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My online debate regarding health effects of climate change Feb 3 2023

Recently, I asked to host a debate regarding the health effects of climate change with Dr. Steven Novella MD, neurologist and host of his own blog, Neurologica. He accepted my challenge, so I went first. I will post my side of the argument below. As of yet, he has not responded to my argument. We’ll see where this goes, but so far it’s not going anywhere. 

Here it is in it’s entirety: 

Hi Steven, first of all, I am tremendously grateful to you for taking time to engage with me on this very important topic. Thank you. 

I’d like to start by sharing just a few media articles I found that are now over 3 years old: 

New York Times: November 13, 2019 “Climate Change Poses Threats to Children’s Health Worldwide

ABC News Australia: November 5, 2019 “11,000 scientists declare climate emergency warning world faces catastrophic threat

CNN: November 12, 2019 “The climate crisis will profoundly affect the health of every child alive today,

Wired: November 13, 2019 “How the Climate Crisis Is Killing Us, in 9 Alarming Charts, A new report from over 100 experts paints a devastating picture of how climate change is already imperiling human health.”

We are both physicians, so I don’t want to leave out the American Medical Association statement on climate change

I think you get the point…We are daily inundated with a “climate emergency” just around the corner.  It also seems that all the experts (at least 97% anyway) are in some general agreement about the “devastating catastrophe” lurking somewhere out there. However, the official IPCC-5 report seems to be a whole lot less confident than the headlines mentioned above. 

My aim is to take exact verbiage from IPCC-5, then apply the most up to date scientific literature available to cross-check their stated claims. Since I’m a physician, I am specifically interested in health outcomes as a result of climate change. I am looking at global health trends (since this is a global phenomena), as well as trends in global natural events like floods, fires, and hurricanes as these obviously contribute to health outcomes.  It’s simple really, in our world of experts, nobody needs to be an expert at opening the newspaper the morning after the superbowl to see who won the game. In this case, the “newspaper” is going to be scientific research literature based on global observational trends from generally that was published in the past 6 years. What I will not include is modeling studies. That’s like trying to predict who is going to win the superbowl. I’m not interested in that.  Just real-world objective observations found on google scholar or pubmed. I’m only interested in who won the superbowl, not in some supposed “superbowl prediction expert”. 

Are you ready?

Claim: IPCC-5 Page 713 states, “Until mid-century climate change will act mainly by exacerbating health problems that already exist (very high confidence).”

Observation: Heart attack incidence rates in Norway have decreased and heart disease deaths in Peru both have decreased over time. Heart disease events in Norwegian RA patients have decreased over time. Heart disease hospitalization rates in England and Australia have decreased as well. 

Observation: Although heart disease incidence is increasing worldwide, it is actually decreasing after adjusting for age (just means we’re all living longer = more heart disease due to age). 

Observation: Diabetes complications have decreased over time

Observation: No difference in asthma burden over 25 years, and a significant decrease in asthma related deaths

Observation: While global colorectal cancer incidence is slightly increasing, we have no idea that any of it is because of climate change, especially due to the fact that gastric cancer incidence and mortality is decreasing, and other cancers are both increasing and decreasing, depending on which area of the world is being investigated. 

Observation: Global pneumonia mortality rates have decreased, in both adults and children

Where are the exacerbations of health problems? 

Now, you might say “Well, that’s because knowledge and advancements in technology have increased over time leading to these decreases in adverse outcomes.” And you would be correct. To which I would respond by telling you to re-read the IPCC-5 statement above. It says nothing about this obviously confounding variable. They are “very highly confident” that “until mid century, climate change will exacerbate health problems that already exist.” Period. 

Claim: “Existing diseases (e.g., food-borne infections) may extend their range into areas that are presently unaffected (high confidence).”

Observation: While existing diseases may be extending their geographic ranges, it is almost impossible to attribute this to climate change without including  globalization of trade routes. Infectious disease mortality rates may act as a surrogate, as existing diseases that are expanding to new areas should generally show increasing mortality rates of such defined disease. Fortunately, global malaria incidence and mortality is decreasing, dengue incidence and mortality is decreasing, cholera incidence is variable and mortality generally decreasing, and salmonella incidence and mortality is decreasing.

