A new global study has revealed a stark and growing inequality in the impacts of climate change, warning that low- and middle-income countries could account for more than 90 percent of heat-related deaths in the coming decades.
The report, released by the Climate Impact Lab, finds that rising global temperatures are projected to significantly increase mortality rates worldwide—with the burden falling disproportionately on poorer nations that are least responsible for greenhouse gas emissions.
According to the study, by 2050, ten times more people are expected to die from heat in poorer countries than in wealthier ones, highlighting what researchers describe as one of the most troubling dimensions of the climate crisis.
“This report uncovers one of climate change’s cruelest ironies,” said Michael Greenstone, co-founder of the Climate Impact Lab and director of the Energy Policy Institute at the University of Chicago.
“It is projected to kill millions in countries that have contributed the least to the problem, while those countries are also less equipped to respond to the risks,” he added.
The findings point to regions across Sub-Saharan Africa and South Asia as being among the most vulnerable, due to a combination of higher baseline temperatures and limited adaptive capacity.
For instance, the study projects that Burkina Faso could experience twice as many heat-related deaths as Kuwait, despite having similar climate conditions—largely due to differences in income levels and access to adaptive infrastructure.
At the city level, the disparity is even more pronounced. More than 15 times as many people are projected to die from extreme heat in Faisalabad compared to Phoenix, a wealthy urban center in the United States with greater access to cooling systems and healthcare infrastructure.
The report emphasizes that the scale of future climate-related mortality will depend not only on rising temperatures, but also on how governments and communities invest in adaptation measures.
These include:
- Access to air conditioning
- Development of cooling centres
- Urban planning for heat resilience
- Strengthened public health systems
Researchers note that targeted investments in these areas could significantly reduce the number of premature deaths linked to extreme heat.
“Correctly choosing where to invest limited resources could have a massive impact on who lives and who dies,” said Tamma Carleton, a lead researcher with the Climate Impact Lab and professor at the University of California Berkeley.
The study is based on one of the most comprehensive global datasets on temperature-related mortality, combining highly localized climate and health data to generate detailed projections.
It forms part of a broader “Adaptation Roadmap” initiative by the Climate Impact Lab, aimed at identifying where climate investments can deliver the greatest life-saving benefits.
The initiative seeks to move beyond risk assessment to provide practical, data-driven guidance for governments, investors, and development partners.
Experts say the findings reinforce the urgent need to place climate adaptation at the center of global climate policy, alongside efforts to reduce emissions.
As climate risks intensify, the report argues that failure to invest in adaptation—particularly in vulnerable regions—could result in millions of preventable deaths.
“Effective climate adaptation depends on knowing where action is most needed,” Greenstone said. “This research provides a roadmap to help direct those efforts where they can have the greatest impact.”
For African countries already facing rising temperatures, rapid urbanisation, and limited infrastructure, the implications are significant. Without targeted investment in heat resilience, healthcare, and urban planning, the continent could face some of the most severe human impacts of climate change globally.
