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What are the observed health impacts of climate change so far? September 19, 2022

I read almost every issue of American Family Physician, a peer-reviewed family medicine journal that I use along with other medical journals like the Journal of American Medical Association, Consultant, and the Journal of Family Practice to keep up with the latest practice guidelines in family medicine. I usually find the content relevant for staying up to date in my profession as a family doctor. While I don’t agree with everything that is included, I do agree with most, and find these journals to be insightful and educational. 

I recently read through a copy of the  November 2021 edition of American Family Physician and noted an article entitled, “Climate Change and the Local Environment: Communicating with Your Patients about Health Impacts”. I have been keenly interested for years regarding the health impacts of climate change, and have performed extensive research on this topic. After reading it, I decided to write a letter to the Editor. I did so, but the editor rejected it for publication. I am submitting the letter in its entirety here. The discussion around health impacts from climate change is a serious issue. We should all take it very seriously. 


To the Editor:

I read Curbside Consult by Doctors Wellbery, Lewandowsky, and Holder regarding “Climate Change and the Local Environment: Communicating with Your Patients about Health Impacts” in American Family Physician November 2021 with great interest. The authors state, “The effects of climate change on individual and entire population health are well established.” However, the two studies they cite to support their position (Frumkin, et. al, and the 2020 report of The Lancet Countdown on health and climate change) unfortunately do not provide objective, observational global health trend outcome data. Instead, these studies rely on subjective modeling and projection data. Neither approach has been externally validated.

Looking at real-world observational data, we see that global fires with associated negative health outcomes have actually significantly decreased,[1] global human vulnerability to heat has decreased,[2] [3] global childhood stunting has decreased[4] and global deaths by all natural disasters[5] have significantly decreased over time. Global crop yields have mainly increased, and global malaria incidence is flat or down.[6]

If the authors want family physicians to support the idea that climate change is a “health emergency” and “the greatest public health threat of our century”, they need to provide real-world, observational evidence in peer-reviewed journals to back up these phenomenal claims. Modeling studies and consensus statements by definition in evidence-based literature do not constitute “well established” science. I implore American Family Physician to apply evidence-based research in all areas of health studies, including the area of health outcomes due to climate change.


Scott Hastings, D.O.

[1] Earl, N., & Simmonds, I. (2018). Spatial and temporal variability and trends in 2001–2016 global fire activity. Journal of Geophysical Research: Atmospheres, 123, 2524– 2536.

[2] Scott C Sheridan and Michael J Allen 2018 Environ. Res. Lett. 13 043001.

[3] Ana M. Vicedo-Cabrera, Francesco Sera, Yuming Guo, Yeonseung Chung, Katherine Arbuthnott, Shilu Tong, Aurelio Tobias, Eric Lavigne, Micheline de Sousa Zanotti Stagliorio Coelho, Paulo Hilario Nascimento Saldiva, Patrick G. Goodman, Ariana Zeka, Masahiro Hashizume, Yasushi Honda, Ho Kim, Martina S. Ragettli, Martin Röösli, Antonella Zanobetti, Joel Schwartz, Ben Armstrong, Antonio Gasparrini,

A multi-country analysis on potential adaptive mechanisms to cold and heat in a changing climate,

Environment International, Volume 111, 2018, Pages 239-246, ISSN 0160-4120.

[4] https://apps.who.int/iris/bitstream/handle/10665/331621/9789240003576-eng.pdf. Accessed 8/27/2022.

[5] Giuseppe Formetta, Luc Feyen, Empirical evidence of declining global vulnerability to climate-related hazards, Global Environmental Change, Volume 57, 2019, 101920, ISSN 0959-3780.

[6] Qiao Liu, MD, Wenzhan Jing, PhD Candidate, Liangyu Kang, MD, Jue Liu, Min Liu, Trends of the global, regional and national incidence of malaria in 204 countries from 1990 to 2019 and implications for malaria prevention, Journal of Travel Medicine, Volume 28, Issue 5, July 2021, taab046.

Please note these two things: 1. I have zero financial relationships with energy companies. 2. Hiding, covering up, or otherwise reducing exposure to scientifically valid information constitutes misinformation, regardless of the politics. I call on those who make publishing or ranking decisions to keep this in mind. When we say “the science is settled” I tend to get really nervous. When it comes to climate change and health impacts, the current available science seems to say the science is more settled toward “no effect” than anything. 

On almost every measure, I have found that historical trends regarding heat deaths, fire frequency, deaths caused by natural disasters, malnutrition deaths, and infectious disease deaths have all significantly declined over the decades or remain flat. This is an enormous problem for the climate science community that insists that climate change is creating the largest health threat of humankind. Really? Based on modelling studies and consensus statements? At what point are we able to call them out on this?  Why is it that these obvious findings are largely shut out of the scientific and medical communities? 

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