Rising temperatures could shorten average human lifespan: study

“Climate change is putting the lives and health of billions of people at risk.” This strong statement begins a scientific study that suggests that global warming could shorten the average human lifespan by six months.

The study, shared in the ‘PLOS Climate journal', highlights that health problems could arise directly from temperature changes or natural disasters like floods and heatwaves. They could also occur indirectly, through environmental changes leading to respiratory or mental health issues, among others.

Amit Roy from Shahjalal University of Science and Technology and the New School of Social Research has explored how climate change affects life expectancy, a key measure often used to gauge a population’s health.

The study presents a new framework that connects the direct and indirect ways in which climate change affects health, an area that hasn’t been explored until now.

The researcher, Amit Roy, estimated the impact of climate change on life expectancy by analyzing data from 191 countries from 1940 to 2020. He used GDP per capita to account for differences between countries.

The findings suggest that if the average annual temperature rises by 1°C, life expectancy at birth will decrease by 0.44 years (about 161 days). Rising temperatures could further reduce life expectancy by affecting the precipitation cycle.

If the combined climate change index, which considers both temperature and precipitation, increases by 10 points, life expectancy at birth could decrease by 0.50 years, or about six months.

Women, more affected than men

The document states that climate change "disproportionately" reduces the life expectancy of women more than that of men. It further indicates that it also reduces the life expectancy of older people, children, and people in developing countries more significantly.

The author explains that to minimize health risks associated with climate change, we must "essentially" make efforts to reduce greenhouse gas emissions and adapt to changing conditions. Roy emphasizes that "countries need to take immediate actions to curb global temperature increases and protect their population's health from climate change."

"The researcher suggests future localized studies to complement this large-scale approach, which considers specific severe climate events (forest fires, tsunamis, floods...) whose impacts cannot be fully captured by analyzing temperature and precipitation alone."

Amit Roy highlights, "This study reveals that the global threat climate change poses to the well-being of billions of people underscores the urgent need to address it as a public health crisis.

The study states, "Adaptation measures and building resilience are crucial to protect human health in a warming world." It further suggests that we should implement public health measures, prepare for disasters, and improve health infrastructure to "increase resilience and reduce health risks associated with climate change."

Limitations of the study

Roy considers recognizing certain limitations associated with estimating the climate change index as "crucial", particularly when considering various scenarios involving fluctuations in both temperature and precipitation.

He explains that the traditional index might encounter limitations in distinguishing between the individual contributions of each factor when temperature increases, and precipitation decreases. The geometric mean might not entirely encapsulate the nuanced impacts of temperature increase and precipitation reduction in the general climate change scenario. This shortcoming could potentially result in underestimating the severity of certain climate changes."

"He notes that the geometric mean may not reflect the intricate dynamics at play in situations where the temperature decreases and precipitation increases. The index may not adequately convey the potential complexities that arise from different temperature and precipitation trends. This limitation might result in an oversimplified representation of the climate change scenario, overlooking the intricate interaction between these two factors."

He points out another case, "The geometric mean may not effectively distinguish the absence of extreme climatic variations, and the index may not adequately capture the subtleties associated with stable climatic conditions when both temperature and precipitation remain within normal ranges, which could lead to an excessive emphasis on the sensitivity of the index to extreme changes. This limitation highlights the need for additional indicators or adjustments when we evaluate climate stability scenarios."

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