Costa Rica, known for its white-sand beaches and cloud-draped forests, is a meager contributor to global climate change. Its largest provider of electricity, which relies almost entirely on hydropower, can go months without burning any fossil fuels. Yet, despite its miniscule role in warming the climate, this Central American country is among the nations trying hardest to curb greenhouse gases.

An ocean away, Australia is another story. This coal-rich nation spews more CO2 per capita than almost every other country, putting it nearly on par with the United States. But Australia lacks Costa Rica's ambition, and its carbon-cutting goal is less aggressive than the U.S. government’s.

The tale of these two countries half a world apart highlights an often-overlooked reality: