The researchers concluded that taxing luxury goods and services such as air travel and SUVs would be a fairer and more effective way to reduce household carbon emissions than applying a flat carbon tax to all purchases. Carbon taxes are fees applied to goods and services according to the carbon footprint associated with their production or delivery. They are designed to increase income and reduce the consumption of polluting products. Such taxes apply around the world, but carbon is usually taxed at a flat rate regardless of the product it is associated with. Some economists argue that this is an unfair and largely ineffective system for dealing with household emissions, especially in higher-income countries. This is because some high-carbon expenses, such as heat and fuel, are essential for many households, so carbon taxes will do little to change spending patterns. Meanwhile, lower-income households—who spend a greater proportion of their income on basic goods and services—are hit harder by higher prices. (Madeleine Cuff, news scientist)