Heat may kill more people than major diseases by 2100, says study

Heat may kill more people than major diseases by 2100, says study

NEW DELHI [Maha Media]: In a warmer world caused by climate change, the possibility of your dying from excessive heat will depend on which country you live in and whether you have the money to keep heat at bay with air conditioning and heat-resilient infrastructure, says a new global study linking temperature, income and mortality.

Poor countries that are closer to the equator will see more deaths from rising temperatures compared to richer countries that may also be experiencing similar temperatures by the end of this century, since the latter will have more money to spend on climate adaptation--such as air conditioning and heat resilient infrastructure--the study by Climate Impact Lab, a US-based consortium of climate scientists and experts, estimates.

Calling this the “starkest finding” of the study, Amir Jina, one of the co-authors, told IndiaSpend that countries that are poorer today will “not only get worse impacted as the world warms but they will also be less able to afford adaptation, leading to the projection of a lot of extra deaths”. In wealthy countries, people can pay to avoid the worst health impacts of climate change, stressed Jina, an assistant professor at the University of Chicago’s Harris School of Public Policy.

Even in a positive global scenario of growing country incomes and increased spending on adaptation, the study estimates excessive heat will cost 73 extra deaths per 100,000 people annually by the end of the century, if emissions of greenhouse gases rise unchecked. This is the current death rate for several major infectious diseases combined, including tuberculosis, HIV, malaria, dengue and yellow fever, data from the World Health Organization (WHO) show.

Countries like India that have large numbers of poor people and are also vulnerable to the worst effects of rising temperatures, will suffer the most. Independent Indian experts we spoke to said that the study is an important call to early action in reducing emissions, and provides a much-needed focus on mortality in the context of climate change, which has been under-estimated. However, its assumptions and findings need to be refined further in a country-specific context, they said.

Best and worst case scenarios

In a high emissions scenario, temperature increases could lead to 221 additional deaths per 100,000 every year globally by 2100, the study found. This is the same as the current annual death rate for all cardiovascular diseases, according to WHO data.

But the study also found that if the income of countries continues to grow and that leads them to spend more on climate adaptation, the world could achieve a two-thirds reduction of this figure.

First, the researchers estimated that if the future income growth of countries was accounted for, the mortality risk posed by a hotter world dropped by about 53% from 221 to 104 additional deaths per 100,000 annually by 2100.

Further, if this income growth also led to climate adaptation measures, the mortality risk would drop even further to 73 additional deaths per 100,000 annually by the end of the century, they found, reducing the 221 per 100,000 estimate by 67%.

But even in this best case scenario, the death rate would match the one for all major infectious diseases combined today, as we earlier stated.

‘Full mortality impact’

The climate adaptation required to achieve this 73 per 100,000 figure is costly and it would only be fair, the researchers felt, to include this cost while assessing the total impact of climate change in the future. According to their calculations, the cost of future climate adaptation can be converted to an equivalent of 12 deaths per 100,000. Calling this the “full mortality impact of climate change”, they estimated it to be 85 additional deaths per 100,000 by the end of the century, in a high-emissions scenario.

The numbers became less alarming as researchers calculated the full mortality impact of climate change of a moderate-emissions regime (leading to a predicted 2.4 degrees Celsius level of global warming by the end of the century) over a high-emissions one. The full mortality impact from climate change-induced heat would fall by 84% to 14 additional deaths per 100,000, they estimated.

This shows that “the benefits of greenhouse gas reductions are large”, the summary of the study published by Climate Impact Lab noted. Talking of the 2.4 degrees Celcius warming scenario, the summary said that “even mitigation efforts that fall short of the long-term targets of the Paris Agreement [limiting global warming to 2 degrees Celcius] would cut the projected mortality costs of warming.”

The global economic loss of additional heat-induced deaths, in a business-as-usual scenario of greenhouse gas emissions, will cost the world 3.2% of its economic output by 2100, the study found.

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