all other issues with global warming ranked 10th out of 11 national issues. Many Americans said that the United States should act to reduce global warming and reduce its emissions of greenhouse gases, even if it has economic costs, regardless of what other countries do. The American opinion on global warming is growing clearer with a majority now believing that it is real, happening, human-caused, and a serious threat. Similarly, many want their elected officials at all levels to take more action and support a variety of policies to reduce national greenhouse gas emissions.