Skip to main content
Log in

When nature rebels: international migration, climate change, and inequality

Journal of Population Economics Aims and scope Submit manuscript

Cite this article


We study climate change and international migration in a two-country overlapping generations model with endogenous climate change. Our main findings are that climate change increases migration; small impacts of climate change have significant impacts on the number of migrants; a laxer immigration policy increases long-run migration, aggravates climate change, and increases north–south inequality if climate change impacts are not too small; and a greener technology reduces emissions, long-run migration, and inequality if the migrants’ impact to overall climate change is large. The preference over the policies depends on whether the policy maker targets inequality, wealth, the environment, or the number of migrants.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions


  1. The literature has also focused on the impact of migration on the economy of the destination and origin countries. Migration can affect labor market outcomes such as wages (Borjas 2003) or unemployment (Bencivenga and Smith 1997), pension systems (Razin and Sadka 1999), or human capital formation (Vidal 1998) and growth (Beine et al. 2001).

  2. Modelling migration decisions in this way is common in the literature and implies that a decline in southern income stimulates migration pressure. However, it is important to have in mind that a decreasing income in low-income countries may also lead to a reduction in the number of emigrants if liquidity constraints become more binding. We thank an anonymous referee for pointing out this fact.

  3. It should be clear that this result only holds if preference and production parameters are the same and in the absence of any taxation or subsidy.

  4. Proof: We check whether the equilibrium condition can exist by varying M along its domain \([0,\bar{L}_S]\). We get \(\lim_{M\to0}x^{1-\alpha}\!A_{\!N}L^{ \alpha+\beta-1}_N\!>\!\lim_{M\to0}A_{\!S}L^{\alpha+\beta-1}_S\!>\!0\), and \(\lim_{M\to \bar{L}_S}x^{1-\alpha}A_NL^{\alpha+\beta-1}_N<\) \(\lim_{M\to\bar{L} _S}A_SL^{\alpha+\beta-1}_S\). Since \(x^{1-\alpha}A_NL^{\alpha+\beta-1}_N\) is a monotonically decreasing function of M and since \(A_SL^{\alpha+\beta-1}_S \) is a monotonically increasing function of M from a positive number to infinity, we conclude that a unique steady state exists if \(x^{1-\alpha}A_N \bar{L}^{\alpha+\beta-1}_N>A_S\bar{L}^{\alpha+ \beta-1}_S\).

  5. Under CRTS, no non-trivial steady state exists since \(x^{1-\alpha}A_N= A_S\) is a knife-edge condition. Thus, we have either no migration or complete migration.

  6. Proof: limM→0 LHS > limM→0 RHS > 0, and \(\lim_{M\to\bar{L} _S}LHS<\lim_{M\to\bar{L}_S}RHS\).

  7. In fact, we have \({\frac{\partial M^{acm}}{\partial A_S}}= {-{\frac{1 }{1-\alpha-\beta}}A^{\frac{2-\alpha-\beta}{\alpha+\beta-1}}_S {\frac{ (x^{1-\alpha}A_N)^{\frac{1}{\alpha+\beta-1}}(\bar{L}_S+\bar{L}_N)}{\left(A^{ \frac{1}{\alpha+\beta-1}}_S+(x^{1-\alpha}A_N)^{\frac{1}{\alpha+\beta-1}}\right) ^2}}<0.}\)

  8. While policies may certainly bear costs at the time they are implemented, it could be argued that these costs will be zero in the long run. This could be the case if one considers, for example, R&D expenditure in emission reductions: If a greener technology is developed once, then it is clear that further R&D expenditure is not necessary in the long run. Similarly, immigration policy that leads to a higher probability of obtaining a job for the migrants only requires a discussion in the parliament. The long-run costliness of policies will, however, not change the results. A formal demonstration is available on request from the authors.

  9. We neglect the fact that the government may wish to raise taxes but not invest everything in border controls, respectively, green technologies, an assumption equivalent to the no-Ponzi scheme assumption.

  10. It is straightforward to see that the direct impact of taxes on steady-state production is negative, since \(Y_N=\big[\big({\frac{\rho}{1+\rho}}\beta\big) ^\alpha (1-\tau)^\alpha A_NL_N^\beta\big]^{\frac{1}{1-\alpha}}\).

