President Obama scolded "those of you who are buying gas-guzzlers" during remarks about clean energy at the North American leaders' summit in Canada on Wednesday.

Obama said he viewed the clean energy sector as an "enormous opportunity." The United States, Canada, and Mexico made a pledge to use clean energy sources to generate half of their electric power by 2025. Chuckling, Obama warned that oil was a "finite resource."

"Oil is cheap right now, but it's not going to be cheap," Obama said. "I've said this before. Those of you who are buying gas-guzzlers, I'm telling you, because it is a finite resource and it becomes more and more expensive to extract, and people are taking climate change more and more seriously … So we're in a transition phase, but in the mean time, technology is moving. And solar and wind and hydro and biomass and entire technologies we haven't even thought of yet.

"There's some 15-year-old kid somewhere who's figuring it out. I don't know whether he's in Mexico or Canada or the United States or China … Somebody out there is going to figure this out, and I want that opportunity to accrue to our workers, our people, our communities. And whoever wins this race, everybody else is going to follow."