Climate change is advancing menacingly, posing a growing threat to humanity, as noted in a study. The research suggests that human-induced global warming and erratic rainfall could reduce the average human lifespan by approximately six months. This underscores the urgent need for global efforts to address and mitigate the consequences of global warming, aiming to protect both the environment and humanity.
Amit Roy from Shahjalal University of Science and Technology and The New School for Social Research, USA, used a composite climate change index. The findings indicate that the worst affected will be women and individuals in developing nations. The study is published in the open-access journal PLOS Climate.
The study’s outcome is particularly significant, as it establishes, for the first time, a link between climate change and life expectancy. We have already observed, through well-documented research, the impact of temperature and rainfall - two telltale signals of climate change. These factors contribute to a range of public health concerns, from the acute and direct, such as natural disasters like flooding and heat waves, to the indirect yet equally devastating, including respiratory and mental illnesses.
To elucidate the relationship between life expectancy and climate change, the author examined data on average temperature, rainfall, and life expectancy from 191 countries spanning the years 1940 to 2020. GDP per capita was used to control for drastic differences between countries.
In addition to measuring the isolated impacts of temperature and rainfall, the author designed a first-of-its-kind composite climate change index, combining these two variables to gauge the overarching severity of climate change. The findings of this study suggest that if the annual average temperature increases by 1 degree Celsius, life expectancy at birth will decline by 0.44 years. Moreover, the temperature rise will further negatively impact life expectancy by interacting with the rainfall cycle.
“If the composite climate change index - an index of the geometric mean of temperature and rainfall - increases by 10 points, life expectancy at birth will decline by 0.50 years. Furthermore, climate change will disproportionately reduce the life expectancy of females more than that of males,” said the author.
Beyond the results of this study, Dr Roy is hopeful that the composite climate change index will standardise the global conversation about climate change, become a usable metric for the nonscientific public, and encourage collaboration and even friendly competition among countries to combat the impacts of climate change. Mitigating greenhouse gas emissions and adapting to a changing environment are of particular importance, the author says.
To complement this large-scale approach, the author suggests localised future studies that consider specific severe weather events (e.g., wildfires, tsunamis, and floods), the impacts of which cannot be fully captured through analysing temperature and rainfall alone.
The disruption of our climate system, along with rising temperatures and abnormal rainfall, is brought about by associated natural calamities like extreme heatwaves, powerful storms, hurricanes, tropical cyclones, flooding, droughts, wildfires, and rising numbers of insect and vector-borne diseases. These events can have far-reaching and often devastating consequences for the economy, ecosystem, health, and human society. For instance, rising temperatures can result in more frequent and intense heatwaves, leading to heat-related illnesses and higher mortality.
The study also highlighted various threats that nations are already experiencing due to climate change, with serious implications for both humans and flora and fauna. For instance, the author points out that droughts can impact water availability for agriculture, industry, and households, leading to water scarcity, crop failures, food shortages, and a reduction in expected life spans. Flash floods and river floods can damage infrastructure, displace communities, and result in casualties.
Warmer ocean temperatures can fuel the development and intensification of tropical storms, leading to more powerful hurricanes and cyclones. These storms can bring widespread destruction to the lives and livelihoods of people. Rising temperatures, prolonged droughts, and changes in vegetation patterns can also create conditions conducive to wildfires. These fires can devastate forests, destroy homes, and have serious air quality and health implications, said the author.