  11. Imagine the following functional form for the immigration costs x(τ x Y N ) : \(x={\frac{\bar{x}}{1+a\tau_xY_N}}\), where a > 0 is a parameter and \(\bar{x }\) are immigration costs without government intervention. Then, condition 35 drops down to τ x  < 1 − α. Thus, the northern government can improve the welfare of its citizens if taxes on production are not larger than the share of non-capital revenues in production.

  12. If we take the same functional form as in endnote 11 for the immigration costs, then it is easy to show that a sufficient condition for \({\frac{d M^{acm}}{d \tau_x}}<0\) is τ x  < 1 − α.

  13. Alternatively, imposing \(\bar{\mu}_{{\rm NAM}}\) and \(\bar{\mu}_{{\rm EU}}\) to be equal to what the data suggest for μ could be interpreted to reflect a situation where existing taxes on production are implicitly taken into account in the data. Our analysis would then be to focus on how the introduction of an additional tax rate on production should be allocated between border controls and clean technologies.


  • Afolayan AA, Adelekan IO (1999) The role of climatic variations on migration and human health in Africa. The Environmentalist 18(4):213–318

    Article  Google Scholar 

  • Basu S, Fernald JG (1997) Returns to scale in U.S. Production: estimates and implications. J Polit Econ 105(2):249–83

    Article  Google Scholar 

  • Beine M, Docquier F, Rapoport H (2001) Brain drain and economic growth: theory and evidence. J Dev Econ 64(1):275–289

    Article  Google Scholar 

  • Bencivenga V, Smith B (1997) Unemployment, migration, and growth. J Polit Econ 105(3):582

    Article  Google Scholar 

  • Black R (2001) Environmental refugees: myth or reality? Office of the United Nations High Commissioner for Refugees, evaluation and policy analysis unit. UNHCR

  • Borjas GJ (2003) The labor demand curve is downward sloping: reexamining the impact of immigration on the labor market. Q J Econ 118(4):1335–1374

    Article  Google Scholar 

  • Brown B (2000) Southern Idaho fertilizer guide: onions. Bull. CIS 1081. College of Agriculture and Agricultural Experiment Station University of Idaho, Moscow

    Google Scholar 

  • Brown B, Hornbacher A, Naylor D (1988) Sulfur-coated urea as a slow release nitrogen source for onions. Cooperative Extension Service, University of Idaho, College of Agriculture

  • Chen M, Xu C, Wang R (2007) Key natural impacting factors of China’s human population distribution. Popul Environ 28(3):187–200

    Article  Google Scholar 

  • Christie L (2006) Growth states: Arizona overtakes Nevada. CNN, 25 December 2006

  • CIESIN (2006) Pilot 2006 environmental performance index (EPI) Yale center for environmental law and policy and center for international earth science information network (CIESIN). Yale University

  • Cigno A (1981) Growth with exhaustible resources and endogenous population. Rev Econ Stud 48(2):281–287

    Article  Google Scholar 

  • Crettez B, Michel P, Vidal J (1996) Time preference and labour migration in an OLG model with land and capital. J Popul Econ 9(4):387–403

    Google Scholar 

  • de la Croix D, Michel P (2002) A theory of economic growth: dynamics and policy in overlapping generations. Cambridge University Press, Cambridge

    Book  Google Scholar 

  • Docquier F, Marfouk A (2006) International migration by educational attainment (1990–2000) - release 1.1. In: Ozden C, Schiff M (eds) International migration, remittances and development. McMillan and Palgrave, New York

    Google Scholar 

  • Ezra M (2001) Ecological degradation, rural poverty, and migration in ethiopia: a contextual analysis. Policy research division working paper no. 149. Population Council, New York

    Google Scholar 

  • Facchini G, Willmann G (2005) The political economy of international factor mobility. J Int Econ 67(1):201–219

    Article  Google Scholar 

  • FAO (2004) The state of food and agriculture 2003–2004. Agriculture Series (SOFA). Food and Agriculture Organization (FAO), Rome

    Google Scholar 

  • FIG (2006) The contribution of the surveying profession to disaster risk management. International Federation of Surveyors (FIG), FIG Publication No.38

  • Flavin C, Tunali O (1998) Ein Klima der Hoffnung. Worldwatch paper

  • Galor O (1986) Time preference and international labor migration. J Econ Theory 38(1):1–20

    Article  Google Scholar 

  • Ghatak S, Levine P, Price S (1996) Migration theories and evidence: an assessment. J Econ Surv 10(2):159–198

