How Climate Change is Impacting The Nutritional Value of Your Food: Part 1, Carbon Dioxide

I still remember sitting in my Public Health Impacts of Climate Change course at Columbia Mailman School of Health (my elective choice while a Columbia nutrition MS student) learning about how climate change is impacting the nutritional value of food.

To sum it up, I was “shook,” as the cool kids say. It was actually one of the lectures in one of the classes that set my on my current path, and I gotta say, no regrets.

One of the most amazing and wonderful things about studying what I study (which is the intersection of nutrition and environmental health) is that I am honestly so interested in what I am learning about that I eagerly listen and complete my reading and assignments. Especially about things like climate change and how it is disrupting the quality, quantity, and nutritional value of our foods.

I thought this could make for an interesting and enlightening blog post that will perhaps leave you feeling “woke” on the topic, eliciting similar feelings to those I felt in my chair of Mailman room 1101 (shout out to my EHS crew). If this isn’t your thing or your find this super boring, don’t worry, I’m sure more dog and dessert pictures will be coming your way soon.

Anyways, read on to find out how climate change is impacting the nutritional value of your food.

It starts with rising CO2:

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If you’ve been paying attention to climate science at all in recent years, you’re probably aware that CO2 is rising at an unprecedented rate. While it’s normal for carbon levels to fluctuate with seasons, the continual upward trend since pre-industrial are largely a result of human fossil-fuel burning.

What is CO2 exactly? Well, CO2 is colorless gas and that makes up a minor component of the Earth’s atmosphere. CO2 is also considered a greenhouse gas, and is known to trap heat from the atmosphere.

It is formed via combustion of carbon-containing materials, in fermentation, is respired by humans and animals, and is used by plants for photosynthesis (keep this last point in mind as you continue reading).

How does CO2 Impact Plants?

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If you remember anything from elementary school science class and/or read the paragraph above, you may recall that CO2 is essential to plants and algae for photosynthesis, which is the plants mechanism of using sunlight, water, and carbon dioxide to make fuel to grow and reproduce. In fact, CO2 is the sole source of carbon for this process.

Skeptics will argue that carbon dioxide is plant food, and some go so far as to suggest that this is actually beneficial to crop growth and may enrich and benefit flora in some areas. One republican House Committee on Science argued in this un-cited piece that increasing carbon will aid crop production, lead to more nutrient-dense foods, and help alleviate poverty.

I’d like to take this opportunity to politely disagree. It is true that increasing levels of CO2 in the atmosphere may lead certain plants to grow more rapidly. But this isn’t always a good thing.

When a plant grows at a faster-than-usual rate, it has less time to absorb nutrients from the soil. Increased levels of CO2 may also impact a plant’s infrastructure, leaning to differences in growth of the leaves, stems, roots, and tubers (many of which, are edible parts we consume).

This leads to a different plant, and therefore, a different piece of plant-food on your plate.

The Nutritional Impact:

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Existing research on nutrient-density of crops grown in varying levels of CO2 suggests elevated CO2 can decrease concentrations of zinc and iron in C3* grains and legumes. Additionally, C3 crops grown in elevated atmospheric CO2 conditions had lower amounts of protein compared to those grown at lower levels of CO2.

Considering many people worldwide, particularly in developing nations, rely on grains and legumes as important source of protein, zinc, and iron, there is cause for concern.

In fact, a projection from Environmental Health Perspectives estimated that the decrease in protein levels of food crops including rice, wheat, barley, and potato, could potentially put additional 148.4 million people at risk of protein deficiency by 2050, equating to an increase of 1.6% of the global population.

Another study surveying over 15,000 plant samples of nearly 130 varieties showed that many micronutrients, including zinc, iron, potassium, magnesium, and calcium, had decreased by an average of 8% since 2012.

And some argue that the increased starch-content and decreased protein-content of plants grown with higher levels of CO2 are more difficult to digest for the human body.

It’s worth noting that not all crop plants are equally or negatively impacted by increases in CO2. For example, strawberries have been show to have increased antioxidant compound concentrations at elevated levels of CO2 (although, quick side note, too many antioxidants aren’t always a good thing).

It’s also worth noting that there isn’t a ton of research in this area yet, and we still have a lot to learn. What worries me, and many scientists who have devoted their careers to studying this topic, is that we aren’t studying it enough now to understand how to adapt for the future.

*C3 is a type of plant that is considered ‘normal’ and doesn’t have photosynthetic adaptations to reduce photorespiration.

And then, there’s invasive species…

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Some studies have suggested that CO2 increases may lead to increased growth of invasive plant species, which could present additional challenges for farmers in terms of yield and pest control.

It could also mean increased levels of pesticides are necessary, which in and of itself could have detrimental impacts on human and environmental health (but that’s another post entirely).

So where do we go from here?

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This is a question I ask myself a lot, as a student, food lover, and concerned citizen. Complex health-related issues stemming from human made climate change can seem difficult to detangle to approachable, actionable activities to the everyday person.

But we can all strive by educating ourselves and others, working diligently to reduce our own carbon emissions, and perhaps most importantly, working within our communities to push for policy and infrastructure changes that support the environment and our future. This may mean pestering your office to set up a recycling or composting system, and/or making sure you get your booty to the polls to vote for eco-minded individuals to represent you in the government.

Every effort counts. And if you love food and are worried about it, I hope this post gave you more reason than ever to act on combating climate change.

Have a delicious day! Part 2 (How Increasing Temperatures Impact Our Food) coming soon :-).

 

 

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