WASHINGTON — It’s been a summer of discontent, with much of the country broiling under a heat wave like few before. Out West, parched wildlands burn. In the Midwest, farmers are sweating out another year of drought and wilted crops.

Consumers are feeling it, too, as they fume over rising food prices and muse about what’s behind the scorching temperatures. Many scientists and environmentalists, and some politicians, are sure of what’s at least partly to blame: climate change.