Translator: Rhonda Jacobs Reviewer: Peter van de Ven
Think of the food that you're going to eat today.
We're going to be served lunch, right?
And if you think that your food is going to contain plant products,
raise your hand.
Anything made from crops you're going to eat today?
I see a lot of hands, you know.
And that's not surprising, because plants are the foundation of our nutrition.
And if we're to gather in this theater next year
and eat exactly the same food,
made from crops grown in exactly the same conditions,
then they'll be slightly less nutritious.
And the year after that, it will be even less nutritious.
And that trend of declining food quality will continue for decades,
affecting not only our nutrition but also of our children.
And when I say that crops will be grown in exactly the same conditions,
that's not exactly true,
because CO2 concentrations - carbon dioxide concentrations -
next year will be slightly higher,
primarily because we burn fossil fuels.
And I'll be linking that increase in CO2 to drop in minerals
such as calcium, magnesium, potassium and zinc.
And our bodies can't make minerals, we have to get them from our food.
And these minerals, they keep our immune system and bones strong,
and our brain and heart healthy.
And, you know, a lot of the food is plants,
like rice and wheat provide about 40 percent of calories worldwide
but not enough nutrients.
For example, zinc deficiency affects about one billion people worldwide,
and new estimates show
that calcium deficiency affects 3.5 billion people -
every other person on earth.
And prospective mothers, they sometimes don't get enough iron,
and that affects not only them but also their babies.
And knowing that food quality is declining is not good news.
And you might be skeptical, not believe me,
and you're certainly not alone.
There are many scientists that were also skeptical of my claims.
And I'll share with you some of the challenges
of proving that it's true,
and I also hope that I'll convince you along the way.
Now, I've never really thought that I'm going to work on nutrition.
I was growing up as a mathematician -
to be a mathematician in Soviet Georgia.
And that program was kind of rigorous; it was mostly math classes.
I did have passion for ecology
but couldn't really take classes in ecology
but was reading some books on my own.
But then my mathematics studies get interrupted;
I get drafted into this military service.
I am sent to this secret military base, highly guarded, in Lithuania.
They have this nuclear warhead underground
and above it just a green pasture and a lake and cows.
And I'm assigned to be a guard.
And reading these ecology textbooks,
I learn that ecologists call grass
or any type of green plant, producers
because they use the energy of sunlight and CO2 to make starches, sugars.
This is a world's factory of carbohydrates.
They also take minerals from soil and water
to make organic matter, our food.
They produce food; that's why they're producers.
And those that consume them, like cows or us, consumers.
And so, there was a cow-taker position, so I applied and got it,
and all I had to do is take care of cows,
no guarding.
And I had to milk them twice a day.
But the irony of the Soviet Union
is that they have this sophisticated military equipment
but no milking machines.
So I had to milk cows twice a day with my hands.
I still remember how to do that.
(Laughter)
And I notice that the amount of milk I get from each cow -
you know, I was doing it manually -
depended not only on the amount of grass they ate
but also its quality.
That was interesting because according to traditional ecological theory,
it was mostly focusing on food quantity and not food quality.
And then once I finish my studies and my service,
the Soviet Union collapses,
and a lot of stuff becomes worthless,
like money and textbooks filled with history, ideology-based stuff.
But one thing holds its value and it's mathematics.
Fortunately for me because that's what I learn.
Because mathematics transcends all the boundaries -
political boundaries and geographical boundaries.
Mathematical equation in the Soviet Union works the same way as in America or here.
And so this allows me to come to Arizona State University
and continue my studies in math.
But I'm allowed to take courses in ecology,
and there I learn about this really interesting experiment.
So they grow this algae, phytoplankton, in those flasks -
these are producers also.
And they put different amounts of light on them,
and of course, the more light you put, you know, the more producers you get.
And then they feed that to zooplankton.
And now, you would think: more light, more food, more zooplankton.
That happened up to a point.
When there was a lot of light, you had a lot of food,
but zooplankton eating all that food
did really bad.
In fact, one of the experiments just died.
And the explanations ecologists gave was really neat.
You see, the amount of mineral phosphorus in those flasks was limited,
just as it is in real lakes and oceans.
And so when you put a lot of light, these things get a lot of carbon
but not enough phosphorus.
I mean, enough for them but not for the zooplankton.
So zooplankton was getting poor quality food.
So for my PhD thesis, I focused on making a simple model,
a mathematical model that will capture that effect.
(Laughter)
And so one equation describes producers;
another, consumers.
And, you know, the beauty about mathematics
is that it crosses not just geographical boundaries but species boundaries.
If something is true -
you know, nothing in those equations was specific to plankton -
then it should be also true for other species.
So for my post-doctoral work,
I moved to Princeton University and started to think,
well, they use light and CO2, right?
And when we increase light, photosynthesis goes up.
But we're not really increasing -
you know, we're not making our sun brighter
but we do increase CO2 concentrations.
And by the way, this is CO2 concentrations at the time: 371 parts per million,
and that was increasing every year.
So I'm thinking, huh.
What if that increase in CO2 can affect our food?
And then us?
So mathematics allows you to make this kind of transfer -
you know, parallel,
from this planting system to crops and humans -
by replacing light with CO2.
And I published it in a top ecological journal
and made this logical argument,
and I am at a top university,
and I naively think, okay, I kind of showed, proved that.
But ecologists, you know, they want evidence,
and we didn't really have evidence,
very few data.
And ecologists actually do raise plants at elevated CO2,
and they measure their growth and yield,
and sometimes they measure minerals,
but, you know, it's like measuring weather three times in Bratislava.
Are you going to detect global warming?
No, right?
