{"slug":"population-decline","title":"Population decline","definition":"Studies of shrinking or ageing populations, and of the housing, labour, and fiscal pressure that can follow.","connected_topics":[{"slug":"housing","title":"Housing","href":"https://greyscienx.com/topics/housing"},{"slug":"retirement","title":"Retirement","href":"https://greyscienx.com/topics/retirement"},{"slug":"inheritance","title":"Inheritance","href":"https://greyscienx.com/topics/inheritance"},{"slug":"fiscal-policy","title":"Fiscal policy","href":"https://greyscienx.com/topics/fiscal-policy"}],"study_count":9,"studies":[{"id":"GSX:POP-001","slug":"when-retirement-becomes-impossible","title":"When Retirement Becomes Impossible","primary_question":"What are the demographic and financial limits of retirement at 60?","summary":"The demographic and financial limits of retirement at 60.","research_type":"exploratory_simulation","evidence_status":"modelled","series_slug":"population-futures","series_title":"Population Futures","version":"1.0","date_modified":"2026-09-28","links":{"html":"https://greyscienx.com/research/population-futures/when-retirement-becomes-impossible","markdown":"https://greyscienx.com/research/population-futures/when-retirement-becomes-impossible/markdown","manuscript":"https://greyscienx.com/api/v1/research/when-retirement-becomes-impossible/manuscript","json":"https://greyscienx.com/api/v1/research/when-retirement-becomes-impossible","pdf":"https://greyscienx.com/research/population-futures/when-retirement-becomes-impossible.pdf"}},{"id":"GSX:POP-004","slug":"the-politics-of-an-ageing-electorate","title":"The Politics of an Ageing Electorate","primary_question":"How can voter age structure redirect spending and intergenerational transfers?","summary":"How voter age structure can redirect spending and intergenerational transfers.","research_type":"exploratory_simulation","evidence_status":"modelled","series_slug":"population-futures","series_title":"Population Futures","version":"1.0","date_modified":"2026-09-28","links":{"html":"https://greyscienx.com/research/population-futures/the-politics-of-an-ageing-electorate","markdown":"https://greyscienx.com/research/population-futures/the-politics-of-an-ageing-electorate/markdown","manuscript":"https://greyscienx.com/api/v1/research/the-politics-of-an-ageing-electorate/manuscript","json":"https://greyscienx.com/api/v1/research/the-politics-of-an-ageing-electorate","pdf":"https://greyscienx.com/research/population-futures/the-politics-of-an-ageing-electorate.pdf"}},{"id":"GSX:POP-005","slug":"emergency-ageing-austerity","title":"Emergency Ageing Austerity","primary_question":"Which policy packages for closing an ageing-related fiscal deficit are examined for lower welfare loss?","summary":"Policy packages for closing an ageing-related fiscal deficit with lower welfare loss.","research_type":"exploratory_simulation","evidence_status":"modelled","series_slug":"population-futures","series_title":"Population Futures","version":"1.0","date_modified":"2026-09-28","links":{"html":"https://greyscienx.com/research/population-futures/emergency-ageing-austerity","markdown":"https://greyscienx.com/research/population-futures/emergency-ageing-austerity/markdown","manuscript":"https://greyscienx.com/api/v1/research/emergency-ageing-austerity/manuscript","json":"https://greyscienx.com/api/v1/research/emergency-ageing-austerity","pdf":"https://greyscienx.com/research/population-futures/emergency-ageing-austerity.pdf"}},{"id":"GSX:POP-006","slug":"the-price-of-another-child","title":"The Price of Another Child","primary_question":"When does fertility support become cheaper than financing demographic decline?","summary":"When fertility support becomes cheaper than financing demographic decline.","research_type":"exploratory_simulation","evidence_status":"modelled","series_slug":"population-futures","series_title":"Population Futures","version":"1.0","date_modified":"2026-09-28","links":{"html":"https://greyscienx.com/research/population-futures/the-price-of-another-child","markdown":"https://greyscienx.com/research/population-futures/the-price-of-another-child/markdown","manuscript":"https://greyscienx.com/api/v1/research/the-price-of-another-child/manuscript","json":"https://greyscienx.com/api/v1/research/the-price-of-another-child","pdf":"https://greyscienx.com/research/population-futures/the-price-of-another-child.pdf"}},{"id":"GSX:POP-007","slug":"the-hundred-year-life","title":"The