Essay by Eric Worrall
But world leaders are giving less attention to climate health consequences in international debate.
Climate change is killing hundreds of thousands – a kidney specialist’s concerns
Published: November 4, 2026 3.42am AEDT
Peter Stenvinkel
Professor of Nephrology, Karolinska InstitutetThe evidence that climate change threatens human health has never been stronger. Yet a new report suggests that world leaders are giving less attention to its health consequences in international political debate.
The 2026 Lancet Countdown report estimates that heat was associated with 710,000 deaths worldwide in 2023, with around 71% attributable to human-caused climate change. Researchers calculated this by comparing estimated heat-related deaths at the temperatures actually experienced with those expected in a world without human-caused warming. The difference represents the additional deaths associated with climate change.
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Meanwhile, the proportion of countries whose leaders discussed the relationship between climate change and health during the United Nations General Debate fell from 66% in 2021 to 26% in 2025. The General Debate is the annual gathering at which world leaders address a broad range of international issues.
…As a kidney physician, I see particular reasons for concern. Chronic kidney disease affects hundreds of millions of people worldwide. The kidneys help filter waste from blood and maintain the body’s balance of water and salts, making them vulnerable when extreme heat disrupts that balance.
Recent research links hot temperatures with increased kidney-related illness. Heat stress and dehydration can contribute to acute kidney injury, particularly among people working in hot conditions and those with existing health problems. Whether repeated heat exposure accelerates chronic kidney disease across the wider population is less certain and remains an important research question.
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Read more: https://theconversation.com/climate-change-is-killing-hundreds-of-thousands-a-kidney-specialists-concerns-295393
For some reason the professor forgot to mention the impacts of cold weather on kidneys. From my favourite magic box;
can cold weather stress kidneys?
Yes, in a few ways, though for a healthy person ordinary cold weather isn’t harmful to the kidneys. The effects matter more for people who already have kidney disease, high blood pressure, or heart problems.
Cold-induced diuresis. When you’re cold, blood vessels in your skin and limbs constrict to conserve heat. That pushes more blood into your core, and your body reads this as having too much fluid. It reduces antidiuretic hormone (ADH) and releases more atrial natriuretic peptide, so your kidneys make more urine. That’s why you need to pee more often in the cold. The kidneys aren’t damaged by this, but it can leave you mildly dehydrated, especially since people also tend to feel less thirsty and drink less in cold weather.
Higher blood pressure. That same vasoconstriction raises blood pressure, and average blood pressure is measurably higher in winter. Sustained high blood pressure is one of the main drivers of kidney damage over time. It isn’t a big deal for one cold day, but it’s relevant for someone whose blood pressure is already poorly controlled.
Severe cold and hypothermia. This is where real acute stress happens. Blood flow to the kidneys drops, and the kidneys lose some of their ability to concentrate urine. In serious cases, muscle breakdown (rhabdomyolysis) and low blood pressure during rewarming can cause acute kidney injury. This is a medical-emergency scenario, not everyday chilliness.
Indirect winter factors. Winter also brings more flu and other infections, plus more use of anti-inflammatory painkillers like ibuprofen. Combined with dehydration, these are a common route to acute kidney injury in vulnerable people.
The practical takeaway is to drink enough even when you’re not thirsty, keep warm, and, if you have kidney disease or high blood pressure, monitor your blood pressure more closely in winter.
Read more: https://claude.ai/share/8f538982-6feb-4c32-9fff-4d5865bbd7d3
Cold weather deaths dominate warm weather deaths, even in warm countries like India, where cold weather deaths outnumber warm weather deaths by 7:1.
Studies have indicated the warmer weather associated with global warming since the mid 1800s has saved more lives than it has killed.
How can we see the quoted article as anything other than climate activism in a lab coat?
If the professor had argued the harm from global warming outweighs the gains from warmer winters, or argued studies indicating global warming are a net benefit are mistaken, and given reasons for this opinion, I might have disagreed, but I would have had respected his contribution to the debate.
But writing a one sided article which suggests global warming is a net negative in terms of human health, without making any attempt to mention mitigating factors such as the likely health benefits of warmer cold seasons, or that some studies suggest global warming is net beneficial in terms of seasonal deaths, in my opinion the article Professor Stenvinkel wrote is just propaganda, climate activism masquerading as science.
Is this what you are teaching your students Professor Peter Stenvinkel? Because failing to address or at least acknowledge contradictory evidence when trying to persuade the public that global warming is a health risk is not the kind of scientific conduct which I was taught as a student.
