As Carbon Dioxide Levels Rise, Major Crops Are Losing Nutrients | Hacker News Reader

As Carbon Dioxide Levels Rise, Major Crops Are Losing Nutrients

npr.org

65 pointsclumsysmurf32 comments

All the crops discussed bear little resemblance to their 'natural' versions. They have been bred to maximize yields and attractiveness to customers. This will continue unimpeded regardless of CO2.

What happens if CO2 goes up? Plant strains that grow well in high CO2.

What happens if CO2 goes down? Plant strains that do well in low CO2.

Hype.

> The extra CO2 seems to be making them grow faster.

I don’t see how this is suprise, a high CO2 world will be a greener world ironically.

false optimism -- greener means the right mix of water, heat and atmosphere ..

CO2 is good for photosynthesis but high temperatures are bad for photosynthesis. The end result depends on the particular species of plant and regional climate details.

Does "bad for photosynthesis" mean less green, or more green? Warm non dry places aren't usually short on green.

Any place with enough liquid water will tend to be pretty green regardless but it means that the plant will be able to chemically store less energy from sunlight and plants won't grow as quickly.

The more you warm things up the faster water evaporates and so the demand for water goes up. A place that has enough water to be green now may not have enough water to be green if temps go up by very much.

Same goes for eutrophication. At least initially before more adapted species take over, disturbing the existing ecosystem and reducing diversity. Or even causing anoxic, dead waters. https://en.wikipedia.org/wiki/Anoxic_waters#Human_caused_ano...

A high CO2 world will have higher global warming and coastal flooding, leading to less greenery.

>Scientists also don't understand what it is about higher CO2 that causes plants to become less nutritious, Ziska says, though they have some theories.

Dude. Look at the soil, not the plant.

Maybe the beneficial bacteria/worms/organisms are having trouble with increased carbon dioxide.

I mean, if plants like more carbon dioxide, maybe it's the things under the plants that don't?

edit: I emailed Ziska just in case

or this is just another "correlation without causation" between nutrients in plants and CO2 level. However, you might be onto something, as questioning our current agro-industry heavily relying on pesticides rather than focusing on building an ecosystem. No till direct seeding under cover is particularly interesting alternative.

My assumption would be that the root systems don't take up the extra minerals and nutrients any faster, but the plant grows faster, leading to the ratios being off.

So if you took the two plants, grown in low-CO2 and high-CO2 conditions, and reduced them to constituent atoms, you might find that the two plants have the exact same amount of iron by mass, but the high-CO2 plant masses more overall, leading to less iron per gram of edible plant material.

Or you end up with more iron concentrated in the leaves or stalks, and less in the grain, or ...

Living organisms are complex balancing equations of thousands of chemical reactions running simultaneously, with the rates at which they run interacting as one reaction produces or consumes the input to another. Increasing the availability of CO2 causes some reactions to run faster, but what happens after that is really, really complex. If a reaction that was bound by the availability of CO2 previously becomes unbound, some processes will run faster, but if process A and process B compete for a common input X, and process A is running faster because of increased CO2 availability, process B may now run slower because X is being depleted faster than usual.

Some problems like this may be solvable, but it's terribly complex and some of the solutions will have more side effects and some solutions will be really tricky to figure out. 60, 70% of agriculture is about maintaining a consistent environment for your plants to grow in, with the same amount of sunlight, the same amount of water, and the same concentration of soil nutrients as you have found in years past to produce the best results.

The prospect of having to rediscover what the new optimal values for all of the parameters you currently juggle, whether you are growing tomatoes, grapes or corn, is ... interesting.

If I'm not mistaken, that's how some herbicides work: by making certain parts of the plant grow faster than what the roots can deliver, thus killing the plant.

This will be a really hard relationship to properly measure because the answer is both to varying degrees - depending on the species. Plants absorb tons of nutrients from symbiotic colonies but they also regulate how much and how fast they absorb those nutrients using a variety of chemical and physical means. Figuring out those relationships is an intractable problem with current technology (which isn't even capable of isolating or identifying most bacteria)

This is really easy to demonstrate on the plant side with cannabis: start out with some clones in your choice of grow medium and grow them until you can seal a nonpermeable material over the top of the plant (around the stem but above the medium so that the flowers/lighting is separated from it). Then, control the CO2 in the cavity so that the leaves and most of the stem is in high-CO2 conditions and the medium in atmo. Compared with plants that grew entirely in high CO2 and entirely in regular conditions using the same lighting/nutrition/medium.

