La science économique au service de la société
Katrin Millock

Katrin Millock

Professeure à PSE

Directrice de recherche CNRS

Campus Jourdan – 48 Boulevard Jourdan 75014 Paris

4e étage, bureau 20

Tél. 01 80 52 17 86

Site personnel
  • Environnement et ressources naturelles dans les pays en développement
  • Commerce, migrations et développement
  • Economie du changement climatique
  • Transition énergétique
  • Fiscalité verte

Recherche récente


Climate-induced migration

Climate variability has the potential to affect both international and internal migration profoundly. Earlier work finds that higher temperatures reduce agricultural yields, which in turn reduces migration rates in low-income countries, due to liquidity constraints. We test whether access to irrigation modulates this temperature–migration relationship, since irrigation buffers agricultural incomes from high temperatures. We regress measures of international and internal migration on decadal averages of temperature and rainfall, interacted with country-level data on irrigation and income. We find robust evidence that, for poor countries, irrigation access significantly offsets the negative effect of increasing temperatures on internal migration, as proxied by urbanisation rates. Our results demonstrate the importance of considering access to alternative adaptation strategies when analysing the temperature-migration relationship.


Migration is a common means of adaptation to weather shocks. Previous research has identified heterogeneous effects according to age, sex, and wealth, but little is still known about how marriage-related institutions affect such migration. Relying on a quasi-experimental identification strategy, we analyze marriage- and work-related migration in Malawi following large droughts, separating the effects for female and male migrants according to different age groups. The analysis based on stated motives of migration reveals marginal decreases in marriage-related migration among girls, but increases in marriage-related migration within districts for women in older age groups. We also find large increases in work-related between-district migration for boys, and to a smaller extent also for girls following severe drought. The results add to the evidence of the potentially adverse effects of migration as a coping mechanism following drought when other means of insurance do not exist.


  • Human migration in the era of climate change (with Cristina Cattaneo, Michel Beine, Christiane Froelich, Dominic Kniveton, Inmaculada Martinez-Zarzoso, Marina Mastrorillo, Etienne Piguet and Benjamin Schraven). Review of Environmental Economics and Policy 13(2), 189-206, 2019.

Migration is one response to climatic stress and shocks. In this article we review the recent literature across various disciplines on the effects of climate change on migration. We explore key features of the relationship between climate change and migration, distinguishing between fast-onset and slow-onset climatic events and examining the causes of heterogeneity in migratory responses to climate events. We also seek to shed light on the interactions between different types of adaptations to climate events as well as the mechanisms underlying the relationship between climate change and migration. Based on our review of the existing literature, we identify gaps in the literature and present some general policy recommendations and priorities for research on climate-induced migration.


We combine migration data from the 1991 and 2001 Indian Census with climate data to investigate the impact of climate variability on internal migration. The article makes four major contributions to the existing literature on macro-level migration flows. First, the use of the census data enables us to match the observed migration flows with relevant climatic factors prior to migration. Second, we introduce relevant meteorological indicators of climate variability, to measure the frequency, duration and magnitude of drought and excess precipitation based on the Standardized Precipitation Index. Third, we analyse bilateral migration rates in order to fully account for characteristics in both the origin and the destination states. We account for zero observations, which are frequent in bilateral data, by using a Pseudo Poisson Maximum Likelihood Estimator. Finally, we examine three possible channels through which climate variability could induce migration: average income, agriculture and urbanization. The estimation results show a direct effect of drought frequency in the origin state on inter-state migration in India. The magnitude of drought is also important in explaining the indirect effect going through the impact of climate variability on the income from the agricultural sector. The effect of drought frequency is higher for rural out-migration flows compared to the effect on total inter-state migration. The results are robust to alternative specifications with bilateral fixed effects and to the inclusion of irrigation rates. 


The concept of environmental migrants occurs frequently in the policy debate, in particular with regard to climate change and the incidence of such migration in low-income countries. This article reviews the economic studies of environmentally induced migration. It includes recent empirical analyses that try to link environmental change to migration flows and the spatial distribution of population. A consensus seems to emerge that there is little likelihood of large increases in international migration flows due to climate variability. The evidence to date shows that regional migration will be affected, however, either on the African continent or internally, within country borders. Theoretically, environmentally induced migration can be analyzed using different frameworks: the classical Harris-Todaro model of rural-urban migration, new economic geography models, models grounded in environmental economics of pollution externalities with free factor mobility, and the new economics of labor migration. I review some of the latest attempts to analyze environmentally induced migration theoretically and the policy-relevant conclusions that can be drawn. 


Technology adoption and diffusion


Accelerating the diffusion of climate-friendly technologies: a network perspective

(with Solmaria Halleck Vega and Antoine Mandel). Ecological Economics 152, 235-245, 2018.


We introduce a methodology to estimate the determinants of the formation of technology diffusion networks from the patterns of technology adoption. We apply this methodology to wind energy, which is one of the key technologies in climate change mitigation. Our results emphasize that, in particular, long-term relationships as measured by economic integration are key determinants of technological diffusion. Specific support measures are less relevant, at least to explain the extensive margin of diffusion. Our results also highlight that the scope of technological diffusion is much broader than what is suggested by the consideration of CDM projects alone, which are particularly focused on China and India. Finally, the network of technological diffusion inferred from our approach highlights the central role of European countries in the diffusion process and the absence of large hubs among developing countries.



Papers in submission or in progress


Flood risk information: Evidence from Paris housing markets

(with Edwige Dubos-Paillard and Emmanuelle Lavaine)


Water inequality and conflict (with Stefanija Veljanoska)


Multimodal adaptation (with Tristan du Puy and Jérémie Gignoux)