Hundred-Year Life","primary_question":"How would education, work, housing, and family life be redesigned for lives of 100 to 120 years?","summary":"Education, work, housing and family life redesigned for 100–120 year lives.","research_type":"exploratory_simulation","evidence_status":"modelled","series_slug":"population-futures","series_title":"Population Futures","version":"1.0","date_modified":"2026-09-28","links":{"html":"https://greyscienx.com/research/population-futures/the-hundred-year-life","markdown":"https://greyscienx.com/research/population-futures/the-hundred-year-life/markdown","manuscript":"https://greyscienx.com/api/v1/research/the-hundred-year-life/manuscript","json":"https://greyscienx.com/api/v1/research/the-hundred-year-life","pdf":"https://greyscienx.com/research/population-futures/the-hundred-year-life.pdf"}},{"id":"GSX:POP-009","slug":"how-to-shrink-a-country-without-breaking-it","title":"How to Shrink a Country Without Breaking It","primary_question":"What happens to housing, cities, and public infrastructure under population contraction?","summary":"Housing, cities and public infrastructure under population contraction.","research_type":"exploratory_simulation","evidence_status":"modelled","series_slug":"population-futures","series_title":"Population Futures","version":"1.0","date_modified":"2026-09-28","links":{"html":"https://greyscienx.com/research/population-futures/how-to-shrink-a-country-without-breaking-it","markdown":"https://greyscienx.com/research/population-futures/how-to-shrink-a-country-without-breaking-it/markdown","manuscript":"https://greyscienx.com/api/v1/research/how-to-shrink-a-country-without-breaking-it/manuscript","json":"https://greyscienx.com/api/v1/research/how-to-shrink-a-country-without-breaking-it","pdf":"https://greyscienx.com/research/population-futures/how-to-shrink-a-country-without-breaking-it.pdf"}},{"id":"GSX:POP-010","slug":"the-scarce-worker-economy","title":"The Scarce-Worker Economy","primary_question":"Can automation, productivity, and immigration substitute for missing workers?","summary":"Automation, productivity and immigration as substitutes for missing workers.","research_type":"exploratory_simulation","evidence_status":"modelled","series_slug":"population-futures","series_title":"Population Futures","version":"1.0","date_modified":"2026-09-28","links":{"html":"https://greyscienx.com/research/population-futures/the-scarce-worker-economy","markdown":"https://greyscienx.com/research/population-futures/the-scarce-worker-economy/markdown","manuscript":"https://greyscienx.com/api/v1/research/the-scarce-worker-economy/manuscript","json":"https://greyscienx.com/api/v1/research/the-scarce-worker-economy","pdf":"https://greyscienx.com/research/population-futures/the-scarce-worker-economy.pdf"}},{"id":"GSX:POP-011","slug":"the-population-system","title":"The Population System","primary_question":"How do the population studies connect as one policy system?","summary":"A synthesis of the ten population studies as one connected policy system.","research_type":"exploratory_simulation","evidence_status":"modelled","series_slug":"population-futures","series_title":"Population Futures","version":"1.0","date_modified":"2026-09-28","links":{"html":"https://greyscienx.com/research/population-futures/the-population-system","markdown":"https://greyscienx.com/research/population-futures/the-population-system/markdown","manuscript":"https://greyscienx.com/api/v1/research/the-population-system/manuscript","json":"https://greyscienx.com/api/v1/research/the-population-system","pdf":"https://greyscienx.com/research/population-futures/the-population-system.pdf"}},{"id":"GSX:POP-012","slug":"extreme-fiscal-pressure","title":"Extreme Fiscal Pressure","primary_question":"How could emergency government measures introduced in 2050 alter the population system?","summary":"How emergency government measures introduced in 2050 could alter the population system.","research_type":"exploratory_simulation","evidence_status":"modelled","series_slug":"population-futures","series_title":"Population