Dr Shawn M. Carney
- Apr 15
- 8 min read

How Climate Change is Worsening Health: Increasing Rates of Allergies, Lyme Disease, and More (including Things You Can Do to Cool the Planet)

Climate change is a driving force behind health problems right here in the US, including seasonal allergies, asthma, Lyme disease and other tick-borne illness, as well as straining people with increased sensitivity to heat stress, which includes those with cardiovascular disease and diabetes, among others.

Our Changing Climate and Human Health

Human health is intricately linked to the climate and weather patterns that shape our environment. As climate change accelerates, the impact on human health becomes more pronounced, with existing health threats exacerbated and new ones emerging. The United States is already witnessing the effects of these changes, from more frequent and intense extreme weather events to rising sea levels and melting ice caps. Understanding the connection between climate change and human health is crucial for making informed decisions about mitigating future climate change and prioritizing measures to protect public health.

The evidence of climate change is undeniable, with extensive data confirming unprecedented shifts in air and ocean temperatures, sea levels, and the extent of snow and ice cover. Human activity stands as the primary driver of this warming trend. (1) The 2023 U.S. Fifth National Climate Assessment highlighted the disruptive impact of rising temperatures and related phenomena on various aspects of American life and the economy. (2) As we confront the realities of a changing climate, acknowledging the human influence on these shifts is imperative for devising effective strategies to safeguard both the planet and human health for generations to come. That climate change, which includes global warming, is worsening health is not a question, the question is how far it will go!

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Turning Up the Heat on Health

There are many types of adverse effects on health associated with climate change. These can include everything from acute occupational risk associated heat exposures like construction workers faced with increasing temperatures, rising risk of asthma from inhabiting areas of deteriorating air quality, or elevating exposure to extreme weather events with correlating disruptions to essential infrastructure and vulnerability to coastal flooding. And that's only scratching the surface on this topic!

However, our focus will be more on how the rising temperatures can compromise health in other less obvious areas.

And the temperatures are rising; as shown below, the previous decade is the hottest in recorded history and 2023 was Earth's hottest year on record! (4)

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Prevalence of Allergies

Over 50 million Americans suffer from indoor and outdoor allergies annually. (5) Allergies are the 6th leading cause of chronic illness in the U.S. with an annual cost in excess of $18 billion. (5) Food allergies, however, cost consumers about $25 billion each year. (6) And a child with an allergic parent has a 1 in 3 chance of developing allergies in their lifetime.

Allergies have been becoming more persistent and prevalent, in part, due to the constantly increasing length of time and volume of pollen that different plants have been producing. So what had previously been more concise periods of pollen dispersal have been becoming progressively longer, and increasingly overlapping. This has been attributed to climate change. (7) The net effect is that the 'allergy season' has been becoming longer and more onerous.

For example, ragweed pollen is one of the worst allergenic antigen triggers for many people. And look at how it has thrived with global warming. This data from 1995-2011 shows ragweed averaging extensions of the season by 2 to 4 weeks!

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Ticks Increasing in Number, Range, and Amount of Infectious Diseases They Are Known to Carry

Lyme disease has been known to be carried by ticks for many decades, specifically by Ixodes scapularis, the black-legged deer tick. But these ticks can carry many more pathogens and potential infections than just the organism responsible for Lyme disease. Back in 2004, a study from New Jersey found over 30% of ticks sampled carried Lyme disease as well as Bartonella species and a recent sampling from Newtown, CT found the rate of sampled ticks infected with Lyme disease as high as 50%! (9,10) Yet surprisingly Bartonella is still often not tested for when a person is bitten by a black-legged deer tick. Other infectious bacteria and protozoans carried by ticks, like Anaplasma, Ehrlichia, and Babesia, are more commonly tested in people and pets. But this list is by no means inclusive of all the possible infectious microbes such a tick can carry when it bites a person. That list continues to get longer, and has come to include even Powassan virus, which has a transmission time in as little as 15 minutes. (11,12)

But the list of types of infectious organisms from a black-legged deer tick is not the only factor in our worsening scenario with these arachnids; "[p]opulations of blacklegged ticks have established and flourished in areas of North America previously thought to be devoid of this species". (13) Ticks have been increasing in numbers as well as expanding their ranges. This is thought to be due, at least in part, to weather patterns and ecological factors. When the weather is warmer, spring starts earlier and people are outside more often, those conditions align to allow for more 'human-tick encounters'. Milder or wetter winters are also more favorable to ticks and there has definitely been a trend towards milder winters the last few decades. Indeed, as stated above, the previous decade is the hottest in recorded history!

