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 28
  • Publication
    Carbon Price Efficiency : Lock-in and Path Dependence in Urban Forms and Transport Infrastructure
    (World Bank, Washington, DC, 2014-06) Avner, Paolo; Rentschler, Jun; Hallegatte, Stéphane; Avner, Paolo
    This paper investigates the effect of carbon or gasoline taxes on commuting-related CO2 emissions in an urban context. To assess the impact of public transport on the efficiency of the tax, the paper investigates two exogenous scenarios using a dynamic urban model (NEDUM-2D) calibrated for the urban area of Paris: (i) a scenario with the current dense public transport infrastructure, and (ii) a scenario without. It is shown that the price elasticity of CO2 emissions is twice as high in the short run if public transport options exist. Reducing commuting-related emissions thus requires lower (and more acceptable) tax levels in the presence of dense public transportation. If the goal of a carbon or gasoline tax is to change behaviors and reduce energy consumption and CO2 emissions (not to raise revenues), then there is an incentive to increase the price elasticity through complementary policies such as public transport development. The emission elasticity also depends on the baseline scenario and is larger when population growth and income growth are high. In the longer run, elasticities are higher and similar in the scenarios with and without public transport, because of larger urban reconfiguration in the latter scenario. These results are policy relevant, especially for fast-growing cities in developing countries. Even for cities where emission reductions are not a priority today, there is an option value attached to a dense public transport network, since it makes it possible to reduce emissions at a lower cost in the future.
  • Publication
    A Note on the Economic Cost of Climate Change and the Rationale to Limit it Below 2°C
    (World Bank, Washington, DC, 2010-01) Hallegatte, Stephane; Hourcade, Jean-Charles
    This note highlights a major reason to limit climate change to the lowest possible levels. This reason follows from the large increase in uncertainty associated with high levels of warming. This uncertainty arises from three sources: the change in climate itself, the change s impacts at the sector level, and their macroeconomic costs. First, the greater the difference between the future climate and the current one, the more difficult it is to predict how local climates will evolve, making it more difficult to anticipate adaptation actions. Second, the adaptive capacity of various economic sectors can already be observed for limited warming, but is largely unknown for larger changes. The larger the change in climate, therefore, the more uncertain is the final impact on economic sectors. Third, economic systems can efficiently cope with sectoral losses, but macroeconomic-level adaptive capacity is difficult to assess, especially when it involves more than marginal economic changes and when structural economic shifts are required. In particular, these shifts are difficult to model and involve thresholds beyond which the total macroeconomic cost would rise rapidly. The existence of such thresholds is supported by past experiences, including economic disruptions caused by natural disasters, observed difficulties funding needed infrastructure, and regional crises due to rapid economic shifts induced by new technologies or globalization. As a consequence, larger warming is associated with higher cost, but also with larger uncertainty about the cost. Because this uncertainty translates into risks and makes it more difficult to implement adaptation strategies, it represents an additional motive to mitigate climate change.
  • Publication
    An Exploration of the Link between Development, Economic Growth, and Natural Risk
    (World Bank, Washington, DC, 2012-10) Hallegatte, Stephane
    This paper investigates the link between development, economic growth, and the economic losses from natural disasters in a general analytical framework, with an application to hurricane flood risks in New Orleans. It concludes that where capital accumulates through increased density of capital at risk in a given area, and the costs of protection therefore increase more slowly than capital at risk, (i) protection improves over time and the probability of disaster occurrence decreases; (ii) capital at risk -- and thus economic losses in case of disaster -- increases faster than economic growth; (iii) increased risk-taking reinforces economic growth. In this context, average annual losses from disasters grow with income, and they grow faster than income at low levels of development and slower than income at high levels of development. These findings are robust to a broad range of modeling choices and parameter values, and to the inclusion of risk aversion. They show that risk-taking is both a driver and a consequence of economic development, and that the world is very likely to experience fewer but more costly disasters in the future. It is therefore critical to increase economic resilience through the development of stronger recovery and reconstruction support instruments.
