Carney: Shutdown a 'preview' of debt ceiling fight

"The consequences of that would be catastrophic," Carney said. 

"You know financial experts would know better than I, but you're talking about a situation where the bedrock economy in the global system, the United States economy, would suddenly be cast in doubt," he continued. "And so much of the world economy depends on the stability of the American system that default would make what's happening now under shutdown pale by comparison."

Carney also defended President Obama from charges that Democrats have proven unwilling to compromise during negotiations over a continuing resolution. Senate Democrats have repeatedly rejected Republican plans that would tie the continued funding of government to defunding or delaying the implementation of ObamaCare.

The press secretary argued it was not a concession to the White House to keep the government open, and said the president hadn't asked for anything in the shutdown showdown.

"If the president were behaving the way Republicans were, he might say, 'You know what, I won't sign a bill keeping the government open unless Republicans agree to extend background checks on gun sales' — because that's a priority of his. Or, 'I won't sign a bill to pay our bills, to prevent us from defaulting unless I get some other priority of mine that I couldn't get through the normal process,' " Carney said.