Poor countries may lose 10 times more people to heat-related deaths than wealthy ones as global temperatures continue rising, according to an analysis by Climate Impact Lab published in . The research was designed to help cities and communities understand and respond to the specific dangers they face from rising temperatures, translating global warming projections into regional mortality estimates that connect abstract climate data to concrete public health outcomes. The findings arrive as a record-breaking heat wave grips much of the United States and as global atmospheric CO2 concentrations, measured at 429.35 parts per million at the Mauna Loa Observatory as of , continue climbing from the record high of 430 ppm reached in June 2025.
The central finding is not surprising to climate scientists who study heat mortality, but the scale of regional disparity it projects is striking. Countries in sub-Saharan Africa, South Asia, and parts of Latin America face mortality increases that could rival the current death toll from the most prevalent infectious diseases in those regions. Countries in northern Europe and North America face significant but far smaller increases. The relationship between national wealth and vulnerability to heat death is not incidental: it reflects differences in cooling infrastructure, healthcare access, labor conditions, and urban planning that are themselves products of historical economic development.
The Numbers by Region
Climate Impact Lab's projections translate temperature increase scenarios into regional mortality rates, benchmarked against familiar disease statistics to make the numbers legible. By 2050, under scenarios consistent with current emissions trajectories, the regional disparities are severe. Niger, Burkina Faso, and other countries in Africa's Sahel region could see 60 or more additional heat-related deaths per 100,000 people per year. That rate is higher than the current fatality rate from malaria across Africa. Djibouti, in the Horn of Africa, could experience a rise in heat mortality comparable to its current death rate from HIV/AIDS, which stands at approximately 55 deaths per 100,000 people. In southeastern Bolivia, the projected increase of roughly 30 additional deaths per 100,000 matches the current mortality rate from diabetes in that region.
"I continue to be shaken by the inequality of climate change. The extra deaths are all going to occur in places that contributed very little to greenhouse gas emissions that are warming the atmosphere."
Michael Greenstone, Economist and Co-Director, Climate Impact Lab, University of Chicago
| Region | Projected Additional Deaths/100K/Year by 2050 | Comparable Disease Benchmark |
|---|---|---|
| Niger, Burkina Faso, Sahel | 60+ | Higher than malaria fatality rate in Africa |
| Djibouti | ~55 | Comparable to HIV/AIDS rate in Djibouti |
| Southeastern Bolivia | ~30 | Similar to current diabetes mortality rate |
| South and Southeast Asia | High (varies) | Elevated above regional infectious disease rates |
| Northern Europe | Low to moderate | Significantly below regional disease benchmarks |
| United States / Canada | Low to moderate | Elevated in southern regions, lower in north |
Why Wealth Determines Survival
The gap between rich-country and poor-country outcomes is not primarily a function of geography or even temperature exposure. Countries at similar latitudes and with similar projected temperature increases show very different mortality projections depending on their income levels. The mechanism is infrastructure: wealthy countries have near-universal access to air conditioning, reliable electricity grids that keep it running during heat emergencies, healthcare systems that can treat heat stroke and heat exhaustion, and building standards that reduce the heat burden in residential spaces. Labor regulations in wealthy countries also generally allow workers to stop working outdoors when conditions become dangerous.
In many of the countries facing the worst projected outcomes, none of those conditions reliably apply. Agricultural workers and outdoor laborers who cannot afford to stop working face the full physiological burden of extreme heat without protection. Informal settlements and urban environments without tree cover or green space reach temperatures substantially higher than surrounding rural areas. Healthcare infrastructure that might identify and treat heat illness early is limited or absent. Air conditioning is either unaffordable, dependent on electricity supplies that are unreliable, or both.
Michael Greenstone, an economist at the University of Chicago who co-directs Climate Impact Lab and co-authored the report, summarized the moral dimension plainly: the deaths projected for the most vulnerable regions will overwhelmingly occur in places that have contributed little to the greenhouse gas emissions driving global warming. The Sahel and Horn of Africa produce a tiny fraction of global carbon emissions. The United States, Europe, China, and other wealthy industrialized economies account for the great majority of historical emissions. The distribution of harm is, by any measure, inverse to the distribution of responsibility.
The Current Warming Context
Climate Impact Lab's analysis lands in a specific atmospheric moment. The global average temperature in 2024 breached the 1.5 degrees Celsius warming threshold above pre-industrial levels, registering at 1.55 C according to the EU's Copernicus Climate Change Service. That figure represents the upper limit the Paris Agreement aimed to stay below to avoid the worst consequences of climate change. In 2023, the global average was 1.48 C. The last 11 years have been the warmest on record, a streak documented by the World Meteorological Organization in its annual climate report published earlier in 2026.
CO2 at 429.35 ppm, as measured at Mauna Loa in early March 2026, reflects a steady rise from under 320 ppm in 1960 and well below 280 ppm in the pre-industrial period. The rate of increase has itself been accelerating as economic activity and fossil fuel use have continued growing in much of the world. The UNEP's 2025 Emissions Gap Report concluded that even if every country met its current emissions reduction commitments, global temperatures could still rise by 2.3 to 2.5 degrees Celsius this century.
- 2024 global average temperature: 1.55 C above pre-industrial baseline (Copernicus)
- 2025 was the third warmest year on record after 2024 and 2023
- Atmospheric CO2 as of March 5, 2026: 429.35 ppm (NOAA Mauna Loa Observatory)
- UNEP projects 2.3 to 2.5 C rise this century even if all current commitments are met
- Poor countries projected to face 10x more heat deaths than rich ones by 2050 (Climate Impact Lab)
What the Research Is Designed to Do
Climate Impact Lab describes its analysis as designed to help cities and communities understand and respond to the specific dangers they face. That framing reflects a shift in how some climate research is positioned: not as general documentation of how bad things will become, but as actionable inputs for planning decisions. A city in the Sahel that understands its projected mortality increase can make a case for cooling infrastructure investment, adjust building codes, or design emergency response protocols specific to extreme heat events.
Whether that information translates into action depends on resources that many of the most vulnerable communities do not have. Building cooling infrastructure in a country that cannot maintain reliable electricity requires different interventions than deploying air conditioning in a wealthy suburb. Heat-resistant urban design, improved access to shade and water, changes in agricultural labor practices, and early warning systems for heat emergencies are all feasible at modest cost relative to the mortality they can prevent. But they require planning capacity, institutional follow-through, and funding sources that are not equitably distributed.
The research also arrives in a political environment where the United States, the world's largest historical emitter, is actively rolling back its own climate-related scientific infrastructure. The systematic removal of federal climate data and programs that occurred over the past year limits the capacity of US institutions to contribute to exactly the kind of regional mortality analysis that Climate Impact Lab is producing. The connection between data availability, research capacity, and policy response is direct: without reliable, publicly accessible climate and health data, the planning that could reduce the worst outcomes becomes harder to do. The global picture painted by Climate Impact Lab's report, set against the accelerating energy imbalance documented by the World Meteorological Organization, suggests the gap between the countries generating the problem and the countries bearing the worst consequences will continue to widen unless the distribution of both emissions reduction and adaptation investment changes substantially.
