Calculating the health impacts of climate change is a complex equation
Deadlier than COVID and even cancer? If the world does not take swift action to reduce carbon emissions, calculating the impact of global warming on health is a challenge for researchers who are faced with the phenomenon of “threat multipliers”, reported AFP.
The equation is too complicated, experts say. It must combine the many health consequences of global warming, from immediate dangers such as rising temperatures and extreme weather events, to long-term food and water shortages, through air pollution and disease.
The World Health Organization (WHO), which sees climate change as the biggest threat to human health, has called for it to be put at the center of negotiations at the COP27 climate conference.
Faced with global warming, humanity must “cooperate or perish,” UN Secretary-General Antonio Guterres warned Monday at the opening of a summit in Egypt.
Between 2030 and 2050, the WHO expects climate change to lead to nearly 250,000 additional deaths per year caused by “malnutrition, malaria, diarrhoea, heat stress”.
That estimate is believed to be much lower than the actual figure, especially since it only includes some factors, says Jess Bigley of the non-governmental organization Global Climate and Health Alliance, for which “climate change is multiplying threats”.
Nearly 70 percent of the world’s deaths are due to diseases that global warming could worsen, according to a report released this year by the UN’s climate panel.
Warmer temperatures also push virus-carrying animals such as mosquitoes into new areas, increasing the spread of existing diseases as well as the risk of new ones spreading.
In the past decade, the possibility of malaria transmission has increased by almost a third (32.1 percent) in some parts of the Americas and by 14 percent in Africa compared to the period 1951-1960.
The risk of dengue transmission increased by 12 percent worldwide during the same period, according to the Lancet Countdown, an annual survey of experts from 51 institutions, including the WHO and the World Meteorological Organization (WMO).
Rising temperatures also favor the spread of disease-causing bacteria in the water.
Another major threat is food shortages. According to the annual survey, nearly 100 million more people were in a situation of severe food insecurity in 2020 compared to 1981-2010.
The Lancet Countdown also notes that extreme drought has increased by almost a third over the past 50 years, putting hundreds of millions of people at risk of water shortages.
The same study showed that heat-related deaths jumped 68 percent between 2017 and 2021 compared to the period 2000-2004.
Air pollution contributed to 3.3 million deaths in 2020, including 1.2 million directly linked to fossil fuel emissions, according to the Lancet Countdown.
In the future, global warming could lead to more cancer deaths in some parts of the world, especially the poorest, according to a new data platform launched by the United Nations Development Program and the Climate Impact Lab.
In the worst-case scenario, if fossil fuel emissions are not reduced quickly, climate change could increase global mortality by 53 deaths per 100,000 people by 2100. This is about twice the current rate of cancer deaths of the lung.
For the current world population, this would mean 4.2 million additional deaths per year, more than the official toll of COVID-19 in 2021.
According to Hannah Hess of the Climate Impact Lab, these estimates are likely underestimates because they do not include certain threats such as vector-borne diseases.