We all know what climate change brings.
It brings changes in weather with more extremes of heat, precipitation and storms. It brings changes in sea levels and broadens the range major vectors of disease like mosquitoes.
Here’s another one to contemplate. A new study has demonstrated for the first time the damaging effect of climate change on the nutrients in our food
Published in the journal Nature Climate Change, scientists from the University of California Davis demonstrated that elevated levels of carbon dioxide restrict plants’ ability to transform nitrate into proteins.
The processing, or assimilation, of nitrogen by plants plays a vital role in their growth and productivity. It is especially important in food crops because these plants use nitrogen to produce proteins that are vital for human nutrition.
Other studies also have shown that protein concentrations in the grain of wheat, rice and barley – as well as in potato tubers – decline, on average, by approximately 8% under elevated levels of atmospheric carbon dioxide, say the scientists.
Given the role that these foods play in our day to day diets this could translate into an overall drop of around 3% as atmospheric carbon dioxide reaches the increased levels anticipated over the next few decades
There seems little doubt that the nutritional quality of food crops is at risk as climate change intensifies. And intensify it will, since for all our bleating and hand-wringing, and trying to read in the dim glow ‘eco’ light bulbs, we’ve done precisely nothing meaningful to alter the course of events.
To protect our foodshed we could try using more nitrogen fertiliser. But more than half a century of ‘green revolution’ has shown us the consequences of this: higher costs, nutrient imbalances in the soil, water contamination and algal blooms that kill aquatic life and increased emissions of the greenhouse gas nitrous oxide, which accelerate climate change further and faster.
You could argue that we probably get more protein in our daily diet than we already need, but this is not the point.
The point is that the drop in the nutritive value of our food caused by climate change is just one more attack in a long line of anthropogenic assaults.
For decades conventional industrial agricultural practices have wreaked havoc on our food. For example, a well-known research paper by British geologist-turned-nutritionist David Thomas looking at these nutrient declines between 1940 and 1991 in a selection of vegetables, showed dramatic declines in calcium, iron, magnesium copper and potassium.
A 2002 update of this work showed that these declines have continued. This problem is a direct result of growing crops soil that has been depleted by common agricultural practices.
Thomas’ findings were not unique. In a 1997 study published in the British Food Journal, researchers documented a similar historical decline in the mineral contents of 20 common fruits and vegetables between 1930 and 1987.
Another review was carried out in the US in 1999 when nutritionist Alex Jack compared nutrient values in the current US Department of Agriculture (USDA) handbook with those published in 1975.
His findings were so disturbing that in March 2001, Life Extension magazine also took up Mr Jack’s causeand, with his help and again using USDA nutrient tables (this time from 1963), ran its own comparison.
The results? The vitamin C content in a serving of peppers has plummeted from 128 mg then to 89 mg now. The beta carotene in apples has dropped from 90 mg to 53 mg. Broccoli and collards (greens) have lost half their total beta carotene content, and cauliflower’s vitamin C content has also declined by 50%.
Climate change and depleted soil are not the only threats to our food and our health. Many classes of herbicide including those used on GMO plants can alter plant metabolism and, thus, nutrient composition.
The metric is pretty simple; and it doesn’t matter whether you live in the ‘rich’ developed world or the ‘poor’ developing world. The outcome will be the same. Lack of adequate nutrition from food equals greater susceptibility to disease. Anything that impacts the nutritional value of our food will eventually impact on our health and wellbeing.
We should be taking this seriously.
Pat Thomas, Editor
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