Evan Vucci, AP
FILE — In this Dec. 28, 2016 photo, President-elect Donald Trump listens to a question as he speaks to reporters at Mar-a-Lago, in Palm Beach, Fla.

Donald Trump promises sweeping changes in economic policies to make Americans more prosperous. However, asset and debt bubbles, enabled by easy money policies, could derail his plans and thrust the global economy into another recession.

Here are four problems that bear watching.

Housing bubble: U.S. home prices have recovered to pre-recession levels. However, in big cities where the economic recovery has been strongest, property values have soared — supercharged by rock-bottom mortgage rates and biases in Dodd-Frank regulations that push banks toward lending to the upper-middle class and wealthy.

Now the Federal Reserve, anticipating more inflation, is raising interest rates and pushing down prices would-be homeowners can afford. Similarly, overbuilding of apartments is putting stress on the rents big-city landlords can charge. As during the savings and loan crisis of the 1980s and the more recent financial meltdown, homeowners and investors may find they have overpaid, and property values in affluent urban centers may be headed for an “adjustment.”

Student debt: Outstanding student loans now exceed $1.3 trillion, and more than 40 percent of borrowers are in default or behind on payments. That debt exceeds outstanding credit card balances — and other forms of non-mortgage household debt. Eventually, the federal government will either have to make good on hundreds of billions of dollars of loans or force banks and bond investors, who purchased securitized student loans, to take big losses.

It’s another unpopular bailout in the offing or as we saw with Lehman Brothers in 2008, another opportunity for federal authorities to risk financial instability. With so many pressures on the federal budget, the Trump administration will have few pleasant choices.

European banks: European banks are suffering from slow-growing economies and ultra-low interest rates that make moving bad loans off their books and earning profits on new loans tough. About 17 percent of Italian bank loans are underwater — at the height of the financial crisis it was 5 percent for U.S. banks. The picture is troubling elsewhere on the continent, too.

Germany’s largest bank, Deutsche Bank, has been hit with a large fine by the Justice Department for its role in the financial crisis. The incident highlighted that the bank is not well run or profitable, keeps dodgy books and has wide interconnections with other banks in Europe and the United States.

Further difficulties could force it to raise new capital or resort to a “bail-in,” something European bank reforms now generally require — namely, force bondholders to accept stock for their securities and take huge losses.

This could easily ignite panic elsewhere. In Italy, ordinary depositors have been encouraged to purchase bonds in the manner that Americans invest in certificates of deposits. Bail-ins there would impose huge losses of savings and purchasing power, and a contagious recession with severe repercussions for American banks and the U.S. economy.

China: China’s national and provincial governments have subsidized inefficient state-owned enterprises and exporters with easy credit and propped up growth through excessive borrowing for wasteful public works and urbanization projects. Government deficits are estimated at 15 percent of gross domestic product, and cumulative public and private debt is 250 percent.

Printing money has pushed stocks, bonds, commodities and housing prices to threatening levels, and large investors are fleeing China, driving down the dollar value of the yuan.

Should theses bubbles burst and the yuan collapse, Asian and other developing economies dependent on exports to China could easily become unable to service their dollar-denominated debt. All this is reminiscent of the Asian currency crisis of the 1990s, which left many American lenders holding the bag.

Mr. Trump’s proposed tax, regulatory and trade reforms would accelerate U.S. growth and make emerging crises easier for U.S. banks and credit markets to absorb. For example, better job opportunities for young people would make student loans easier to repay and homes more affordable, even as interest rates rise.

Stronger U.S. growth would stimulate trade and help lift European economies and bank balance sheets. Comprehensive trade reform with China would compel Beijing to abandon export subsidies and easy credit, and finally focus on realigning its economy toward meeting pressing domestic needs.

The real challenge is that the reforms Mr. Trump advocates are not quick or easy to implement. Nevertheless, haste should be the byword, because the global economy has been propped up by easy money policies for too long.

Peter Morici is an economist and business professor at the University of Maryland, and a national columnist.