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The warming climate is partially responsible for the tick expansion, as less colder temperatures allow these populations to gain a foot-hold into regions which historically they would not have been able to otherwise tolerate. And this is not just the black-legged deer tick, it applies to other types of ticks as well. Within the last few years, regions in Fairfield County, CT, reported established populations of two different kinds of ticks after having expanded their ranges, the Gulf Coast and Asian longhorn tick species. (10)

So given the environmental situation, it really is no surprise that incidence of tick-borne illness is on the rise. What is surprising is how ill-informed many physicians remain on the topic! If physicians across the country continue to only consider Lyme disease data for what was REPORTED to the Center for Disease Control and Prevention (CDC), they will see a comparatively low number of cases. However, if they consider alternatively how often these cases are being DIAGNOSED, they will see the magnitude of the problem is much bigger. (15,16) The CDC themselves have posted on their website that the number of DIAGNOSED cases of Lyme disease is more than ten times over and beyond the number of cases REPORTED to them, with the difference going from approxiamtely 63,000 cases to over 476,000 cases in 2019 . (17)

Further Complicating Leading Causes of Death

Current estimates and future trends in chronic health conditions that interact with the health risks associated with climate change are also unfavorable. Heart disease, stroke (as a distinct form of cerebrovascular disease), and diabetes are already all within the 'Leading Causes of Death' for the US population from 2021, totaling almost a million cases. (18) Sadly, the anticipated future trends of these conditions are expected to get even more common, with approximately 41% of the U.S. population projected to have some form of heart disease by 2030 and prevalence of diabetes increasing to 33% of Americans by 2050. (3) What does this have to do with climate change? Both cardiovascular disease and diabetes increase sensitivity to heat stress while some diabetic medications and dietary needs may increase vulnerability during and after extreme weather events. (3)

Things You Can Do To Cool the Planet

So what can we, as individuals, do about climate change? What can we do to cool the planet and try to reverse the tide?

Education, to begin with!

A great documentary released last year that explores how water, on the global scale, cools the planet, as well as how life on Earth sustains the climate, is 'Regenerating Life', by Hummingbird Films. It explores how global warming is not just from burning fossil fuels and increased carbon emissions but also from the re-radiation of heat from the planet, which is largely done by barren, unvegetated soil. It further explores how biodiversity and the interconnectedness of living organisms create a recipe for success on the larger global scale.

Later this month we are co-sponsoring a screening of 'Regenerating Life' in Newtown, CT. Join us!

But if you can't make the in-person showing, it is available to watch on Vimeo here.

Some of the action steps advised in the film to cool the planet include:

Re-covering and re-vegetating bare ground, which can be accomplished by use of cover-crops & by stopping deforestation
Support local agriculture! Either by growing your own garden and food OR by joining an already existing CSA (Community Supported Agriculture)
Help efforts to stop deforestation!
Support community-based energy! (instead of their corporate counterparts)
Don't support the over-production of meat nor over-fishing of the oceans - be a thoughtful consumer!
Get out there and see what you can do!

References:

The content and any recommendations in this article are for informational purposes only. They are not intended to replace the advice of the reader's own licensed healthcare professional or physician and are not intended to be taken as direct diagnostic or treatment directives. Any treatments described in this article may have known and unknown side effects and/or health hazards. Each reader is solely responsible for his or her own healthcare choices and decisions. The author advises the reader to discuss these ideas with a licensed naturopathic physician.

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