Climate change likely to increase mortality rate by six times: study

Excess temperature caused by climate change is not only fatal to nature but also to humans. A new study has found that climate change may increase the mortality rate by six times by the end of this century.

Experts at the University of North Carolina think ambient heat during the night will alter the normal physiology of sleep. This will eventually damage the immune system and increase the risk of heart disease, chronic illnesses, inflammation, and mental health problems.

Climate scientist Yuqiang Zhang said the risks of increasing temperature at night are frequently neglected. "However, we found that the occurrences of hot night excess (HNE) are projected to occur more rapidly than the daily mean temperature changes."

The study is published in The Lancet Planetary Health journal.

Findings suggest the restrictions from the Paris Climate Agreement may not do much to help the troubling impacts of climate change. The Agreement is aiming to limit global warming to 2°C compared to pre-industrial levels.

Researchers think the mortality rate can be significantly higher than estimated by the average daily temperature increase. The study has also found that the average intensity of hot nights will nearly double by 2090. It is likely to go from 20.4°C to 39.7°C across 28 cities in Asia. This will increase the risk of diseases that stems from a lack of normal sleep.

In the 2100s, the intensity and frequency of hot nights are expected to increase over 30-60%. The team assessed the mortality due to excess heat in 28 cities in China, South Korea, and Japan between 1980 and 2015 and applied it to two climate change modelling scenarios. Carbon-reduction scenarios adapted by the respective national governments were also factored in.

Scientists are also suggesting designing efficient ways to help people adapt to the increasing temperature. "Locally, heat during the night should be taken into account when designing the future heatwave warning system, especially for vulnerable populations and low-income communities who may not be able to afford the additional expense of air conditioning," said Zhang.

Haidong Kan, a professor at Fudan University in China, said their climate change models and studies highlight that in assessing the disease burden due to non-optimum temperature, governments and local policymakers should consider the extra health impacts of the disproportional intra-day temperature variations. The expert suggested better resource allocation and priority setting.