It has been dubbed the “wall of debt.”

A massive wave of borrowing will start cresting this year when the U.S. and European governments sell an estimated $4 trillion in new bonds. The surge will course through the world financial system for several years as countries, corporations and banks borrow record amounts of money to repair the damage from the financial crisis and pay back loans from the boom that preceded it.

One crucial concern about the nascent economic recovery is whether that new debt can be smoothly absorbed by markets or instead will force less creditworthy governments into a Greek-style crisis, push weaker banks and corporations into default and possibly trigger another downturn.

Analysts are split on the prospects. Large amounts of cash around the world and the expectation of continued low interest rates argue for a trouble-free outcome, while the sheer level of debt involved has others spooked about a destructive competition for credit.

The steep amount of debt has become a source of concern among economists at the International Monetary Fund and others who are trying to anticipate where the next crisis might arise.

“There will be a tightening of financial conditions,” said Mohammed El-Erian, chief executive at bond fund PIMCO, who said the company expects that governments, corporations and leveraged buyout firms will all have to cope with stiffer requirements as they refinance maturing bonds, “some of which will not be refinanced on any terms.”

In a series of recent reports, the IMF questioned the ability of governments and banks to raise the money they need as they collide in the markets with multitrillion-dollar tabs – a dynamic of basic supply and demand that could raise interest rates as those selling bonds bid up the rate they are willing to offer investors.

That potential for high levels of government borrowing to raise rates or even displace corporate bond sales – depriving companies of an important source of financing – is a key reason the agency wants governments to trim deficits.

Greece’s large refinancing needs this year sparked its recent crisis and threatened a larger and potentially global financial seizure when the country appeared at risk of default.

Although the European Union and the IMF have set up a fund to guard against a recurrence of that sort of problem, the actual mechanism has not been tested, and the IMF noted that interest rates had begun rising again for Spanish, Italian and some other European government debt.