There's an amusing pair of headlines back-to-back today on what a Greek exit from the Eurozone might mean.

 One view is catastrophic, the other is along the lines of no problem. Let's start with the catastrophe.

Economic historian Barry Eichengreen says Greek Euro Exit Would be 'Lehman Brothers Squared.

A decision by a new Greek government to leave the eurozone would set off devastating turmoil in financial markets even worse than the collapse of Lehman Brothers in 2008, a leading international economist warned Saturday.

A Greek exit would likely spark runs on Greek banks and the country's stock market and end with the imposition of severe capital controls, said , an economic historian at the University of California at Berkeley. He spoke as part of a panel discussion on the euro crisis at the American Economic Association's annual meeting.

The exit would also spill into other countries as investors speculate about which might be next to leave the currency union, he said.