9 Health
9.1 Death
Lancet
Heat-related deaths of people older than 65 years increased by 85% compared with 1990– 2000.
Lancet (2023) The 2023 report of the Lancet Countdown on health and climate change
9.1.1 Croatia Europe’s Heat Death Hot Spot
Niranjan
The small Croatian city of Osijek is Europe’s heat death hotspot. In the past two decades, hot weather has proved deadlier there than in any other city in Europe, a study in the Lancet medical journal found. The researchers modelled temperature and mortality data from the 854 biggest cities in Europe and found Croatians were most likely to died from the heat.
Hot weather killed 70,000 people across the continent last summer and the death toll in 2023, the hottest year on record, may prove higher still. Doctors say the human cost of a heatwave hinges not just on climatic factors but also how vulnerable people are and how well they respond.
Osijek, a city of 100,000 people near Croatia’s border with Serbia, does not stand out as a city that should suffer from hellish heat. The agricultural Slavonia region in which it sits is hotter than the capital, Zagreb, but not as hot as coastal Dalmatia.
Adding to the mystery, Osijek is home to nature that should keep it cool. The city sits on the banks of the Drava River, which flows into the Danube 12 miles downstream, and looks out on to Kopački Rit, one of Europe’s biggest wetlands. Urban planners built parks in the city when it was under the rule of the Austro-Hungarian empire.
The conundrum is not just a problem for Croatia. The hunt for answers in Osijek and in Zagreb, where hot weather has proved only slightly less deadly, could help heat-stricken cities across Europe adapt as the climate grows less hospitable to humans.
The bodies of water that surround Osijek are slow-moving or still, which makes the air humid. Lots of water in the air means fewer beads of sweat evaporate off the skin and draw heat from the body. Scientists have warned that “wet-bulb” temperatures that account for heat and humidity are in some parts of the world nearing the limits of what the human body can take.
The Lancet study did not factor humidity into its models but recent research suggests it does not change much, said Pierre Masselot, of the London School of Hygiene & Tropical Medicine, the lead author of the study. “From an epidemiological point of view, humidity doesn’t seem to play a big role in mortality directly, although there’s no denying that there is a response.”
Doctors call heat a silent killer because only a fraction of the deaths it triggers are logged as such. While some people die from heatstroke on farms or building sites, with death certificates that name heat as the cause, many more die in hospital beds and retirement homes as they fight off heart and lung disease. Hot days push weak bodies into overdrive and warm nights prevent them from recovering. The result is a spike in excess mortality that shows up only in the statistics.
A study of Vietnam war survivors in 2020 found exposure to war was associated with heart disease later in life – particularly in women, who for a mix of reasons die at higher rates than men in heatwaves. In Osijek, where some buildings are pockmarked from shells that fell during Croatia’s war of independence with Yugoslavia in 1991, residents may be carrying hidden scars that leave them vulnerable to heat.
Food may be another factor. Croatia has the highest share of people who are overweight or obese in Europe. On its coast, people favour a Mediterranean diet of fish, vegetables and wine over meat, potatoes and beer. But Osijek and other Slavonian cities boast a fatty cuisine closer to that of central Europe.
Osijek had moved in the wrong direction. Driving down a road lined with stumpy trees and two-storey houses that towered over them, he said that two decades ago the local government had replaced the tall trees in several districts with short ones that provided little shade. Nobody had thought about the heat to come.
Niranjan (2024) ‘It’s full of green areas’: mystery of Europe’s heat death hotspot
9.2 Amazonas degradation sourcing pandemics
Romano
Home to the greatest biodiversity on the planet, the Amazon is also a ticking time bomb for the emergence or resurgence of diseases with pandemic potential. This is because environmental degradation and altered landscapes are important factors in this process, which are exacerbated during periods of extreme drought, such as the one now affecting the region.
In the Amazon in particular, the paving of the BR-319 highway, linking Porto Velho to Manaus, is a significant source of concern. Conservative estimates predict that deforestation around the road will triple in the next 25 years, mainly due to land speculation. This is made worse by the fact that 90% of the area directly affected consists of untouched forest.
And deforestation is not a static situation, but dynamic and unpredictable, resulting in the fragmentation of forests, increasing the risk of fires and reducing the biodiversity of the affected areas. The association between human action in the Amazon, climate change, disorganised migration and precarious social development creates a favourable environment for the emergence and resurgence of diseases, it has been shown. Known diseases…
This process can happen in different ways. The degradation of conserved areas and the diversion of rivers and extreme drought, can, for example, lead to water and food shortages. And this poses a direct threat of malnutrition, affecting the health of local populations and leaving them more vulnerable to known diseases.
Lack of clean water and poor hygiene in drought conditions also increase the risk of diseases transmitted by contaminated water and food, such as cholera and hepatitis, and viruses that cause severe diarrhoea, such as rotavirus. Making matters worse, the incidence of diseases associated with poor fish preservation, such as rhabdomyolysis (black urine disease) - which is not infectious - also rises during extreme droughts.
Global warming is also a critical factor in this process, allowing an increased presence of mosquitoes that transmit diseases such as malaria and dengue fever. An increase of just a few degrees in the planet’s average temperature can allow them to colonise areas that were previously inaccessible. In regions where they are present, environmental degradation can increase or decrease rainfall periods, favouring flooding and the maintenance of standing water, and facilitating their proliferation.
Not surprisingly, vector-borne diseases are classic cases of outbreaks due to environmental imbalance. The recent humanitarian crisis of the Yanomami, a tragedy caused by illegal mining, land grabbing and lack of access to health services, is a case in point. In addition to the contamination of water and the environment by mercury, mining activity has created a favourable environment for the reproduction and spread of mosquito species of the genus Anopheles, the transmitter of the protozoan that causes malaria.
This is because digging ravines to extract gold and minerals creates pools of water that act as artificial breeding sites. In addition, mining activity increases the human population in these remote regions, which facilitates the spread of malaria. In numerical terms, while between 2008-2012 around 20% of malaria cases occurred in Yanomami territory, between 2018-2022 almost 50% of cases affected this population. … and new diseases
Zoonotic diseases (transmitted from animals to people) present an even greater potential problem. While some pathogens (disease-causing agents such as viruses and bacteria) are capable of infecting one or a few host species, others are more generalised and can, if there is contact and opportunity, infect a wide variety of animals.
This type of “jump” from one host to another occurs constantly among animals in their natural habitat, for example from bats to non-human primates, small rodents and other mammals. However, there is usually a balance in the circulation of these agents.
But when habitats are destroyed, for whatever reason (human or otherwise), local species migrate to more conserved areas in search of food and shelter. And this can lead them to areas close to human settlements – and facilitate contact between wild animals and people. Impossible to predict, but possible to monitor
Unfortunately, preventing zoonoses is not an easy task – is no effective method that can predict what the next emerging disease will be, or from where it will emerge.
But it is possible to keep an eye on it. To do this, we monitor the circulation of resistant viruses and bacteria in samples of water, animals and vectors, as well as humans. Animals such as bats, rodents and primates are subjected to next-generation sequencing technologies for early detection of circulating agents that could pose a threat to human health.
And yet it’s not enough. To be effective, surveillance must be constant and cover local and national levels. Although Brazil has the capacity and basic technical infrastructure for this, few actions are actually implemented. In addition to surveillance, we need investments in faster and more accurate diagnostic methods that can help contain the spread of potential new diseases with pandemic potential.