Futures","version":"1.0","date_modified":"2026-09-28","links":{"html":"https://greyscienx.com/research/population-futures/extreme-fiscal-pressure","markdown":"https://greyscienx.com/research/population-futures/extreme-fiscal-pressure/markdown","manuscript":"https://greyscienx.com/api/v1/research/extreme-fiscal-pressure/manuscript","json":"https://greyscienx.com/api/v1/research/extreme-fiscal-pressure","pdf":"https://greyscienx.com/research/population-futures/extreme-fiscal-pressure.pdf"}}],"related_questions":["Under what conditions does retirement at 60 remain financially viable?","How do ageing and lifetime finances constrain retirement at a fixed age?","How does an ageing electorate change the politics of public spending?","What happens to intergenerational transfers when the median voter is older?","How can an ageing-related fiscal deficit be closed?","What is the welfare comparison among emergency responses to demographic fiscal pressure?","What is the fiscal comparison between supporting another child and financing an older population?","How does population decline change the public cost of low fertility?"],"claims":[{"id":"GSX:POP-001:C01","claim":"In this funded-account model, a worker who starts at 25 on R30,000 a month, contributes 12 percent, and earns a 3 percent net real return exhausts a pension equal to 60 percent of final salary around age 70 if retirement begins at 60 and life lasts to 90.","study_id":"GSX:POP-001","study_title":"When Retirement Becomes Impossible","href":"https://greyscienx.com/research/population-futures/when-retirement-becomes-impossible/claims/C01"},{"id":"GSX:POP-004:C01","claim":"In the 2025 calibration, people aged 60 or older are 15.1 percent of adults but 20.7 percent of votes cast. Applying the 2024 age-turnout pattern produces a median voter aged 43, four years older than the median adult.","study_id":"GSX:POP-004","study_title":"The Politics of an Ageing Electorate","href":"https://greyscienx.com/research/population-futures/the-politics-of-an-ageing-electorate/claims/C01"},{"id":"GSX:POP-005:C01","claim":"Among five packages that each close a hypothetical R150 billion annual ageing gap, the balanced transition has the lowest modelled welfare-loss index, 64.5. The low-visible-pain package, which leans on inflation, diffuse cuts, and continuing borrowing, scores 107.3 and leaves about R720 billion of emergency debt after ten years.","study_id":"GSX:POP-005","study_title":"Emergency Ageing Austerity","href":"https://greyscienx.com/research/population-futures/emergency-ageing-austerity/claims/C01"},{"id":"GSX:POP-006:C01","claim":"In the average run, the median cost of one permanently additional birth ranges from about R720,000 for free childcare to R4.18 million for a parent tax exemption. The targeted family package costs about R780,000 per added birth and produces nearly 99,000 additional births per million prospective households. A cash top-up costs about R1.76 million per added birth and produces only about 12,000.","study_id":"GSX:POP-006","study_title":"The Price of Another Child","href":"https://greyscienx.com/research/population-futures/the-price-of-another-child/claims/C01"},{"id":"GSX:POP-007:C01","claim":"If a conventional life retires at 65 and the person lives to 120, retirement lasts 55 years and the modelled pension finances only 57 percent of the target income, even with uninterrupted employment.","study_id":"GSX:POP-007","study_title":"The Hundred-Year Life","href":"https://greyscienx.com/research/population-futures/the-hundred-year-life/claims/C01"},{"id":"GSX:POP-009:C01","claim":"In the central scenario, a 22.2 percent population decline by 2076 coincides with 3.5 percent more households. The same run can still produce a shortage of roughly 54,000 habitable homes after the city has lost 266,000 people.","study_id":"GSX:POP-009","study_title":"How to Shrink a Country Without Breaking It","href":"https://greyscienx.com/research/population-futures/how-to-shrink-a-country-without-breaking-it/claims/C01"},{"id":"GSX:POP-010:C01","claim":"In the average case, a smaller resident workforce can still coincide with real GDP at an index of 151, because output per worker rises about 57 percent. The total workforce ends at 11.60 million after 75,000 young immigrants a year and 700,000 additional older workers.","study_id":"GSX:POP-010","study_title":"The Scarce-Worker