  • Publication
    Decarbonizing Development: Three Steps to a Zero-Carbon Future
    (Washington, DC: World Bank, 2015-06) Fay, Marianne; Hallegatte, Stephane; Vogt-Schilb, Adrien; Rozenberg, Julie; Narloch, Ulf; Kerr, Tom
    The science is unequivocal: stabilizing climate change implies bringing net carbon emissions to zero. And this must be done by 2100 if we are to keep climate change anywhere near the 2 C. degree warming that world leaders have set as the maximum acceptable limit. Decarbonizing Development looks at what it would take to decarbonize the world economy by 2100 in a way that is compatible with countries’ broader development goals. It argues that the following are needed: Act early with an eye on the end-goal; Go beyond prices with a policy package that triggers changes in investment patterns, technologies and behaviors; Mind the political economy and smooth the transition for those who stand to be most affected.
  • Publication
    Assessing Socioeconomic Resilience to Floods in 90 Countries
    (World Bank, Washington, DC, 2016-05) Hallegatte, Stephane; Vogt-Schilb, Adrien
    This paper presents a model to assess the socioeconomic resilience to natural disasters of an economy, defined as its capacity to mitigate the impact of disaster-related asset losses on welfare, and a tool to help decision makers identify the most promising policy options to reduce welfare losses due to floods. Calibrated with household surveys, the model suggests that welfare losses from the July 2005 floods in Mumbai were almost double the asset losses, because losses were concentrated on poor and vulnerable populations. Applied to river floods in 90 countries, the model provides estimates of country-level socioeconomic resilience. Because floods disproportionally affect poor people, each $1 of global flood asset loss is equivalent to a $1.6 reduction in the affected country's national income, on average. The model also assesses and ranks policy levers to reduce flood losses in each country. It shows that considering asset losses is insufficient to assess disaster risk management policies. The same reduction in asset losses results in different welfare gains depending on who benefits. And some policies, such as adaptive social protection, do not reduce asset losses, but still reduce welfare losses. Asset and welfare losses can even move in opposite directions: increasing by one percentage point the share of income of the bottom 20 percent in the 90 countries would increase asset losses by 0.6 percent, since more wealth would be at risk. But it would also reduce the impact of income losses on wellbeing, and ultimately reduce welfare losses by 3.4 percent.
  • Publication
    An Exploration of the Link between Development, Economic Growth, and Natural Risk
    (World Bank, Washington, DC, 2013-05-05) Hallegatte, Stéphane
    This paper investigates the link between development, economic growth, and the economic losses from natural disasters in a normative analytical framework with an illustration on hurricane flood risks in New Orleans. It concludes that under broad conditions it is optimal for (1) the probability of disaster occurrence to decrease with income; (2) the capital at risk—and thus the economic losses in case of disaster — to increase faster than economic growth; and (3) the average annual losses to grow faster than income at low levels of development and slower than income at high levels of development. Increasing risk-taking reinforces economic growth; improving protections transfers risks from frequent low-intensity events to rare high-impact events.
  • Publication
    The Indirect Cost of Natural Disasters and an Economic Definition of Macroeconomic Resilience
    (World Bank, Washington, DC, 2015-07) Hallegatte, Stephane
    The welfare impact of a disaster does not depend only on the physical characteristics of the event or its direct impacts in terms of lost lives and assets. Depending on the ability of the economy to cope, recover, and reconstruct, the reconstruction will be more or less difficult, and the welfare effects smaller or larger. This ability, which can be referred to as the macroeconomic resilience of the economy to natural disasters, is an important parameter to estimate the overall vulnerability of a population. Here, resilience is decomposed into two components: instantaneous resilience, which is the ability to limit the magnitude of the immediate loss of income for a given amount of capital losses, and dynamic resilience, which is the ability to reconstruct and recover quickly. The paper proposes a rule of thumb to estimate macroeconomic resilience, based on the interest rate (a higher interest rate decreases resilience and increases welfare losses), the reconstruction duration (a longer reconstruction duration increases welfare losses), and a “ripple-effect” factor that increases or decreases immediate losses (negative if enough idle resources are available to cope; positive if cross-sector and supply-chain issues impair the production of non-affected capital). An optimal risk management strategy is very likely to include measures to reduce direct impacts (disaster risk reduction actions) and measures to reduce indirect impacts (resilience building actions).
