Hallegatte, Stéphane

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Green growth, Climate change, Urban development
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Last updated: March 29, 2024
Stéphane Hallegatte is a Senior Climate Change Adviser at the World Bank. He joined the World Bank in 2012 after 10 years of academic research in environmental economics and climate science for Météo-France, the Centre International de Recherche sur l’Environnement et le Développement, and Stanford University. His research interests include the economics of natural disasters and risk management, climate change adaptation, urban policy and economics, climate change mitigation, and green growth. Mr. Hallegatte was a lead author of the 5th Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). He is the author of dozens of articles published in international journals in multiple disciplines and of several books, including Green Economy and the Crisis: 30 Proposals for a More Sustainable France , Risk Management: Lessons from the Storm Xynthia , and Natural Disasters and Climate Change: An Economic Perspective . He also co-led the World Bank reports Inclusive Green Growth: The Pathway to Sustainable Development , published in 2012 and Decarbonizing Development in 2015, and was member of the core writing team of the 2014 World Development Report Risk and Opportunity: Managing Risks for Development . Most recently, he led the World Bank reports Shock Waves: Managing the Impacts of Climate Change on Poverty , Unbreakable: Building the Resilience of the Poor in the Face of Natural Disasters , and Lifelines: the Resilient Infrastructure Opportunity. He was the team leader for the World Bank Group Climate Change Action Plan, a large internal coordination exercise to determine and explain how the Group will support countries in their implementation of the Paris Agreement. Mr. Hallegatte holds engineering degrees from the Ecole Polytechnique (Paris) and the Ecole Nationale de la Météorologie (Toulouse), a master's degree in meteorology and climatology from the Université Paul Sabatier (Toulouse) and a Ph.D in economics from the Ecole des Hautes Etudes en Sciences Sociales (Paris).
Citations 2007 Scopus

Publication Search Results

Now showing 1 - 10 of 75
  • Publication
    How Delayed Learning about Climate Uncertainty Impacts Decarbonization Investment Strategies
    (Washington, DC: World Bank, 2024-03-29) Bauer, Adam Michael; McIsaac, Florent; Hallegatte, Stéphane
    The Paris Agreement established that global warming should be limited to “well below” 2◦C and encouraged efforts to limit warming to 1.5◦C. Achieving this goal presents a significant challenge, especially given the presence of (i) economic inertia and adjustment costs, which penalize a swift transition away from fossil fuels, and (ii) climate uncertainty that, for example, hinders the ability to predict the amount of emissions that can be emitted before a given temperature target is passed, which is often referred to as the remaining carbon budget. This paper presents a modeling framework that explores optimal decarbonization investment strategy when both delayed learning about the remaining carbon budget and adjustment costs are present. The findings show that delaying learning about the remaining carbon budget impacts investment in three ways: (i) the cost of policy increases, especially when adjustment costs are present; (ii) abatement investment is front-loaded relative to the certainty policy; and (iii) the sectoral allocation of investment changes to favor declining investment pathways rather than bell-shaped paths. The latter effect is especially pronounced in hard-to-abate sectors, such as heavy industry. Each of the effects can be traced back to the carbon price distribution inheriting a “heavy tail” when the remaining carbon budget is learned later in the century. The paper highlights how climate uncertainty and adjustment costs combined result in a more aggressive least-cost strategy for decarbonization investment.
  • Publication
    Does Global Warming Worsen Poverty and Inequality? An Updated Review
    (Washington, DC: World Bank, 2024-02-08) Trinh, Trong-Anh; Dang, Hai-Anh H.; Hallegatte, Stéphane
    This paper offers an updated and comprehensive review of recent studies on the impact of climate change, particularly global warming, on poverty and inequality, paying special attention to data sources as well as empirical methods. While studies consistently find negative impacts of higher temperature on poverty across different geographical regions, with higher vulnerability especially in poorer Sub-Saharan Africa, there is inconclusive evidence on climate change impacts on inequality. Further analysis of a recently constructed global database at the subnational unit level derived from official national household income and consumption surveys shows that temperature change has larger impacts in the short term and more impacts on chronic poverty than transient poverty. The results are robust to different model specifications and measures of chronic poverty and are more pronounced for poorer countries. The findings offer relevant inputs into current efforts to fight climate change.
