A Changing Nation: Population Projections Under ...

A Changing Nation: Population Projections

Under Alternative Immigration Scenarios

Population Estimates and Projections

Current Population Reports

By Sandra Johnson

P25-1146

Issued February 2020

INTRODUCTION

Higher international immigration over the next four

decades would produce a faster growing, more

diverse, and younger population for the United States.

In contrast, an absence of migration into the country

over this same period would result in a U.S. population that is smaller than the present. Different levels of

immigration between now and 2060 could change the

projection of the population in that year by as much

as 127 million people, with estimates ranging anywhere from 320 to 447 million U.S. residents.

Beyond influencing the number of people in the

population, immigration patterns over the next four

decades will also shape the racial and ethnic composition of the population. In 2016, Asians were the

fastest-growing racial group in the nation, and immigration was the primary driver behind the growth in

this group. If immigration increases, the Asian alone

population could grow by as much as 162 percent

between 2016 and 2060 and go from 5.7 percent of

the total U.S. population to 10.8 percent. The future

size of this population is particularly sensitive to

immigration. Under a scenario with no immigration,

the Asian alone population in the United States would

decline over time, representing just 4.5 percent of the

total population in 2060.

Regardless of immigration, the population is expected

to continue to age between now and 2060. Low fertility rates coupled with large cohorts of baby boomers

reaching their ¡°golden years¡± are expected to shift the

age distribution of the population so that the share of

the population aged 65 and older exceeds the share

of the population under the age of 18. The timing of

this shift, however, will vary depending on the amount

of immigration that occurs. High immigration levels

will delay this milestone more than a decade relative

to scenarios with lower levels of migration.

The 2017 National Projections main series, released in

September 2018, present one scenario for the future

population.1 These projections will only hold true if

the assumptions about births, deaths, and migration match the actual trends in these components of

population change. International migration is difficult

to project because political and economic conditions

are nearly impossible to anticipate, yet factor heavily

into migration movements into and out of a country.

While we do not attempt to predict future policy or

economic cycles, we do recognize the uncertainty

surrounding migration and the impact that different

migration outcomes could have on the future population. To account for this, we have produced three

alternate sets of projections that use the same methodology and assumptions for fertility, mortality, and

emigration, but differ in the levels of immigration that

they assume: high, low, and zero immigration. This

report compares the results from the three alternative

scenarios of projections and the main series, focusing

on differences in the pace at which the U.S. population grows, diversifies, and ages.

1

The 2017 National Projections were initially released in

December 2017, but were retracted when an error was identified in

the mortality rates. A revised version was released in September

2018.

2017 NATIONAL POPULATION PROJECTIONS ALTERNATIVE SCENARIOS

The results in this report are based on the 2017

National Population Projections, which are the

third set of projections based on the 2010 Census,

and cover the period from 2017 to 2060. The 2017

National Population Projections include projections of the resident population by age, sex, race,

Hispanic origin, and nativity (whether people were

born in the United States or another country). They

are based on official population estimates through

2016. This series uses the cohort-component

method, which projects the three components of

population change¡ªfertility, mortality, and international migration¡ªseparately for each birth cohort

based on historical trends. The base population

is advanced each year using projected survival

rates and net international migration. New birth

cohorts are added to the population by applying

the annual projected fertility rates to the female

population.

The main series of projections, released in

September 2018, assumes that future international

migration will mirror recent historical trends; this

is the ¡°middle¡± migration assumption. In addition to the main series, we also produced three

alternative scenarios that are ¡°what if¡± exercises,

examining how the U.S. population would change

if future patterns of immigration differ radically

from historical trends. For each of the three scenarios described below, the fertility, mortality, and

HIGHLIGHTS FROM THE 2017

NATIONAL POPULATION

PROJECTIONS

Population Growth

?? Over the next four decades,

the population is expected to

increase from its 2016 level in

2

emigration assumptions are the same as those

used in the main series; the only component that

differs is immigration.

Zero immigration scenario. Assumes that immigration into the United States falls to zero (the

theoretical minimum). Under this scenario, there

is no immigration, but we still allow for emigration

out of the United States. This offers the most dramatic picture of demographic change.

High immigration scenario. Assumes immigration

increases by 50.0 percent compared with levels

from 2011 to 2015 for all projected years. This scenario shows what the outcome would be if we were

underestimating immigration by half in the main

series.

Low immigration scenario. Assumes that immigration rates are roughly cut in half from their 2011

to 2015 levels. This scenario is not strictly 50.0

percent less, but is log symmetrical to the values

for the high migration scenario. As a result, the

projected migration rates vary between 40 and

50 percent less than those projected for the main

series in any of the given years, starting with 2017.

For more information on the data and methodology, see the report on the 2017 National Population

Projections: Methodology and Assumptions

.

two out of the three alternative

scenarios. In the high scenario,

the population will increase by

124 million, reaching 447 million

in 2060. In the low scenario, the

2060 population is projected to

be 376 million, representing an

increase of 53 million people.

?? Under a zero immigration scenario, the population is projected to increase until 2035,

at which point the population

would peak at 333 million. After

that, the population is projected to decline through 2060,

when it could reach a low of

320 million.