  • Publication
    The Impacts of Climate Change on Poverty in 2030 and the Potential from Rapid, Inclusive, and Climate-Informed Development
    (World Bank, Washington, DC, 2015-11) Rozenberg, Julie; Hallegatte, Stephane
    The impacts of climate change on poverty depend on the magnitude of climate change, but also on demographic and socioeconomic trends. An analysis of hundreds of baseline scenarios for future economic development in the absence of climate change in 92 countries shows that the drivers of poverty eradication differ across countries. Two representative scenarios are selected from these hundreds. One scenario is optimistic regarding poverty and is labeled “prosperity;” the other scenario is pessimistic and labeled “poverty.” Results from sector analyses of climate change impacts—in agriculture, health, and natural disasters—are introduced in the two scenarios. By 2030, climate change is found to have a significant impact on poverty, especially through higher food prices and reduction of agricultural production in Africa and South Asia, and through health in all regions. But the magnitude of these impacts depends on development choices. In the prosperity scenario with rapid, inclusive, and climate-informed development, climate change increases poverty by between 3 million and 16 million in 2030. The increase in poverty reaches between 35 million and 122 million if development is delayed and less inclusive (the poverty scenario).
  • Publication
    Should Marginal Abatement Costs Differ Across Sectors? The Effect of Low-Carbon Capital Accumulation
    (World Bank, Washington, DC, 2013-04) Vogt-Schilb, Adrien; Hallegatte, Stephane
    The optimal timing, sectoral distribution, and cost of greenhouse gas emission reductions is different when abatement is obtained though abatement expenditures chosen along an abatement cost curve, or through investment in low-carbon capital. In the latter framework, optimal investment costs differ in each sector: they are equal to the value of avoided carbon emissions, minus the value of the forgone option to invest later. It is therefore misleading to assess the cost-efficiency of investments in low-carbon capital by comparing levelized abatement costs, that is, efforts measured as the ratio of investment costs to discounted abatement. The equimarginal principle applies to an accounting value: the Marginal Implicit Rental Cost of the Capital (MIRCC) used to abate. Two apparently opposite views are reconciled. On the one hand, higher efforts are justified in sectors that will take longer to decarbonize, such as urban planning; on the other hand, the MIRCC should be equal to the carbon price at each point in time and in all sectors. Equalizing the MIRCC in each sector to the social cost of carbon is a necessary condition to reach the optimal pathway, but it is not a sufficient condition. Decentralized optimal investment decisions at the sector level require not only the information contained in the carbon price signal, but also knowledge of the date when the sector reaches its full abatement potential.
  • Publication
    Transition to Clean Capital, Irreversible Investment and Stranded Assets
    (World Bank, Washington, DC, 2014-05) Rozenberg, Julie; Vogt-Schilb, Adrien; Hallegatte, Stephane
    This paper uses a Ramsey model with two types of capital to analyze the optimal transition to clean capital when polluting investment is irreversible. The cost of climate mitigation decomposes as a technical cost of using clean instead of polluting capital and a transition cost from the irreversibility of pre-existing polluting capital. With a carbon price, the transition cost can be limited by underutilizing polluting capital, at the expense of a loss in the value of polluting assets (stranded assets) and a drop in income. In contrast, policy instruments that focus on redirecting investments -- such as feebates or environmental standards -- prevent underutilization of existing capital, avoid stranded assets, and reduce short-term losses; but they reduce emissions more slowly and increase the intertemporal cost of the transition. The paper investigates inter- and intra-generational distributional impacts and the political acceptability of climate change mitigation policy instruments.