This tool estimates how extreme heat affects economic output and mortality in cities around the world. It shows the likely impact on workers today and how those impacts could grow by 2050. It also helps users explore adaptation options and estimate their costs, benefits, and potential effects on the economy and mortality.
Extreme heat is affecting cities around the world, and the costs are rising. From increased mortality and illness to lost labor productivity, higher healthcare expenditures, and damage to infrastructure, communities pay a high price not only when temperatures soar but long after. For instance, heat can cause economic losses worth as much as 8% of city GDP in extreme years.
Yet, despite the scale of the impacts, many cities struggle to identify, prioritize, and finance effective adaptation measures. Too often, decision-makers lack the tools and evidence needed to understand who is most vulnerable, assess the costs of inaction, and compare the benefits of different interventions.
HERA’s first-of-its-kind tool and analysis help policymakers, practitioners, development partners, and other stakeholders understand the impacts of extreme heat and evaluate the case for adaptation.
Users can compare the costs and benefits of different adaptation measures to find those with the greatest returns, explore how heat affects mortality and economic output across 11,408 cities in 190 countries, and see how these impacts could evolve through 2050.
The tool provides both critical insights and practical frameworks for explaining how heat affects people and economies.
Heat is costing your city. See the return on investing in action
This tool calculates the costs of extreme heat and models what targeted interventions — from heat response plans to cool roofs, urban greening to income-loss insurance — would save in cities across the globe.
Choose a city, select, and adjust the intervention solutions, and explore the projected impacts on mortality, economic output, and return on investment through 2050.
The results in this tool have been estimated for a large set of cities built from global data. The results for each city have not been individually sense-checked, and users are advised to verify the numbers for their local area.
Who can use this tool
This tool is a resource developed by HERA and incorporates intellectual property contributed by Mode Economics. It is made freely available for use by practitioners, governments, public agencies, researchers, civil society organizations, development partners, private sector organizations, and other stakeholders interested in understanding and assessing the impacts of extreme heat.
Users are encouraged to apply the tool in ways that support evidence-based decision-making, planning, research, advocacy, and policy development. While outputs from the tool may be reported, adapted and reused, users should acknowledge HERA and Mode Economics as the original developers. Enquiries about the tool, its development, or terms of use should be sent to [email protected] .
How to use this tool
This tool is designed to help local policymakers, practitioners, and stakeholders build the business case for action. It produces indicative cost-benefit ratios for urban heat interventions, helping users understand the potential strategic value of different measures. Users can select their city and a preferred package of interventions to generate an indicative assessment of the value for money of each intervention and of the package as a whole, with impacts assumed to be additive. Users may also override a range of model inputs using their own city-level data; however, no responsibility is taken for results based on untested overridden inputs. More granular analysis, using detailed city-level estimates, is needed to build the business case for interventions, and this tool should not be used to support specific investment decisions.
Methodology & sources
A summary of the methodology is available here . The data used in the tool is publicly available and fully cited in the Methodology Note. The analysis and modelling were carried out by Mode Economics, and both the process and results were reviewed by public health and public policy experts.
For more information, please contact [email protected] .