Once you've got a large enough sample size to weed out the noise, the effects are rather pronounced: high CO2 significantly increases the size of the buds, which increases the absolute amount of THC in the plant relative to its root network size, apparently depriving several other metabolic pathways of nutrients. The concentration of terpenes and other cannabinoids will be significantly lower in the high CO2 plants regardless of whether only the flowers were in high CO2 or everything was (at least, that was the result with a common Sour Diesel strain on a 200 plant sample size).

That's a lot of factors to control for but there is a lot of underground research into this very topic because the quality of cannabis can vary dramatically based on small changes in growing conditions. Figuring out the various relationships between timing/CO2/temperature/lighting/nutrients and the active ingredients in the final product is worth a ton of money so I'm hoping that industry will make some headway into this research field.

> The extra CO2 seems to be making them grow faster.

Thus more plant, thus less nutrients available per unit volune of plant, thus less nutritious.

It really depends on what "grow" means.

This seems to assume that there is a fixed amount of nutrients available per plant. Can you state why you think that's a valid assumption?

(I mean, yes, there is a fixed amount available, the total amount of nutrients contained in the soil available for the plant to pull nutrients from. But do you have some reason to think that plants are running into that limit?)

If a plant takes longer to grow, it consumes more water, and thus more nutrients, during it's growth period.

It's one of the reasons why really cheap (highly efficient) commercially farmed produce these days tastes "watery" to some degree.

Losses of ten percent on these nutrients do not seem like that big of a deal. Worst case we can enrich. Climate change is an enormous problem. But the nutrient levels in rice are an invisibly small speck on the face of that problem.

Don’t get me wrong. This is interesting, and the research is important. But this comment is for people like me who sometimes feel the news is about to make them hyperventilate. You can skip that for this one.

I think the impact is greatest on those who rely on rice as the majority of their sustenance and can not afford to purchase enriched goods or supplements.

How do you enrich rice?

Not only can you do it, it's Federally mandated in the U. S.: https://www.law.cornell.edu/uscode/text/7/1431c

As to how, my understanding is that it's just coated with nutrients; easy peasy.

Thanks

A lot of people wash rice before cooking it which also washes the enrichment off it.

Through genetic engineering. For instance https://en.wikipedia.org/wiki/Golden_rice

Ten percent is a big deal if you're already malnourished, as 11% of the world currently is[1].

I don't disagree about enrichment, but this is a pretty big problem in terms of eliminating poverty and minimizing (or improving) subsistence farming.

[1]: http://www.fao.org/state-of-food-security-nutrition/en/

Rice is a staple for more than half the human population in the world, and hence anything that affects its nutrition profile is bound to have a huge effect on several countries, their policies on healthcare, hunger alleviation and poverty alleviation. Enriching rice may not be easy to do at this scale across many countries.

The Wikipedia article on rice [1] says:

"Rice is the staple food of over half the world's population. It is the predominant dietary energy source for 17 countries in Asia and the Pacific, 9 countries in North and South America and 8 countries in Africa."

[1]: https://en.wikipedia.org/wiki/Rice

10% is a very big deal. We talk about trying to 'eat healthy', but what happens when all your food is becoming less healthy? This is a tragedy of a worldwide commons. Because it's not just rice, extrapolating from it, this is something that affects all plants globally. And it isn't just humans that are affected: this affects the animals that eat plants. What happens to environmentally stressed endangered species who now get less nutrient value from what they eat? This isn't an isolated study: people have been looking at this (albeit with little funding) for 20 years.

https://www.sciencedirect.com/science/article/pii/S016953470...

https://www.politico.com/agenda/story/2017/09/13/food-nutrie...

OT: All the EU 'Data Protection Choices' pages I've seen require JavaScript, when the content behind them usually does not. Why is that?

Tracking

So basically, in a high CO2 environement, plants grow faster and bigger, but they are less dense. Like biology 101.

This kind of pseudo-sciense, it’s the reasons we have so many climate skeptics.

This article also forgets to mention the reverse apply to animals too. High O2 means taller animals but less density in bones and muscles.

That's not entirely true, and it's not as simple as you surmise. The article says that this effect is not seen in some plants, like maize. It also mentions a case where protein, iron and zinc are lower, but Vitamin E is higher.

Calling this pseudoscience and biology 101 is a very poor choice of words and shows a poorer understanding of the contents of the article.

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