You need a lot of data, and we didn't have them.
So I thought maybe we could generate data,
but everything went downhill.
So I moved to Nebraska - it's a crop state -
for my faculty position.
And it's a mathematics department.
So I applied to the mathematics division at National Science Foundation
to generate a more sophisticated mathematical model,
and they tell me, "You have too much biology there.
We don't really fund it.
Go apply to biology division."
So I come up with really, I think, a neat idea.
I write to these directors
of centers that raise plants at elevated CO2,
and I say, "Share samples with me.
So I'll pull all these samples, and then we'll analyze them."
And they agree; they agree in writing.
They say, "Sure, we'll share samples with you."
I put all these letters [together] and apply to the biology division.
And they tell me -
[REJECTED ... too much math]
(Laughter)
Right? Go somewhere else, essentially.
And I do. I apply to other places.
And for one or another reason get rejected.
It's a cross-disciplinary proposal; it doesn't really fit anywhere.
And then great recession happens.
And so, you know, my department wants to save money,
and I'm not bringing any money, any grant, so they cut me.
I become unemployed.
And I take my grant proposal and post it online,
so somebody, maybe who has money, could generate data.
But along the way, here's what I do:
Instead of pulling plant samples, which I don't have,
I pull data from the literature.
Little bit and by little bit, they publish the data on minerals.
And so I accumulate them. I don't have enough.
And by 2011, I run out of my savings,
so I apply to the government for food assistance.
And they misspell my name, but they actually give me -
this time they approve - they give me $200.
So I have to buy cheaper food for my family.
And when I start to buy cheaper food, I see it has more sugar in it.
And I'm like, wow, this Big Food industry injects sugar in our food supply
because it's very cheap for them to do.
And then I have at the time enough data
to actually see that rising CO2 does the same.
It injects more starches, sugars, and minerals drop.
And I'l tell you something weird.
I had felt at the time the time that I was the only, like, person in the world
who knew that's happening.
And the reason why probably I was
because next year, ecologists publish this paper,
and they say, "You know what? We'll also pull data,"
and there's no effect.
(Pfft) No change in grain quality.
In fact, if you look, say, at the grasses and zinc,
it actually increases.
Well, I say, "That can't be true."
Right?
I look at their sample size.
Their sample size is 2.
They essentially sell noise for actual signal.
And then their data contain so many errors
that to their credit, three years later, they retract their study; they cancel it.
But at the time, that was the last word
that affected the international panel on climate change
that in their fifth assessment said, "CO2 doesn't really change crop quality."
So I thought, okay, I had to publish it.
It took me two years of peer review, and then I publish this paper.
And it's called "Hidden shift" for two reasons.
First, when you look at your food, you can't really see the quality's lower.
Second, if you have a small sample, you can't see.
You have to have a massive amount of data.
And the "ionome" refers here to all these minerals, okay?
All these minerals that we get from food.
So, thanks to all these researchers
that were on four continents raising these plants at elevated CO2,
my data set covered 15,000 more -
15,000 observations of 130 plant varieties.
So, it was such a massive data set
that it cut through the noise and showed the signal.
And here's what happens:
Carbon increases in plants.
And all these minerals: calcium, magnesium and zinc and iron,
they decline.
Now, if we look at crops, major crops, for which we have data,
we'll also see that minerals decline in all major crops.
Now, that effect actually is global.
If you look at different latitudes, you could see it's in temperate regions,
and it is in tropical regions.
And for all the countries for which we have enough data,
that also happens there.
And what about type of experiment, right?
Some raise it in greenhouses - they elevate CO2.
Some do it in open fields
where there is continuously pumped CO2 concentrations.
Well, if you look at that,
in both experiments, minerals decline.
What about wild plants?
Does this just happen to crops?
Well, if you look at that, turns out it happens in wild plants as well,
and crops.
And it happens to little plants and big trees.
So the evidence was so compelling
that the next year, the US government calls me and says,
"You know, we're writing this report
about climate change and impacts on human health.
And can you help us?"
I say, "Sure."
So, in 2016, they produce a report,
but its key finding -
one of its key findings is that rising CO2 lowers food quality.
And it's one of only very few key findings that is of high confidence -
very likely to happen.
Couple of months later, I receive a letter from the White House,
from the Executive Office of the President.
So the US government that was declining all my grants all these years,
now thanks me for the service to the nation.
And what was more pleasing
[was] that America became the first industrialized country
that acknowledged that effect.
Now, that decline in crop quality and minerals -
its minerals declined like 5-10 percent - might not sound as big, right?
But think of it: Every time you're going to eat food
for the rest of your life,
all these minerals and protein will be replaced with carbohydrate -
empty calories.
And you know, I thought, I thought I have this effective ending for my talk.
I thought that this cumulative effect of extra carbs
would be maybe like a bucket, you know?
And I thought, I'm going to dump this bucket on me and show you that.
But when I actually did the calculations,
I realized, I better not do it
because if I'm going to dump all the amount on me at once,
it will kill me instantly.
So this is the amount of extra carbs we'll consume
instead of minerals and protein over our lifetime
as CO2 concentrations rise.
And you know, they give advice - finish a TED Talk with a call for action.
But I am not a policy maker; I'm not comfortable giving people advice.
I am a scientist; I usually answer questions or raise new questions.
So I want to finish this talk by raising this question.
How much these extra carbs and sugars we consume,
these empty calories because of rising CO2,
are going to affect diabetes and obesity
that is rising worldwide?
We don't know the answer to this question.
But I do hope those people that try to answer it
won't have to go through multi-year problems I went through
and will get the answer sooner.
Thank you very much.
(Applause)