  • Publication
    Counting People Exposed to, Vulnerable to, or at High Risk From Climate Shocks: A Methodology
    (World Bank, Washington, DC, 2023-12-04) Doan, Miki Khanh; Hill, Ruth; Hallegatte, Stephane; Corral, Paul; Brunckhorst, Ben; Nguyen, Minh; Freije-Rodriguez, Samuel; Naikal, Esther
    Based on global datasets, 4.5 billion people were exposed to extreme weather events (flood, drought, cyclone, or heatwave) in 2019, an increase from 4 billion in 2010. Among exposed people in 2019, 2.3 billion people lived with less than $6.85 per day and about 400 million lived in extreme poverty (on less than $2.15 per day). This paper presents a methodology to estimate the number of people who are at high risk from extreme weather events, defined as the people who are exposed to these events and highly vulnerable to them. Vulnerability is proxied by a set of indicators measuring (1) the physical propensity to experience severe losses (proxied by the lack of access to basic infrastructure services, here water and electricity) and (2) the inability to cope with and recover from losses (proxied by low income, not having education, not having access to financial services and not having access to social protection). Estimates from 75 countries for which data on all indicators are available suggest that, in 2019, 42 percent of the total population (and 70 percent of people exposed) are at high risk from extreme weather shocks, if one indicator is enough to be considered as highly vulnerable. If high vulnerability is defined based on being vulnerable on two dimensions or more, then 12 percent of the total population (and 20 percent of people exposed) are at high risk from extreme weather shocks. The trend between 2010 and 2019 can be explored in a subset of countries covering 60 percent of the world population. In these countries, even though the population exposed to extreme weather events has been increasing, the number of people at high risk has declined. The exception is Sub-Saharan Africa where the number of people at high risk has increased between 2010 and 2019.
  • Publication
    Within Reach: Navigating the Political Economy of Decarbonization
    (Washington, DC: World Bank, 2023-11-16) Hallegatte, Stéphane; Godinho, Catrina; Rentschler, Jun; Avner, Paolo; Dorband, Ira Irina; Knudsen, Camilla; Lemke, Jana; Mealy, Penny
    Despite global commitments made through the Paris Agreement in 2015 to combat climate change, their translation into national policies has been slow, raising concerns about the feasibility of achieving climate targets. While policies face many obstacles, the political economy is one of the primary impediments to climate action, and urgency to reduce emissions makes slow and gradual approach increasingly insufficient. The report attempts to identify key political economy barriers and explore options to address them through the 4i Framework, considering how institutions, interests, ideas, and influence affect the political economy. The report offers a practical guide to help countries address political economy barriers when implementing climate policies with three prongs: (1) Climate Governance: governments can adapt their institutional framework, in ways that fit with the pre-existing political economy and moving from opportunistic and unstable to strategic and stable climate institutions. Establishing strategic climate governance institutions – such as climate change framework laws, long-term strategies, or just transition frameworks - can alter the political economy, set clear objectives, improve coordination across actors, and improve the ability to monitor progress and hold decisionmakers accountable. (2) Policy Sequencing: policies can be prioritized and sequenced based on dynamic efficiency, considering not only the economic costs and benefits, but also their feasibility and long-term impact on the political economy. The Climate Policy Feasibility Frontier tool can help identify policies that can overcome short-term political economy obstacles, and at the same time improve capacities and change the political economy to facilitate further climate action. (3) Policy Design and Engagement, considers the effective implementation of climate reforms by tactically navigating political economy constraints. This involves engaging citizens to create process legitimacy and reducing and managing distributional effects, not only across but also within income groups.
