It’s Hot Very Hot (somewhere) – So What!

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It cannot have escaped your attention that June and July in 2023 have had very high temperatures – with some areas in the world hitting their highest sequential hottest days ever recorded in their local history.

The world is warming at a faster rate than at any time in human history, due mainly to the burning of fossil fuels, with an important additional contribution through land-use changes, mainly for agriculture and forestry[1]. With intense heat waves leading to a summer of extremes marked by compound events, including high temperatures, drought, fire activity, and ozone air pollution, working out what can be done by each of us involved in health care is important[2].

Even optimistic projections show global emissions continuing to rise over the next decade before falling only gradually. CO₂ remains in the atmosphere for centuries so, even if emissions were reduced today, the atmospheric CO₂ concentration will continue to rise, pushing temperatures up.

No one knows with absolute clarity what will happen to sea levels, hurricane frequency and intensity, seasonal weather challenges, wildfires, acidification of oceans, and other measures of climate change, nor their impact on lost GDP, greater morbidity and mortality, and social disruption. We have no absolute theory from economics, climate science or elsewhere to turn to, nor totally impeccable data from either side of the climate change divisions to rely on. Our human population has never witnessed the effects of such a temperature rise on an industrial economy.

If we agree that we don’t know (for certain) what our climate future will look like we can plan without becoming caught by some of the polarising opinion writers. We may be lucky and experience only moderate climate change with a limited economic and social impact. But we can’t count on luck. Now is the time to put more effort into efficient CO₂ emission reduction and invest in adaptation to limit the impacts of climate change, both at the macro and the micro level.

What can we do as individuals?

At the micro level, individual actions can have a substantial effect on reducing personal exposure to heat waves (currently relevant). Simple measures such as staying hydrated, wearing appropriate clothing, and avoiding outdoor activities during peak hours of heat can make a substantial difference. However, heat vulnerability is a complex issue, influenced by societal and behavioural determinants, such as social participation, working requirements, mental health, physical and cognitive functions. In addition, exposure to extreme heat may exacerbate pre-existing health conditions, causing further variation in vulnerability to heat.

The health risks of climate change can have both immediate and long-term consequences. Extreme weather events can lead to acute mental health conditions such as anxiety, depression, and post-traumatic stress. The cumulative effect of loss of livelihood, displacement, disrupted social cohesion and uncertainty from climate change can also result in longer-term mental health disorders[3]. Managing these challenges without relying on pharmaceutical interventions is an ongoing challenge but various natural, psychological and nutritional strategies continue to demonstrate effectiveness [4].

Changes in food production do and will have adverse effects on human health. Whilst some crops experience increased growth due to the raised levels of CO2 others are compressed resulting in loss of essential nutrients. In turn, resources required to grow crops – water and fertiliser – will see seasonal variations that include extreme events along with geopolitical challenges and will create nutrition-related risks and challenges.

A 25th July 2023 research report from The Health Foundation’s Real Centre projects a significant decline in the healthy population in England with 2.5m more projected to be living with a major NCD illness by 2040. This is without considering the pervasive impact of declining nutrient quality in the foods we eat due to climate change, albeit a large part of the progression is predicated on a non-resolving obesity crisis.

Elevated CO2 and our food

Elevated CO2 has been shown to increase the fructose, glucose and total soluble sugar content and to decrease the protein, nitrogen, magnesium, iron, and zinc content of vegetables[5].

For root vegetable species, elevated CO2 was found to result in significantly higher yields, yet significant decreases in protein, vitamin C and fat content in carrot, radish and turnip. Additionally, all three of these vegetables showed an increase in sugar and fibre when exposed to higher levels of CO2. Meaning that the intake of sugars starts to exceed the counter balancing benefits of the related nutrients and fibre.

Elevated CO2 also decreased the amounts of fatty acids, amino acids and a number of important minerals. Although these vegetables are generally currently high in nutrients, these findings suggest that future levels of elevated CO2 could in fact have a detrimental impact on the nutritional quality of root vegetables and alternative crops may need to be considered in future food systems.

However, it is the direct effect of rising CO2 on plant chemistry and stoichiometry that represents a continuing threat to the nutritional integrity of both human and animal systems.