    Article  Google Scholar 

  • Hahn F, Solow R (1995) A critical essay on modern macroeconomic theory. MIT, Cambridge

    Google Scholar 

  • Harris J, Todaro M (1970) Migration, unemployment and development: a two-sector analysis. Am Econ Rev 60(1):126–142

    Google Scholar 

  • Henry S, Schoumaker B, Beauchemin C (2004) The impact of rainfall on the first out-migration: a multi-level event-history analysis in Burkina Faso. Popul Environ 25(5):423–460

    Article  Google Scholar 

  • Hugo G (1996) Environmental concerns and international migration. Int Migr Rev 30(1):105–131

    Article  Google Scholar 

  • IEA (2004) International energy annual 2004. International energy agency

  • INCCCD (1994) The almeria statement on desertification and migration. Intergovernmental negotiating committee for a convention to combat desertification, Châtelaine, Switzerland

  • IPCC (2001) Third assessment report: climate change 2001. Intergovernmental panel on climate change

  • IPCC (2007) Climate change 2007—impacts, adaptation and vulnerability. Intergovernmental panel on climate change. Cambridge University Press, Cambridge

    Google Scholar 

  • Kaye L (1994) The reckoning. Far East Econ Rev 157(24):24–30

    Google Scholar 

  • McLeman R (2006) Migration out of 1930s rural Eastern Oklahoma: insights for climate change research. Great Plains Q 26(1):27–40

    Google Scholar 

  • Millenium Ecosystem Assessment (2005) Ecosystems and human well-being: general synthesis. Millenium ecosystem assessment (MA). Island, Washington DC

    Google Scholar 

  • Morris S, Neidecker-Gonzales O, Carletto C, Munguia M, Medina J, Wodon Q (2002) Hurricane mitch and the livelihoods of the rural poor in honduras. World Dev 30(1):49–60

    Article  Google Scholar 

  • Myers N (1996) Environmentally-induced displacements: the state of the art. In: Environmentally-induced population displacements and environmental impacts resulting from mass migration. International symposium Geneva, 21–24 April 1996, refugee policy group, International Organization for Migration (IOM)

  • Narayanan B, Walmsley T (2008) Global trade, assistance, and production: the GTAP 7 data base. Center for global trade analysis, Purdue University

    Google Scholar 

  • Razin A, Sadka E (1999) Migration and pension with international capital mobility. J Public Econ 74(1):141–150

    Article  Google Scholar 

  • Rosenzweig C, Hillel D (1993) The dust bowl of the 1930s: analog of greenhouse effect in the great plains? J Environ Q 22(1):9–22

    Article  Google Scholar 

  • Stern N (2007) The economics of climate change: the stern review. Cambridge University Press, Cambridge

    Google Scholar 

  • Swart R, Berk M, Janssen M, Kreileman E, Leemans R (1998) The safe landing analysis: risks and trade-offs in climate change. In: Alcamo J, Leemans R, Kreileman E (eds) Global change scenarios of the 21st century. Results from the IMAGE 2.1 Model. Pergamon and Elsevier Science, London, pp 193–218

    Google Scholar 

  • United Nations (2008) World population PROSPECTS: the 2008 revision. Department of Economic and Social Affairs, United Nations

    Google Scholar 

  • Vidal J (1998) The effect of emigration on human capital formation. J Popul Econ 11(4):589–600

    Article  Google Scholar 

  • Warren R, Arnell N, Nicholls R, Levy P, Price J (2006) Understanding the regional impacts of climate change. Research report prepared for the stern review on the economics of climate change, Working Paper No. 90, Tyndall Centre for Climate Change Research

  • WDI (2007) World development indicators online. Development data group. World Bank, Washington, DC

    Google Scholar 

  • WHO (1996) The world health report 1996: fighting disease, fostering development. World Health Organization, Geneva

    Google Scholar 

Download references


We kindly acknowledge useful comments from two anonymous referees, Raouf Boucekkine and David de la Croix. The second author is grateful for financial support from the Chair for Business Economics and the Chair EDF-Sustainable Development at the Ecole Polytechnique.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Luca Marchiori.

Additional information

Responsible editor: Alessandro Cigno

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Marchiori, L., Schumacher, I. When nature rebels: international migration, climate change, and inequality. J Popul Econ 24, 569–600 (2011).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


JEL Classification