Short answer: In most advanced, aging economies, an abrupt stop to immigration would make labor shortages more likely—especially in certain occupations and places—though the size and persistence of those shortages would depend on how markets and policies respond.
Why immigration matters for labor supply
•Demographics: Many countries have below‑replacement fertility and aging workforces. Without new workers arriving, the working‑age population grows more slowly or shrinks, raising vacancy rates and wage pressure in tight sectors.
•Occupation mix: Immigrants are overrepresented in some hard‑to‑fill roles (e.g., agriculture, eldercare, hospitality, construction, some STEM and healthcare jobs). Halting inflows hits these bottlenecks first.
•Geography: Newcomers often move to fast‑growing metros and regions where local labor pools are thin, easing local mismatches.
•Complementarity: Immigrant workers can complement natives (freeing up higher‑skill roles or enabling longer business hours). Removing complements can reduce overall productivity and job creation.
How the economy would adjust (and why shortages can still persist)
•Wages and conditions rise to attract locals, but that raises prices; in some jobs the pool of willing and able local workers is limited even with higher pay (physically taxing, seasonal, off‑hours, rural).
•Firms substitute: automate, change business models, offshore, or scale back. These take time and capital, and some tasks (hands‑on care) automate poorly.
•Training/upskilling helps, but pipelines for nurses, electricians, or software engineers are multi‑year, so near‑term gaps remain.
•Participation can increase (e.g., older workers, caregivers), but gains are typically modest without broader policy changes.
Net effect by time horizon
•Short run (1–3 years): More unfilled vacancies in immigrant‑reliant sectors and regions; faster wage growth there; some service cutbacks or delays.
•Medium to long run (3–10+ years): Slower labor‑force growth, tighter care and trades markets, higher dependency ratios, and potentially slower GDP growth—unless offset by strong productivity and participation gains.
What could offset a stop to immigration
•Raise participation: child‑care support, flexible schedules, disability and re‑entry reforms, later retirement incentives.
•Speed training: apprenticeships, fast‑track licensing, community‑college partnerships tied to employer demand.
•Improve job quality: safety, predictable shifts, housing/transport in remote worksites.
•Invest in productivity: automation, process redesign, and capital deepening.
•Family policy to lift fertility—effective but slow to change workforce numbers.
Bottom line: Completely stopping immigration would not guarantee economy‑wide shortages everywhere, but it would materially increase the risk and severity of shortages in specific sectors and places, especially in countries with aging populations and already tight labor markets. Targeted immigration alongside the offsets above is generally a faster and cheaper way to relieve bottlenecks than relying on domestic adjustments alone.
If you can share the country/region, sectors you care about, and your time horizon, I can give a sharper, numbers‑based forecast.