Economy","href":"https://greyscienx.com/research/population-futures/the-scarce-worker-economy/claims/C01"},{"id":"GSX:POP-011:C01","claim":"Demographic pressure, in this synthesis, is rarely a shortage of people in the abstract. It is a failure of timing, matching and institutions. Income can arrive after it is useful, workers can exist outside the jobs that need them, homes can stand in the wrong places, and reform can begin after the cheaper options have expired.","study_id":"GSX:POP-011","study_title":"The Population System","href":"https://greyscienx.com/research/population-futures/the-population-system/claims/C01"},{"id":"GSX:POP-012:C01","claim":"Every modelled path closes the first-year accounting gap of about R1.23 trillion. In the guardrailed case that ends in 2052, real output in 2080 is 1.2 percent below the no-shock path and the present value of lost output from 2050 to 2080 is R3.7 trillion.","study_id":"GSX:POP-012","study_title":"Extreme Fiscal Pressure","href":"https://greyscienx.com/research/population-futures/extreme-fiscal-pressure/claims/C01"}],"assumptions":[{"id":"GSX:POP-004:A02","name":"2024 age-turnout pattern","sensitivity":"high","study_id":"GSX:POP-004","href":"https://greyscienx.com/research/population-futures/the-politics-of-an-ageing-electorate"},{"id":"GSX:POP-001:A02","name":"Age-60 funded path","sensitivity":"high","study_id":"GSX:POP-001","href":"https://greyscienx.com/research/population-futures/when-retirement-becomes-impossible"},{"id":"GSX:POP-010:A02","name":"Average response","sensitivity":"high","study_id":"GSX:POP-010","href":"https://greyscienx.com/research/population-futures/the-scarce-worker-economy"},{"id":"GSX:POP-009:A02","name":"Central shrinkage path","sensitivity":"high","study_id":"GSX:POP-009","href":"https://greyscienx.com/research/population-futures/how-to-shrink-a-country-without-breaking-it"},{"id":"GSX:POP-012:A01","name":"Common 2050 shock","sensitivity":"high","study_id":"GSX:POP-012","href":"https://greyscienx.com/research/population-futures/extreme-fiscal-pressure"},{"id":"GSX:POP-007:A03","name":"Conventional three-stage life","sensitivity":"high","study_id":"GSX:POP-007","href":"https://greyscienx.com/research/population-futures/the-hundred-year-life"},{"id":"GSX:POP-007:A01","name":"Extended healthy adulthood","sensitivity":"high","study_id":"GSX:POP-007","href":"https://greyscienx.com/research/population-futures/the-hundred-year-life"},{"id":"GSX:POP-009:A01","name":"Hypothetical Gauteng-scale city-region","sensitivity":"high","study_id":"GSX:POP-009","href":"https://greyscienx.com/research/population-futures/how-to-shrink-a-country-without-breaking-it"}],"datasets":[{"id":"D01","title":"When Retirement Becomes Impossible","study_id":"GSX:POP-001","href":"https://greyscienx.com/research/population-futures/when-retirement-becomes-impossible/data"},{"id":"D01","title":"The Politics of an Ageing Electorate","study_id":"GSX:POP-004","href":"https://greyscienx.com/research/population-futures/the-politics-of-an-ageing-electorate/data"},{"id":"D01","title":"Emergency Ageing Austerity","study_id":"GSX:POP-005","href":"https://greyscienx.com/research/population-futures/emergency-ageing-austerity/data"},{"id":"D01","title":"The Price of Another Child","study_id":"GSX:POP-006","href":"https://greyscienx.com/research/population-futures/the-price-of-another-child/data"},{"id":"D01","title":"The Hundred-Year Life","study_id":"GSX:POP-007","href":"https://greyscienx.com/research/population-futures/the-hundred-year-life/data"},{"id":"D01","title":"How to Shrink a Country Without Breaking It","study_id":"GSX:POP-009","href":"https://greyscienx.com/research/population-futures/how-to-shrink-a-country-without-breaking-it/data"},{"id":"D01","title":"The Scarce-Worker Economy","study_id":"GSX:POP-010","href":"https://greyscienx.com/research/population-futures/the-scarce-worker-economy/data"},{"id":"D01","title":"The Population System","study_id":"GSX:POP-011","href":"https://greyscienx.com/research/population-futures/the-population-system/data"},{"id":"D01","title":"Extreme Fiscal Pressure","study_id":"GSX:POP-012","href":"https://greyscienx.com/research/population-futures/extreme-fiscal-pressure/data"}],"links":{"html":"https://greyscienx.com/topics/population-decline","json":"https://greyscienx.com/api/v1/topics/population-decline"}}