The earliest acknowledgement of CO2 on nutritional aspects are by Sionit [6], reporting that leaves growing in elevated CO2 had higher carbohydrate levels, higher C:N ratios and lower leaf nitrogen. These observations have gained credence over time, including being confirmed in multiple meta-analyses[7]. In simple terms increasing CO2 will reduce protein and mineral concentrations of a wide variety of plant-based food sources, with substantial global consequences for human and animal nutrition.

Supplements to Bio-Fortify Yourself

Here are some important micronutrients to manage and supplement and their potential relevance during times of rising global temperatures:

Vitamin D: With higher temperatures, people spend more time indoors to avoid extreme heat, reducing their exposure to sunlight, which is the primary source of vitamin D synthesis in the skin. Vitamin D is essential for bone health, immune function, and overall well-being.

Vitamin B12: Climate change can affect the distribution and availability of certain foods, including those rich in vitamin B12, such as seafood and some animal products. Vitamin B12 is critical for nerve function, red blood cell production, and DNA synthesis.

Iron: Changes in temperature and rainfall patterns can impact crop yields, potentially leading to lower iron intake due to reduced consumption of iron-rich foods like leafy greens and fortified grains. Iron is crucial for oxygen transport in the body and overall energy levels.

Zinc: Rising temperatures and water scarcity might affect the zinc content of crops, leading to potential deficiencies. Zinc is involved in various enzymatic reactions and is essential for immune function, wound healing, and growth.

Iodine: Changes in sea levels and temperatures can impact the iodine content of seafood, a primary source of this micronutrient. Iodine is crucial for thyroid function and overall metabolism.

Vitamin A: Climate change-related events like floods and droughts can disrupt food production and distribution, potentially impacting the availability of vitamin A-rich foods. Vitamin A is essential for vision, immune function, and skin health.

Omega-3 Fatty Acids: Rising ocean temperatures can affect the distribution and availability of fish, which are a rich source of omega-3 fatty acids. These essential fats play a role in heart health and brain function.


Never has the expression ‘root cause medicine’ been more relevant; soil health and related nutrient density varies greatly by region but is universally declining. We are all of the soil, and its related minerals and nutrients. Organic farming offers advantages as does the self-generation of food where possible. But on a global scale, this is a much more challenging issue to resolve. Biofortification of soils, crops and humans is a valid and essential mechanism to limit the related loss of essential nutrients. Because the human organism cannot generate any element that is lost through excretion, we must replenish it from our food. Plants are the basis of human nutrition, providing a staggering 84% of calorie intake worldwide.



[1] Intergovernmental Panel on Climate Change. in Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (eds. Masson-Delmotte, V. et al.) (Cambridge Univ. Press, 2021)

[2] The Lancet Planetary Health. Be prepared for more heat. Lancet Planet Health. 2022 Sep;6(9):e706.

[3] Thompson R, Lawrance EL, Roberts LF, Grailey K, Ashrafian H, Maheswaran H, Toledano MB, Darzi A. Ambient temperature and mental health: a systematic review and meta-analysis. Lancet Planet Health. 2023 Jul;7(7):e580-e589.

[4] Joschko L, Pálsdóttir AM, Grahn P, Hinse M. Nature-Based Therapy in Individuals with Mental Health Disorders, with a Focus on Mental Well-Being and Connectedness to Nature-A Pilot Study. Int J Environ Res Public Health. 2023 Jan 25;20(3):2167

[5] Hannah Chumley & Susan Hewlings (2020) The effects of elevated atmospheric carbon dioxide [CO2] on micronutrient concentration, specifically iron (Fe) and zinc (Zn) in rice; a systematic review, Journal of Plant Nutrition, 43:10, 1571-1578

[6] Sionit N., Mortensen D.A., Strain B.R., Hellmers H. Growth Response of Wheat to CO2 Enrichment and Different Levels of Mineral Nutrition. Agron. J. 1981;75:1023–1027.

[7] Chumley H., Hewlings S. The effects of elevated atmospheric carbon dioxide [CO2] on micronutrient concentration, specifically iron (Fe) and zinc (Zn) in rice; a systematic review. J. Plant Nutr. 2020;43:1571–1578

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