This story originally appeared on Bulletin of the Atomic Scientists and is part of the Climate Desk collaboration.

When I pull into a parking lot in my Toyota 4Runner, I hope I won’t see any of my friends who are environmental activists. I hope I’ll fit into the eco-conscious (read small) parking spaces at some of the places I shop. I feel like a skinny-car person in a fat-truck body.

It turns out that vehicles like mine—known as sport utility vehicles, or SUVs—are even worse for the climate than I had imagined. And I imagined they were pretty bad.

A massive carbon footprint

According to a summary analysis of a report by the International Energy Agency that was released on November 13, SUVs are the second-biggest cause of the rise in global carbon dioxide emissions during the past decade. Only the power sector is a bigger contributor.

The analysis, which surprised even its own authors, found a dramatic shift toward SUVs. In 2010, one in five vehicles sold was an SUV; today it’s two in five. “As a result, there are now over 200 million SUVs around the world, up from about 35 million in 2010,” the agency reports.

The preference for heavier SUVs is offsetting fuel-efficiency improvements in smaller cars and carbon savings from the growing popularity of electric cars. “If SUV drivers were a nation, they would rank seventh in the world for carbon emissions,” reported The Guardian.

I’m part of that imaginary nation. I don’t have kids. I don’t fly often. But I have a big honkin’ SUV that is killing the planet. For those of us who are worried about our carbon footprints, driving an SUV is like wearing a pair of size-18 steel-toe boots.

Status symbols on wheels

What’s the attraction of SUVs? Consumers who buy them hand manufacturers a higher profit margin than for smaller vehicles. The weight and boxy shape of SUVs makes them less fuel-efficient, so they cost more to operate and are less nimble than passenger cars. Some people feel safer in a vehicle where they sit high above the road, but the raised center of gravity makes SUVs more prone to rollovers than cars, said Consumer Reports. Some people want an SUV because they believe that an all-wheel-drive or four-wheel-drive option will make them safer in bad weather. In reality, many drivers do not need this expensive and fuel-economy-lowering feature, and would be better off with front-wheel-drive and good tires.

Still, those disadvantages didn’t stop me and my husband from buying a full-size SUV that weighs 4,675 pounds and averages only about 19 miles per gallon. We claim we “need” an SUV to get around in the rural, mountainous area where we live, but somehow we managed to survive here for a decade without one.

People often buy vehicles for reasons that have very little to do with functionality. For many people, an SUV is a status symbol. And that is also true—perhaps even more so—for people who drive hybrid or all-electric passenger cars. A 2007 survey of Toyota Prius buyers found that more than half said they purchased a Prius because “it makes a statement about me.” Some of them are now incensed that Toyota is siding with the Trump administration against California’s efforts to improve fuel economy.

I have the opposite problem. I appreciate the utility of my sport utility vehicle, but I’m embarrassed to be seen in it. Call it “SUVskam,” Swedish for SUV shame. I’m not so ashamed (or wealthy) that I will drive to the nearest junkyard and have it crushed for its scrap metal. But I am doing everything I can to reduce the carbon footprint of my SUV.

What would Greta drive?

SUVskam isn’t a thing yet, but flight shame (or “flygskam” in Swedish) is, thanks in part to the efforts of Swedish teenage climate activist Greta Thunberg to raise public awareness of the carbon emissions associated with air travel. In Europe, many flight-shamed people are switching from planes to trains. Thunberg went a step further, avoiding flygskam by taking a sailboat instead of an airliner when she traveled to the United States—and again when she left for Spain last week. Flight shame has reduced air travel enough to catch the attention of the International Air Transport Association, which is launching a campaign to tout its environmental efforts.