There’s a simple logic behind most government budgets: keep energy and food cheap, keep people working. In practice, this often means helping the people who grow the world’s food and fiber.

Every year, governments spend public money on fishing, farming and forestry — encouraging farmers to use more fertilizer, lowering the cost of raising cattle, and helping fishers increase their catch.

Those payments, called subsidies, often end up damaging nature. It happens largely by accident. For example, when all that cheap and over-applied fertilizer runs off into nearby rivers. When ranching pushes into forests. When fishing fleets begin to take more than the ocean can handle.

In a new report , Conservation International found US$ 2.1–2.7 trillion in government subsidy spending each year that drives deforestation, overfishing and pollution. The price tag only mounts from there.…