As far as Sen. Bernie Sanders (I-Vt.) is concerned, there is no such thing as being too ambitious when it comes to dealing with climate change.

When talk turned to the Green New Deal, some of the more moderate Democratic presidential candidates, like former Rep. John Delaney of Maryland and former Colorado Gov. John Hickenlooper, were critical of the plan, calling it unrealistic. Moderator Dana Bash then asked Rep. Tim Ryan of Ohio what he thought of Sanders' idea to end new gas-powered car sales by 2040. He explained he wants to create a "chief manufacturing officer" who would work with government departments, the private sector, and investors to "dominate the electric vehicle market."

All this set off Sanders, who responded, "I get a little bit tired of Democrats afraid of big ideas. Republicans are not afraid of big ideas — they could give $1 trillion in tax breaks to billionaires and profitable corporations, they could bail out the crooks on Wall Street, so please don't tell me we cannot take on the fossil fuel industry. Nothing happens unless we do that." Sanders didn't stop there. "We've got to ask ourselves a simple question," he continued. "What do you do with an industry that knowingly, for billions of dollars in short-term profits, is destroying the planet? I say that is criminal activity that cannot be allowed."

"I didn't say we couldn't get there 'til 2040, Bernie," Ryan retorted, adding, "You don't have to yell. All I'm saying is we have to invent our way out of this thing, and if we're waiting 'til 2040 for a ban to come in on gasoline vehicles, we're screwed. So, we better get busy now." Sanders agreed that something has to be done, fast. "On this issue, there is no choice: We have got to be super aggressive if we love our children and if we want to leave them a planet that is healthy and is habitable," he said. Catherine Garcia