Policymakers face complex cost-benefit considerations when intervening in the market to mitigate perceived risks, from climate change to competition with China.

The sprawling U.S. water system is central to the nation’s economy, but chronic underinvestment, increasing demand, and the consequences of climate change have revealed the system’s weaknesses.  

See how six countries are faring amid efforts to protect 30 percent of the planet’s land and waters by 2030, and what will be saved if they succeed. 

Conceived as the principal defenders of the 1979 revolution, the Islamic Revolutionary Guard Corps has evolved into an institution with vast political, economic, and military power.