Where is the direct, observational evidence that these diseases are extending their range into areas that are presently unaffected other than obvious effects of commercial trade route changes? 

Claim: “It is expected that health losses due to climate change-induced undernutrition will occur mainly in areas that are already food-insecure.”

Observation: Deaths due to malnutrition are down very significantly, especially in Africa

Observation: Growth stunting in Africa continues to decrease. 

Where are the health losses due to undernutrition caused by climate change? Ironically, the most “food insecure” nations in Africa are the countries having substantial improvements in nutrition to the point that obesity is now becoming more prevalent. 

Claim: “Rising temperatures have increased the risk of heat-related death and illness (likely)”

Observation: Overall, we are having less heat related deaths and illness over time, not more

Observation: There are decreasing heat stroke hospitalizations, decreasing susceptibility to heat waves, and decreasing heat wave deaths, even when accounting for the introduction of air conditioners

Claim: “Greater risk of injury, disease, and death due to more intense heat waves and fires (very high confidence)”

Observation: Global fire incidence, severity, and loss trends are all decreasing. 

Observation: Global burn area has decreased. 

How can there be more intense heat waves if there are fewer diseases and deaths from those heat waves? How can there be a greater incidence of injury, disease, and death due to fires that are happening less often, and lower severity? If the IPCC claims “very high confidence”, shouldn’t this start showing up in the literature by now? Why hasn’t it? 

Now, I will turn to The 2022 Report of the Lancet Countdown on Health and Climate Change. As you may know, Lancet has established a vast repository of research and data to make the claim that climate change is a clear and present threat to humanity. I will compare and contrast the quality of scientific evidence they use to support their position. 

Claim: Exposure to extreme heat is associated with…impacts on mental health, worsening of underlying cardiovascular and respiratory disease, and increases in non-accidental injury related deaths. (Indicator 1.1 Health and Heat)

Observation: The single reference they use says nothing about climate change effects on cardiovascular or respiratory disease, or injury related deaths. It does claim a “2.2% increase in mental-health related mortality per 1 degree rise in temperature”, which of course is interesting as they don’t explain how low a temperature reading must go in order to eliminate the supposed added mortality risk. Additionally, I found a different study showing a decline in suicide (almost always tied to a mental health problem) rates between 1990 and 2015 that counters their argument since we are gradually warming with time.

Claim: Change in labour capacity—headline finding: in 2021, heat exposure led to the loss of 470 billion potential labour hours, a 37% increase from the period 1990–99. 87% of the losses in low HDI countries were in the agricultural sector (Indicator 1.1.4)

Observation: Despite their heavy reliance on a host of ill-defined outcomes, like  “lost labor hours” due to heat, GDP output for Sub saharan Africa seems quite stable over the past 60 years. Again, where is the signal that losing productive work hours leads to lower income levels? Or that they are even losing work hours at all? Ah, the modeling studies shine again. 

Claim: 37% of heat-related deaths are attributable to human-induced climate change.

Observation: We already know that global heat related mortality has been declining, as stated previously. How do we now get over ⅓ of all global heat related deaths as being caused by climate change, when we had more heat related deaths 50 years ago, yet less climate change to cause those deaths?  Something smells fishy. The answer lies in the study itself. It’s a modeling study, not a real world observation. And there is your answer. This is why I don’t trust modeling studies in general. 

The rest of the Lancet report is quite entertaining for someone like me. Using graphs depicting “average number of months suitable for malaria transmission” or “area of coastline suitable for outbreaks” without talking about “malaria incidence and mortality trends” or “cholera incidence and mortality trends” makes me chuckle. I think that deep down, someone at Lancet knows they’ve been had. 

I have a lot more too, this is just the opening section.  I look forward to your rebuttal. 


Scott Hastings, D.O.

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