Summary: New research indicates that climate change could shorten the average human lifespan by roughly six months. The study assessed temperature, rainfall, and life expectancy across 191 countries over the period 1940–2020, and introduced a composite climate change index to capture the combined effects of temperature and precipitation changes.
The author developed a novel composite index that blends temperature and rainfall variations to evaluate the broader public health consequences of a changing climate. Results suggest that each 1°C rise in global temperature is associated with an average decline in life expectancy of about five months, with women and populations in lower-income countries facing the greatest impacts.
Key Facts:
- A 1°C increase in global temperature corresponds to an estimated reduction in average life expectancy of roughly 0.44 years (about five months).
- A 10-point rise in the composite climate change index, which combines temperature and rainfall shifts, correlates with an approximate six-month drop in average life expectancy.
- The study finds that climate-driven reductions in life expectancy are not evenly distributed: women and people living in developing countries are disproportionately affected.
Source: PLOS
The cost of climate change may amount to about six months off the average human lifespan, according to a study published January 18, 2024, in the open-access journal PLOS Climate by Amit Roy of Shahjalal University of Science and Technology and The New School for Social Research.
Temperature and rainfall trends are two of the clearest signals of a changing climate, and both produce a wide range of health risks. These include immediate hazards such as heat waves, floods and storms, as well as longer-term and indirect effects including increased respiratory illnesses, vector-borne diseases, food insecurity, and worsening mental health. While many of these impacts are well-documented individually, linking climate variation directly to changes in life expectancy at the global scale has been challenging.
To clarify how long-term climate trends relate to population health, the researcher analyzed average temperature, rainfall, and life expectancy records for 191 countries spanning eight decades (1940–2020). The analysis used GDP per capita as a control variable to account for large socioeconomic differences between nations and their ability to respond to environmental stresses.
Beyond examining temperature and rainfall separately, the study introduces a first-of-its-kind composite climate change index that combines the two variables to better capture the overall severity of climate-driven environmental change. This index is intended to provide a single, interpretable measure that reflects how combined shifts in temperature and precipitation relate to human health outcomes.
Key findings show that, holding other factors constant, a 1°C rise in temperature is associated with an average reduction in life expectancy of approximately 0.44 years (about five months and one week). When the composite climate index increases by 10 points — reflecting more substantial combined temperature and rainfall changes — the expected decline in life expectancy is close to six months. Importantly, analysis indicates uneven impacts across demographic and socioeconomic groups, with women and residents of developing countries bearing a heavier burden.
The author argues that a standardized composite index could help make the global discussion about climate change more concrete and accessible. Such a metric might be useful for policymakers, public health officials, and the general public to compare trends, prioritize adaptation and mitigation efforts, and track progress over time.
Mitigation of greenhouse gas emissions and investment in adaptive strategies remain central recommendations. The study emphasizes the need for both emission reductions and policies that strengthen health systems, improve resilience to extreme weather, and reduce socioeconomic vulnerabilities that amplify climate risks.
The author also calls for complementary, localized research that examines specific extreme events — for example, wildfires, tsunamis, and floods — because those phenomena can produce severe localized impacts that are not fully captured by country-level temperature and rainfall averages. Such targeted studies can inform tailored interventions and emergency preparedness at regional and community levels.
As the study concludes, the global threat posed by climate change to health and longevity underscores the need to treat it as an urgent public health crisis. Coordinated mitigation and adaptation actions are essential to protect life expectancy and public health worldwide.
About this environmental neuroscience and longevity research news
Author: Charlotte Bhaskar
Source: PLOS
Contact: Charlotte Bhaskar – PLOS
Image: The image is credited to Neuroscience News
Original Research: Findings published in PLOS Climate