Short answer: In most advanced economies—especially ones with aging populations and low birth rates—halting immigration would likely create or worsen labor shortages, at least for several years. How big and how long the shortages last depends on wages, technology, and policy responses.
Why shortages are likely
•Demographics: With fertility below replacement, the working‑age population grows slowly or shrinks. Immigration is a key source of labor‑force growth; cutting it to zero reduces the supply of workers almost immediately.
•Sector exposure: Many industries rely heavily on immigrant labor or visas with few quick substitutes—seasonal agriculture, food processing, construction, hospitality, home health/elder care, nursing support roles, and certain high‑skill fields (e.g., software, engineering, medicine).
•Frictions that limit “just pay more”: Higher wages help, but training/credentialing takes time, many jobs are geographically mismatched with available workers, and some sectors (like farming or elder care) have tight margins—so big wage hikes can instead mean higher prices, reduced output, or closures.
•Skills and timing mismatch: You can’t rapidly produce more nurses, caregivers, or engineers; pipelines take years. Seasonal work also can’t be shifted easily to off‑season local labor.
What would happen instead
•Short run: More unfilled vacancies, longer wait times and backlogs, upward pressure on prices in services, and some output lost (e.g., unharvested crops, delayed projects).
•Medium run: Adjustment via automation, offshoring, reshaping product lines, and raising pay/benefits. Some shortages ease; some sectors shrink. Overall economic growth is likely slower, and care-intensive services stay tight because automation is harder there.
•Long run: The economy can re-equilibrate at higher wages and more capital per worker, but with a smaller workforce, a higher old‑age dependency ratio, and persistent tightness in non‑automatable, place‑bound jobs (care, many services).
When might shortages not appear?
•During a deep recession or in regions with slack, cutting inflows could have smaller immediate effects.
•If paired with strong policies that boost native labor participation (childcare, eldercare support, disability services), accelerate training and licensing reform, and encourage productivity‑enhancing tech, the impact can be muted—but not eliminated where demographics are unfavorable.
Bottom line: Stopping immigration would almost certainly tighten labor markets and create shortages in key sectors in the near term, with some adjustment over time. The economy would likely be smaller and different than it otherwise would be.
If you’re thinking about a specific country (e.g., the United States) or a particular kind of immigration (temporary visas, high‑skill, seasonal, or unauthorized), I can tailor this to that scenario and time horizon.