The bond market is sending a warning on growing US debt, Ed Yardeni said.
• That's seen in rising bond yields, with the yield on the 10-year Treasury surpassing 4%.
• Yields could touch 4.5% this year and spark a sell-off in stocks, Yardeni warned.
The bond market is flashing a warning about America's debt problem, and stocks could be confronted with a sell-off as yields on…