Kip Hansen’s guest essay – June 30, 2022
Precious magazine Science brought this story from Latin America in Climate section:
Extreme temperatures in major Latin American cities could lead to nearly 1 million deaths
“A rise of 1°C could mean thousands more deaths on days that are too hot, according to a new study.” Rodrigo Perez Ortega
It leads to:
“In mid-January, the southern pole of South America was the worst heat wave in years. In Argentina, temperatures in more than 50 cities have risen above 40 °C [ 104°F ]more than 10°C [ 18°F ] warmer than typical average temperatures in cities like Buenos Aires. The scorching heat fueled wildfires, worsened droughts, affected agriculture and temporarily shut down Buenos Aires’ electricity supply. It also killed at least three people, although experts estimate the true number could be much higher.
With climate change, heat waves and cold spells is getting worse and take lives all over the world: about 5 million in the last 20 years, according to at least one study. In a new study published today in Natural Medicine, an international team of researchers estimated that nearly 900,000 deaths between 2002 and 2015 could be attributed to extreme temperatures in major Latin American cities alone. This is the most detailed estimate in Latin America, and the first for several cities. “
There is a study! An actual study published on natural medicine authored by Josiah L. Kephart and eleven others. “City-level impact of extreme heat and mortality in Latin America” [ .pdf here ].
Let’s start with the summary and compare it with the introduction in Science.
“Climate change and urbanization are rapidly increasing human exposure to extreme environmental temperatures, but very few studies have examined temperatures and mortality in Latin America. We conducted a non-linear, lagged, longitudinal analysis of daily ambient temperature and mortality in 326 Latin American cities from 2002 to 2015. We observed saw 15,431,532 deaths out of ≈2.9 billion years of risk. The over-fatal mortality rate was 0.67% (95% CI 0.58–0.74%) for heat-related deaths and 5.09% (95% CI 4 4). .64–5.47%) for cold deaths. The relative risk of death was 1,057 (95% CI 1,046–1.067%) per 1°C of higher temperature during extreme heat and 1,034 (95% CI 1,028–1.040%) per 1°C of lower temperature during extreme heat. very cold. In Latin American cities, a significant proportion of deaths are due to suboptimal ambient temperatures. The marginally increased observed hot temperature was associated with a rapidly increased risk of death. These risks were strongest in older adults and cardiovascular and respiratory mortality. “
One of the interesting things we see right away is the use of Bulk: 15,431,532 deaths, 2.9 billion years of risk. Well, they had a huge population over a very large area (1.5 continents) for 13 years, of which 15.4 million people died. But what is the result?
The excess mortality out of total mortality was 0.67% (95% confidence interval (CI) 0.58–0.74%) for heat-death related
The mortality overtotal mortality rate was 5.09% (95% CI 4.64-5.47%) for cold-death related
Conclusion: The excess mortality for cold-related deaths is 7.5 times higher than heat-related deaths.
And for relative risk (RR) that varies every 1°C change in highest/lowest temperature?
The relative risk of death was 1,057 (95% CI 1,046–1.067%) per 1°C of higher temperature during extreme heat and 1,034 (95% CI 1,028–1.040%) per 1°C of lower temperature during extreme heat. very cold.
Conclusion: While research makes a big deal about the differences in these two RRs, with a difference of only 0.023 – they are medically scientific, generally considered identical.
However, there is no reason to believe that this slight difference is not really. It can only show that the human body has different limited responses to small changes in the highest and lowest temperatures when averaged over a sufficiently large population.
Finally in this article, the authors try to warm up the villain despite the much higher risk of dying from the cold:
“Overall, The significantly higher mortality rate was due to the ambient being colder than the ambient heat, corroborating findings from similar analyzes in other environments. A 2021 analysis by Zhao et al. temperature-mortality associations estimated at 750 sites from 43 countries (including 66 sites in Latin America and the Caribbean), and extrapolated these estimates globally at a grid size of 0.5° × 0.5° (about 55 × 55 km2 at the equator) using meta-predictors. Zhao et al. The study reported global EDFs of 8.52% for cold and 0.91% for heat for all-ages, all-cause mortality. Here Global Cold EDF (8.52%) is almost double our estimated EDF for cold in Latin American cities (4.71%). “
And
“A 2017 study, including 32 sites in Mexico, Brazil and Chile, predicted that, under many climate change scenarios, the reduction in cold mortality in middle age would roughly counterbalance the increase in heat-related mortality, but by the end of the 20s – overwhelming heat-related mortality in the first century will cause a real substantial increase in heat-related mortality excessive level. “
[ Yes, that 2017 study finding uses RCP8.5. – kh ]
The Pérez Ortega study we are looking at today summarizes its findings in this table:
I have written about Cause of Death and its uses in studies more than once: Cause of death: A bait and Cause of death: Follow up. This study is not about death from heat or death from cold. It is about All Cause of Death with detailed information on major causes: Cardiovascular death, Respiratory death and Respiratory tract infection death with flare-ups for All ages and 65 years and older.
This study don’t even consider category of deaths due to extreme heat, heat or cold. There are causes of death due to excessive natural heat”2022 ICD-10-CM Diagnostic Code X30 Excessive natural heat exposure“and cold”2022 ICD-10-CM Diagnostic Code X31 Exposure to extreme cold naturally“. Quite simply, they don’t count people who die from heat or people who die from cold, not one at all.
The question the study poses and tries to answer is, “Do more people die than usual in Latin America when it’s unusually hot or when it’s unusually cold?”
What they don’t ask and don’t analyze are the most likely culprits for the problem itself: what are the poverty and levels of development in the cities studied? It is certain that poverty and underdevelopment – lack of electricity, lack of clean water, lack of adequate housing and lack of basic health and social support have even more impact on the number of “related deaths”. to temperature” more than the temperature itself.
USE THE ANSWER: While not surprising, this study confirms that more people die when ambient temperatures are at extremes (much higher or much lower than normal) for the locality. This study confirms that more people die in unusually cold weather than in unusually hot weather. This is a fact that affects older people (65+) more than younger people, and these excess deaths are the result of heart (cardiovascular) and respiratory (respiratory) problems. – but not directly from heat or cold.
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Author’s comment:
Readers here already know that cold kills more people than heat. This study shows this to be true again. The authors have made weak attempts – based not on their own research but on RCP8.5 speculative studies – to claim that this will cause more, not fewer, deaths will die in the future if the overall climate continues to warm.
As with all studies using All Cause death, no”cause“Found, just different vaguely related correlations. Any cause of death is one of the absolutely worst indicators used in such studies and used, quite frankly, because it’s easy. Cause of death is difficult, complicated, complicated, and the record of the ICD-10 code is unreliable (doctor rushes or doctor lies…). It is difficult to determine the true cause of individual deaths but it is easy to identify and count corpses.
We already know that more people, namely the elderly (us) die when it is very hot or very cold. We already know that more people die when it is very cold than when it is very hot. I do not believe that this study has found anything that makes humanity more knowledgeable or anything that can help policymakers in countries or regions come up with better policies to create a better world. In that sense, this study is “useless”.
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