Carbon tax doesn't solve. International alt causes and untraceable carbon consumption.

But political feasibility in the US is not even the main problem with the carbon tax. The bigger issue: Greenhouse gas emissions are a global problem that cannot be solved by curbing polluting activities only in the United States. In 2019, the latest pre-pandemic year, the US  accounted for only about 11 percent of global greenhouse gas emissions, far below China’s  27 percent. Even if the US cut its emissions in half, world emissions would only fall by about 5 percent – a decline that would be more than offset by continued growth in emerging economies.

Carbon taxes also are porous. Producers and consumers can avoid the tax by importing foreign goods with a high carbon content. And lower prices from reduced US carbon consumption could encourage more carbon consumption in other countries.

Border taxes and selective exemptions can minimize these leakages and limit harm to US producers from competition by untaxed producers in other countries. But the issue isn’t only the leakage from the carbon tax itself; it is the amount of global emissions that simply remain outside the range of the tax. And a unilateral tax imposed by the US cannot reduce those foreign emissions.