  • Publication
    Climate Policy and Inequality in Urban Areas: Beyond Incomes
    (World Bank, Washington, DC, 2022-09) Liotta, Charlotte; Avner, Paolo; Viguié, Vincent; Selod, Harris; Hallegatte, Stephane; Avner, Paolo
    Opposition to climate policies seems to arise, at least partly, from their effects on inequality. However, so far, the impact of climate policies on inequality has mainly been studied through the lens of income inequality, and their spatial dimension is poorly understood. This paper, using Cape Town, South Africa, as a case study, investigates the impact of a fuel tax on both spatial and income inequalities. It uses a model derived from the standard urban economics land use model, accounting for four income classes and four housing types. This modeling framework allows decomposing the impacts of the tax by income class, housing type, and housing location. The analysis also decomposes the impacts of the tax over different timeframes, assuming that households and developers progressively adapt to the tax. The findings reveal strong evidence that in the short term, there are both income and spatial inequalities, with households being more negatively impacted by the fuel tax if they earn low incomes or live far from employment centers. In the medium and long term, these inequalities persist: the poorest households, living in informal settlements or subsidized housing, have few or no ways to adapt to changes in fuel prices by changing housing type, adjusting their dwelling sizes or locations, or shifting transportation modes. Low-income households living in formal housing also remain impacted by the tax over the long term due to complex effects driven by the competition with richer households on the housing market. Complementary policies promoting a functioning labor market that allows people to change jobs easily, affordable public transportation, or subsidies helping low-income households to rent houses closer to employment centers will be key to enable the social acceptability of climate policies.
  • Publication
    Rapid Urban Growth in Flood Zones: Global Evidence since 1985
    (World Bank, Washington, DC, 2022-04) Rentschler, Jun; Marconcini, Mattia; Su, Rui; Strano, Emanuele; Hallegatte, Stephane; Riom, Capucine; Avner, Paolo
    As countries rapidly urbanize, settlements are expanding into hazardous flood zones. This study provides a global analysis of spatial urbanization patterns and the evolution of flood exposure between 1985 and 2015. Using high-resolution annual data, it shows that settlements across the world grew by 85 percent to over 1.28 million square kilometers. In the same period, settlements exposed to the highest flood hazard level increased by 122 percent. In many regions, risky growth is outpacing safe growth, particularly in East Asia, where high-risk settlements have expanded 60 percent faster than safe ones. Developing countries are driving the recent growth of flood exposure: 36,500 square kilometers of settlements were built in the world’s highest-risk zones since 1985–82 percent of which are in low- and middle-income countries. In comparison, recent growth in high-income countries has been relatively slow and safe. These results document a divergence in countries’ exposure to flood hazards. Rather than adapting their exposure to climatic hazards, many countries are actively increasing their exposure.
  • Publication
    Macroeconomic Consequences of Natural Disasters: A Modeling Proposal and Application to Floods and Earthquakes in Turkey
    (Washington, DC: World Bank, 2022-02-22) Hallegatte, Stephane; Mcisaac, Florent John
    Turkey is vulnerable to natural disasters that can generate substantial damages to public and private sector infrastructure capital. Earthquakes and floods are the most frequent hazards today, and flood risks are expected to increase with climate change. To ensure stability and growth and minimize the welfare impact of these disasters, these shocks need to be managed and accounted for in macro-fiscal and monetary policy. To support this process, the World Bank Macrostructural Model is adapted to assess the macroeconomic effects of natural (geophysical or climate-related) disasters. The macroeconomic model is extended on several fronts: (1) a distinction is made between infrastructure and non-infrastructure capital, with complementary or substitutability between the two categories; (2) the production function is adjusted to account for short-term complementarity across capital assets; (3) the reconstruction process is modeled in a way that accounts for post-disaster constraints, with distinct processes for the reconstruction of public and private assets. The results show that destroyed infrastructure capital makes the remaining non-infrastructure capital less productive, which means that disasters reduce the total stock of capital, but also its productivity. The welfare impact of a disaster—proxied by the discounted consumption loss—is found to increase non-linearly with direct asset losses. Macroeconomic responses reduce the welfare impact of minor disasters but magnify it when direct asset losses exceed the economy’s absorption capacity. The welfare impact also depends on the pre-existing economic situation, the ability of the economy to reallocate resources toward reconstruction, and the response of the monetary policy. Appropriate macro-fiscal and monetary policies offer cost-effective opportunities to mitigate the welfare impact of major disasters.
