At an estimated 10.3 percent of gross domestic product (GDP), the deficit in 2021would be the second largest since 1945, exceeded only by the 14.9 percent shortfall recorded last year. ... By the end of 2021, federal debt held by the public is projected to equal 102 percent of GDP. Debt would reach 107 percent of GDP (surpassing its historical high) in 2031 and would almost double to 202 percent of GDP by 2051. Debt that is high and rising as a percentage of GDP boosts federal and private borrowing costs, slows the growth of economic output, and increases interest payments abroad. A growing debt burden could increase the risk of a fiscal crisis and higher inflation as well as undermine confidence in the U.S. dollar, making it more costly to finance public and private activity in international markets.Here are a few illustrative figures. The first one shows accumulated federal debt over time since 1900. You see the bumps for debt accumulated during World Wars I and II, and during the Great Depression of the 1930s. If you look at the 1980s, you can see the Reagan-era rise in debt/GDP. But after the debt/GDP ratio had sagged back to 26.5% by 2001, you can see the the big jump for debt incurred during the Great Recession, and then debt incurred during the pandemic recession, and then where the projections under current law would take us.
Larger deficits in the last few years of the decade result from increases in spending that outpace increases in revenues. In particular:
- Mandatory spending increases as a percentage of GDP. Those increases stem both from the aging of the population, which causes the number of participants in Social Security and Medicare to grow faster than the overall population, and from growth in federal health care costs per beneficiary that exceeds the growth in GDP per capita.
- Net spending for interest as a percentage of GDP is projected to increase over the remainder of the decade as interest rates rise and federal debt remains high.
Moreover, the effects on economic outcomes would depend on the types of policies that generate the higher deficits and debt. For example, increased high-quality and effective federal investment would boost private-sector productivity and output (though it would only partially mitigate the adverse consequences of greater borrowing). However, in CBO’s projections, the increasing deficits and debt result primarily from increases in noninvestment spending. Notably, net outlays for interest are a significant component of the increase in spending over the next 30 years. In addition, federal spending for Social Security, Medicare, and Medicaid for people age 65 or older would account for about halfof all federal noninterest spending by 2051, rising from about one-third in 2021.