In 2021, the research firm Ipsos asked 21,000 people in 30 countries to choose from a list of nine actions they thought would most reduce greenhouse gas emissions for individuals living in a wealthier country. Most people chose recycling, followed by buying renewable energy, switching to an electric/hybrid car, and choosing low-energy light bulbs. When these actions were ranked by their actual impact on emissions, recycling was third from last, and low-energy light bulbs were last. None of the top three options people chose appeared in the “real” top three in terms of greenhouse gas emissions reduction, which include having one less child, not owning a car, and avoiding one long-haul flight. It’s not that people are stupid; it’s that the most effective options don’t always intuitively make sense to us. The survey also asked people what they thought about the impact of different types of diets on the climate. Respondents were asked which diet had the lowest greenhouse gas emissions: a vegetarian diet with some imported products or a locally produced diet that includes meat and dairy products. About 57 percent of people thought that a locally produced diet had the lowest impact, with only 20 percent choosing a vegetarian diet and 23 percent opting for “don’t know.” (MATT REYNOLDS)