  • Publication
    Natural Disasters, Poverty and Inequality: New Metrics for Fairer Policies
    (Taylor and Francis, 2021-10-28) Hallegatte, Stephane
    Conventional risk assessments underestimate the human and macroeconomic costs of disasters, leading to inefficient risk management strategies. This happens because conventional assessments focus on asset losses, neglecting important relationships between vulnerability and development. When affected by a hazard, poor households take longer to recover from disasters and are more likely to face long-term consequences. Forced to manage trade-offs between essential consumption and reconstruction, these households are more likely to face persistent health or education costs. This chapter proposes a review of existing research into the natural disaster-poverty-inequality nexus and the various metrics that can be used to measure disaster impacts, such as recovery times, economic (income or consumption) losses, poverty incidence, inequality, and welfare or well-being losses. Each of these metrics provides a different perspective on disaster costs and suggest different spatial and sectoral priorities for action. Focusing on the concepts of well-being losses and socioeconomic resilience, this chapter shows how more comprehensive accounting of disaster impacts can better inform disaster risk management and climate change adaptation strategies and support their integration into development and poverty-reduction policies.
  • Publication
    Floods and Their Impacts on Firms: Evidence from Tanzania
    (World Bank, Washington, DC, 2021-09) Rentschler, Jun; Thies, Stephan; De Vries Robbe, Sophie; Erman, Alvina; Hallegatte, Stéphane
    This study explores how businesses in Tanzania are impacted by floods, and which strategies they use to cope and adapt. These insights are based on firm survey data collected in 2018 using a tailored questionnaire, covering a sample of more than 800 firms. To assess the impact of disasters on businesses, the study considers direct damages and indirect effects through infrastructure systems, supply chains, and workers. While direct on-site damages from flooding can be substantial, they tend to affect a relatively small share of firms. Indirect impacts of floods are more prevalent and sizable. Flood-induced infrastructure disruptions—especially electricity and transport—obstruct the operations of firms even when they are not directly located in flood zones. The effects of such disruptions are further propagated and multiplied along supply chains. The study estimates that supply chain multipliers are responsible for 30 to 50 percent of all flood-related delivery delays. To cope with these impacts, firms apply a variety of strategies. Firms mitigate supply disruptions by adjusting the size and geographical reach of their supply networks, and by adjusting inventory holdings. By investing in costly backup capacity (such as water tanks and electricity generators), firms mitigate the impact of infrastructure disruptions. The study estimates that only 13 percent of firms receive government support in the aftermath of floods.
  • Publication
    Flood Protection and Land Value Creation: Not All Resilience Investments Are Created Equal
    (World Bank, Washington, DC, 2021-07) Avner, Paolo; Viguié, Vincent; Jafino, Bramka Arga; Hallegatte, Stephane; Avner, Paolo
    This paper investigates the land value creation potential from flood mitigation investments in a theoretical and applied setting, using the urban area of Buenos Aires as a case study. It contributes to the literature on the wider economic benefits of government interventions and the dividends of resilience investments. Using a simple urban economics framework that represents land and housing markets, it finds that not all flood mitigation interventions display the same potential for land value creation: where land is more valuable (city centers for example), the benefits of resilience are higher. The paper also provides ranges for land value creation potential from the flood mitigation works in Buenos Aires under various model specifications. Although the estimates vary largely depending on model parameters and specifications, in many cases the land value creation would be sufficient to justify the investments. This result is robust even in the closed city configuration with conservative flood damage estimates, providing that the parameters remain reasonably close to the values obtained from the calibration. Finally, acknowledging that fully calibrating and running an urban simulation model is data greedy and time intensive—even a simple model as proposed here—this research also proposes reduced form expressions that can provide approximations for land value creation from flood mitigation investments and can be used in operational contexts.