U.S. Census Bureau

?? In the main series of projections, the population is projected to reach the 400 million

milestone in 2058. This threshold is crossed 15 years earlier

in the high scenario and is not

attained in either the low or

zero immigration scenario.

?? The average annual growth in

the population is 2.8 million

people in the high scenario,

compared to 1.8 million in the

main series, 1.2 million in the

low, and ¨C78 thousand in the

zero immigration scenario.

Population Diversity

?? The share of the population

that is White alone is projected

to decline in all scenarios of

population projections between

2016 and 2060. For the high,

middle, and low scenarios,

the number of residents classified as White alone actually

increases from the 2016 values,

but these increases are outpaced by increases in the other

racial and ethnic groups.

?? The non-Hispanic White alone

population is projected to

decline in all scenarios between

2016 and 2060. In 2016, there

were an estimated 198 million

individuals in this group. In the

high scenario, this number is

projected to decrease by 11 million in 2060 to 187 million. The

U.S. Census Bureau

2060 projection for this group

in the low scenario is 174 million, a decrease of 24 million;

and in the zero scenario, it is 163

million. The non-Hispanic White

alone population is projected

to decrease the most between

2016 and 2060 in the zero immigration scenario (35 million).

?? The Two or More Races group is

the fastest-growing racial group

between 2016 and 2060 in all

projection scenarios. In 2016,

just under 8.5 million residents

were classified as more than

one race. This number is projected to more than double for

all scenarios. The zero immigration scenario, with a projected

160 percent increase, has the

smallest Two or More Races

population in 2060 (22 million).

In contrast, the high immigration scenario has the largest

increase (216 percent or 18

million) and the largest Two or

More Races population in 2060

(27 million).

?? Projected changes in the

foreign-born population

between 2016 and 2060 vary

across the scenarios and are

consistent with the immigration assumptions used. In the

high immigration scenario, the

percentage of the population

that is foreign-born is projected

to increase from 13.6 percent

to 21.6 percent. In the low, it

remains relatively stable at

just under 14 percent through

2060; and in the zero immigration scenario, it decreases to a

historic low of 4.6 percent.

Population Aging

? The population aged 65 and

older is projected to surpass

the population under the age

of 18 in size in all immigration

scenarios. The date at which

this occurs is earliest in the zero

immigration scenario (2029),

followed by the low immigration scenario (2031), and then

the high (2045).

? By 2030, more than 20 percent of the U.S. population will

be aged 65 and older. In the

high scenario, this milestone is

reached in 2028. For the low

scenario, it occurs in 2026; and

in 2025 for the zero scenario.

? The number of children (ages

0¨C17) is projected to decline in

both the low and zero immigration scenarios. In 2016, there

were an estimated 74 million

children in the population.

By 2060, this is projected to

decline to 59 million in the zero

scenario and to 73 million in the

low scenario. Conversely, the

child population is projected to

increase to just under 91 million

by 2060 in the high scenario.

3

POPULATION GROWTH

The projected change in the population depends on what assumptions are made about the fertility,

mortality, and migration behaviors

of that population in the future.

Changing the assumptions about

any one of these components will

alter the projected size and composition of the population over

time. For the alternative population projections, we have developed three scenarios where we

increase, decrease, and eliminate

immigration. These complementary projections provide information on how different immigration

trends could shape the U.S. population through 2060.

Comparing population growth

over time from all of the scenarios

reveals patterns that are consistent with the different immigration assumptions used (Table 1

and Figure 1). Higher immigration produces more population

growth relative to the main series

of projections, and lower immigration produces diminished growth.

In the main series of population

projections, the U.S. population

is projected to increase by 25

percent between 2016 and 2060,

from 323 million to 404 million. In

a higher immigration scenario, the

2060 population is projected to

grow to 447 million, an increase

of 38 percent over the 2016 value.

Table 1.

Projected U.S. Population by Immigration Scenario:

2016 to 2060

(Numbers in thousands)

Year

Alternative immigration scenario

Main series

Low

High

Zero

Numeric change:

2016 to 2060. . . . . . . . . .

81,356

53,099

123,738

¨C3,422

Percent change:

2016 to 2060. . . . . . . . . .

25.18

16.43

38.29

¨C1.06

2016. . . . . . . . . . . . . . . . . . .

2017. . . . . . . . . . . . . . . . . . .

2018. . . . . . . . . . . . . . . . . . .

2019. . . . . . . . . . . . . . . . . . .

2020. . . . . . . . . . . . . . . . . . .

2021. . . . . . . . . . . . . . . . . . .

2022. . . . . . . . . . . . . . . . . . .

2023. . . . . . . . . . . . . . . . . . .

2024. . . . . . . . . . . . . . . . . . .

2025. . . . . . . . . . . . . . . . . . .

2026. . . . . . . . . . . . . . . . . . .

2027. . . . . . . . . . . . . . . . . . .

2028. . . . . . . . . . . . . . . . . . .

2029. . . . . . . . . . . . . . . . . . .

