#11: Carbon is Making our Food Less Nutritious

This is a mini-episode covering one very interesting topic: Increased atmospheric carbon is making food grow with less nutrients. I cover the research and some of the implications for global health.

This is a fascinating story I wanted to share but couldn't fit it into a larger episode. So here it is in a short podcast bite.

Let me know what you think of this shorter format on social media:
https://twitter.com/GreenUrbanPod
https://www.instagram.com/greenurbanistpod


Sources:
https://www.politico.com/agenda/story/2017/09/13/food-nutrients-carbon-dioxide-000511/

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Transcript

Welcomes to the Green Urbanist. The podcast for urbanists fighting climate change.

Today I have a mini-episode for you. I am working on a much longer episode about livestock, climate change and ecosystems. But it's taking a bit longer than anticipated because I'm doing a lot of research for it. So in the meantime, I have found this really interesting bit of research that I wanted to share with you.

It should come as no surprise that a changing climate is having impacts on our food. Increased incidences of drought, flooding, and more changeable less dependable weather can clearly negatively impact on our food supplies. But there is one effect of climate change on food that you may not be aware of. Specifically this relates to the amount of carbon dioxide in the air.

If you remember back to your secondary school science classes you will know that plants absorb carbon dioxide and transform those carbon and oxygen molecules into carbohydrates that they use to grow. As we burn fossil fuels and pump carbon dioxide into the atmosphere, this has suddenly changed the chemical environment for plant growth. On one hand it may seem like it could be beneficial. More CO2 means more food for plants and so they should be able to grow bigger and faster - that's great for agricultural production, right? 

But researchers have recently uncovered a startling relationship. The more CO2 that plants absorb as they grow, the less nutrients they actually produce. As the extra carbon in the air provides fuel for a growth spurt, the plants do grow faster but they accommodate this pace by creating more carbohydrates, essentially sugar, at the expense of vitamins, minerals and protein. In the age of climate change, with a greater concentration of carbon dioxide in the atmosphere than ever before in human history, our food is becoming less and less nutritious. 

There is a fascinating article on Politico.com that discusses this phenomenon, which is chillingly titled, The Great Nutrient Collapse. A quote from one of the researchers interviewed in this article reads:  “Every leaf and every grass blade on earth makes more and more sugars as CO2 levels keep rising. We are witnessing the greatest injection of carbohydrates into the biosphere in human history―[an] injection that dilutes other nutrients in our food supply."

Actually, the fact that the nutritional value of our crops has been decreasing over the years is well known within the research community. Scientists have measured the rates of iron, protein, vitamin C and other key nutrients in crops like wheat and rice and have seen a clear decline over the last 70 years. One study from 2004 found that since 1940, the levels of these key nutrients in certain foods has fallen by one third.  

However, it was assumed that the reason for this was simply that intensive farming practices favour crop varieties that have a better yield rather than those that are the most nutritious and so over time we have just been growing more and more of these less nutritious varieties. That seems logical and may play a part in this. But recent experiments have shown a clear relationship between the carbon dioxide levels and reduced nutrients, a correlation that seems to be playing out all over the world.

Now this issue poses separate problems for wealthy developed countries and poorer developing ones. For us in the western world, our problem is too many calories. We produce and consume far too much low nutrient, high carbohydrate food as it is. The further dilution of our vegetables and crops just exacerbates this problem. But people who are conscious of their health will already be eating a diverse diet and with enough variety in your diet, you may not feel the negative effect of this. 

We have to understand that millions of people around the world rely on a very small number of foods to meet their nutritional needs. Rice, Corn and Wheat constitute two thirds of all human food consumption. So populations that are dependant on the slim nutritional provision of these grains are particularly fragile. A 2018 study found that the effect of carbon emissions on rice alone could imperil the health of 600 million. 

Back to that article in Politico, a round up of the recent research on this sums up the global nature of this problem:

In the summer of 2017, "a group of researchers published the first studies attempting to estimate what these shifts could mean for the global population. Plants are a crucial source of protein for people in the developing world, and by 2050, they estimate, 150 million people could be put at risk of protein deficiency, particularly in countries like India and Bangladesh. Researchers found a loss of zinc, which is particularly essential for maternal and infant health, could put 138 million people at risk. They also estimated that more than 1 billion mothers and 354 million children live in countries where dietary iron is projected to drop significantly, which could exacerbate the already widespread public health problem of anemia."

I don't have an easy solution for this. This sad story is reinforcing the belief I have that the climate emergency is changing our lives in ways we don't understand, or are only beginning to understand. It also provides another example of how climate change is hitting the developing world hardest - the people who live the least carbon intensive lives. These countries face the challenge of raising standards of living, reducing hunger and growing their economies while also reducing carbon emissions. Because this problem becomes a lot less acute once people have access to a more varied diet and more food overall to make up for nutritional deficiencies that arise when people have to live off of a few cheap ingredients like rice.

Perhaps the scariest aspect of this is, as I mentioned, it's been known for a long time that the nutritional content of our food has been reducing but this hasn't entered into political discourse or agricultural policy. It's a problem that's been acknowledged as an interesting trend but not something to actually take action on. In other words, it's accepted despite the huge implications for global health. 

I know this was a different kind of episode to normal, both in topic and length so let me know what you think on twitter and instagram. Please also subscribe or follow the podcast wherever you are listening so you don't miss future episodes.

That's it for today, Thanks for listening.