Global Warming: Why Extreme Heat Is A Growing Health Concern And What Can Be Done To Slow Climate Change 

A two-paper series on ‘Heat and Health’, published in The Lancet, has recommended ‘immediate and urgent’ globally coordinated efforts to mitigate climate change. 

New Delhi: With the passing years, the severity of global warming is increasing. Extreme heat, an increasingly common occurrence now, resulted in over 356,000 deaths in 2019 and the number is only likely to grow, according to a study published in The Lancet.  

“This is very concerning, particularly given the risk of exposure to high temperatures appears to have been increasing steadily for decades,” said Katrin Burkart from the University of Washington, co-author of the Global Burden of Disease modelling study.

Citing similar findings, a two-paper series on ‘Heat and Health’, also published in The Lancet, has stressed why “immediate and urgent” efforts, globally coordinated, are required to mitigate climate change challenges. 

These efforts, the authors suggest, will increase resilience to extreme heat so additional warming can be limited, permanent and substantial extreme heat worldwide can be avoided, and lives saved. 

When the ambient temperature is hot, people can suffer from associated heat stress, which leads to an increase in mortality and morbidity, and also higher chances of adverse pregnancy outcomes and mental health issues, the papers note. 

Extreme heat also reduces physical work capacity, and gives rise to occupational health problems. But if proper heat action plans are implemented, with people bringing changes in their behaviour or lifestyle, increased deaths and adverse health impacts can be avoided, the authors have said in the series. 

According to the papers, almost 50 per cent of the world population is affected by high heat episodes, and about 33 million workers, who are exposed to extreme heat, suffer from adverse health impacts. The people living in tropical regions are most vulnerable to climate change and extreme heat because their bodies will reach the heat tolerance limits sooner in the coming decades. 

Due to anthropogenic or human activities like vehicular transport and everyday activities, temperatures in urban areas have increased to a larger extent. More research work and risk mitigation activities should be conducted, so that heat related mortality and morbidity can be reduced, the authors noted.

What are the health risks associated with extreme heat?

According to the Global Burden of Disease modelling study published in The Lancet, and more deaths due to heat can occur in future because the global temperature is increasing annually at a rapid pace. 

Heat stroke occurs in a person when exposed to extreme heat stress, as a consequence of which the body is unable to regulate the internal temperature. Since heat stress leads to physiological strain, cardiorespiratory complications may occur. People belonging to older age groups and those living in isolation, who can't take proper care of themselves, are more prone to these adverse effects.

“Extremely hot days or heat waves that were experienced approximately every 20 years are now being seen more frequently and could even occur every year by the end of this century if current greenhouse gas emissions continue unabated. These rising temperatures combined with a larger and older population, mean that even more people will be at risk for heat-related health effects,” said Professor Kristie Ebi from the University of Washington, USA, co-lead author of the two-paper series.

She said the future will be quite different if greenhouse gas emissions can't be reduced, and action plans not developed.   

“Day-to-day summer activities – such as exercising and working outdoors – may change dramatically as increasing warming means people are at greater risk of exposure to intolerable heat far more often, particularly in tropical regions.”

What The Authors Suggest

Building infrastructure should be modified in such a way that it serves as a method of decreasing the negative impacts of extreme heat, including deaths, the authors said in their papers. 

According to them, the annual increase in temperature, as a result of global warming, should not exceed 1.5°C. Sustainable cooling mechanisms like planting more trees, constructing buildings with wall coatings that reflect heat, use of electric fans and other cooling devices must be implemented so people don’t suffer from physiological strain and their body temperature is regulated. 

The papers also highlighted how future dependence on air-conditioning will be unsustainable, and the communities most vulnerable to climate change cannot afford ACs anyways.

Ebi said there are two ways with which extreme heat can be counteracted — one of them is reduction of carbon emissions to reduce global warming, and the other is to identify prevention and response mechanisms.

“With more than half of the global population projected to be exposed to weeks of dangerous heat every year by the end of this century, we need to find ways to cool people effectively and sustainably.”

The authors of the two-paper series suggested that people can regulate their body temperatures and save themselves from the extreme heat by using cooling techniques like electric and misting fans, immersing feet in cold water, wearing wet clothing, and self-dousing with a water spray or sponge.

Other measures include taking short breaks from physical activity, staying well hydrated and improving ventilation.

Professor Ollie Jay of the University of Sydney, Australia, who is the co-lead author of the series, said more emphasis should be given on cooling the body instead of cooling the ambient air. 

“The effects extreme heat exposure can have on the body present a clear and growing global health issue. There are many sustainable and accessible options to reduce effects of heat exposure if we focus on innovations for cooling down the body instead of cooling down the air around us.” 

Buildings can be provided with better insulation and glazing, to keep them cool from within. If urban pollution is reduced, it can significantly reduce the extreme heat effects.

The authors also said heat action plans, including early warning systems and robust surveillance and monitoring, must include “evidence-based cooling strategies” to protect populations. 

According to Professor Jay, the fact that future generations will be at a higher risk of exposure due to extreme heat can't be changed, and hence, more research work must be conducted so that they can counteract the risks. 

“It is critical that the personal cooling strategies we recommend in heat-health action plans are based on scientific evidence. After all, having a plan is not enough; it must be the right plan.”

An editorial in The Lancet said it is mentioned that the root cause of extreme heat, which is greenhouse gas emissions, can't be counteracted through action plans. Hence, proper frameworks and policies must be formulated so that climate change can be mitigated in a sustainable manner.