2030. . . . . . . . . . . . . . . . . . .

2031. . . . . . . . . . . . . . . . . . .

2032. . . . . . . . . . . . . . . . . . .

2033. . . . . . . . . . . . . . . . . . .

2034. . . . . . . . . . . . . . . . . . .

2035. . . . . . . . . . . . . . . . . . .

2036. . . . . . . . . . . . . . . . . . .

2037. . . . . . . . . . . . . . . . . . .

2038. . . . . . . . . . . . . . . . . . .

2039. . . . . . . . . . . . . . . . . . .

2040. . . . . . . . . . . . . . . . . . .

2041. . . . . . . . . . . . . . . . . . .

2042. . . . . . . . . . . . . . . . . . .

2043. . . . . . . . . . . . . . . . . . .

2044. . . . . . . . . . . . . . . . . . .

2045. . . . . . . . . . . . . . . . . . .

2046. . . . . . . . . . . . . . . . . . .

2047. . . . . . . . . . . . . . . . . . .

2048. . . . . . . . . . . . . . . . . . .

2049. . . . . . . . . . . . . . . . . . .

2050. . . . . . . . . . . . . . . . . . .

2051. . . . . . . . . . . . . . . . . . .

2052. . . . . . . . . . . . . . . . . . .

2053. . . . . . . . . . . . . . . . . . .

2054. . . . . . . . . . . . . . . . . . .

2055. . . . . . . . . . . . . . . . . . .

2056. . . . . . . . . . . . . . . . . . .

2057. . . . . . . . . . . . . . . . . . .

2058. . . . . . . . . . . . . . . . . . .

2059. . . . . . . . . . . . . . . . . . .

2060. . . . . . . . . . . . . . . . . . .

323,128

325,511

327,892

330,269

332,639

334,998

337,342

339,665

341,963

344,234

346,481

348,695

350,872

353,008

355,101

357,147

359,147

361,099

363,003

364,862

366,676

368,448

370,179

371,871

373,528

375,152

376,746

378,314

379,861

381,390

382,907

384,415

385,918

387,419

388,922

390,431

391,947

393,473

395,009

396,557

398,118

399,691

401,277

402,874

404,483

323,128

325,024

326,909

328,782

330,640

332,477

334,289

336,071

337,820

339,532

341,213

342,849

344,439

345,979

347,467

348,901

350,281

351,607

352,881

354,104

355,277

356,404

357,485

358,524

359,522

360,484

361,411

362,308

363,178

364,026

364,856

365,672

366,477

367,274

368,068

368,862

369,657

370,455

371,258

372,068

372,884

373,708

374,540

375,380

376,226

323,128

326,243

329,366

332,499

335,638

338,781

341,921

345,056

348,179

351,287

354,384

357,464

360,521

363,552

366,552

369,517

372,445

375,335

378,186

380,999

383,775

386,514

389,219

391,892

394,536

397,154

399,748

402,324

404,885

407,437

409,984

412,529

415,078

417,635

420,202

422,783

425,381

427,998

430,634

433,290

435,966

438,663

441,379

444,114

446,866

323,128

324,048

324,943

325,809

326,641

327,434

328,183

328,884

329,533

330,128

330,675

331,157

331,573

331,920

332,198

332,408

332,549

332,624

332,636

332,587

332,478

332,314

332,096

331,827

331,510

331,146

330,739

330,293

329,810

329,295

328,752

328,183

327,592

326,983

326,358

325,720

325,072

324,416

323,753

323,084

322,412

321,737

321,061

320,384

319,706

Source: U.S. Census Bureau, 2017 National Population Projections.

4

U.S. Census Bureau

Figure 1.

U.S. Population 1900¨C2016, Population Projections 2017¨C2060 by Immigration Scenario

(In millions)

The U.S. population would shrink under a zero immigration scenario.

446.9

U.S. population

Main series

High immigration scenario

Low immigration scenario

Zero immigration scenario

323.1

U.S. population

in 2016

404.5

376.2

319.7

281.4

150.7

76.2

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 2060

Note: Census values for 1950 and earlier exclude the populations of Alaska and Hawaii.

Source: U.S. Census Bureau, 2017 National Population Projections; U.S. Census Bureau, 2016 National Population Estimates;

U.S. Census Bureau, 1900¨C2000 Decennial Censuses.

Lower levels of immigration would

reduce the growth in the population, so that by 2060 the population is projected to only increase

by 16 percent to 376 million. Under

the scenario with no immigration, the population is projected

to shrink from its 2016 value by

1.1 percent down to 320 million

people in 2060 (Figure 2).

Figure 2.

Projected Population Change Between 2016 and 2060 by

Immigration Scenario

Population change between 2016 and 2060 ranges from ¨C3.4 to 123.7

million, depending on immigration.

Projected population

change in millions

Main series

Projected

percent change

High immigration

scenario

123.7

Low immigration

scenario

Zero immigration

scenario

25.2

81.4

53.1

-3.4

38.3

16.4

-1.1

Source: U.S. Census Bureau, 2017 National Population Projections.

U.S. Census Bureau

5

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