The world’s mightiest, and arguable dirtiest, private sector fossil fuel producer, and perhaps its most famous entrepreneur to stake his considerable fortune on a future of low greenhouse emissions, agree on one thing: we need to tax carbon.

Bloomberg Business draws attention to the alignment of views between ExxonMobil Corp. and Elon Musk in a piece that also lays out a strong case for putting a broadly based tax on carbon emissions—essentially creating a price penalty for Exxon’s product that makes renewable energy—whose interruptible nature Musk’s products leverage—look more economical by comparison.

A score of regional jurisdictions and twice that many countries already have some form of carbon price, the news service reports, whether a tax or a cap-and-trade system—a less-direct method of putting a cost on greenhouse emissions. Almost a quarter of global emission are subject to one form or the other of pricing.

Bloomberg explains its own preference, along with the multinational and the tycoon, for a clear tax, by describing that mechanism as “elegant in its simplicity: minimize harmful forms of consumption by making them more expensive. Most countries already follow this strategy for products like alcohol and tobacco.”

The other good reason for a carbon tax, it offers: “It works.”