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  • Yogi Berra, a US baseball player and philosopher, said,

  • "If we don't know where we're going, we might not get there."

  • Accumulating scientific knowledge is giving us greater insights,

  • greater clarity, into what our future might look like in a changing climate

  • and what that could mean for our health.

  • I'm here to talk about a related aspect,

  • on how our emissions of greenhouse gases from burning of fossil fuels

  • is reducing the nutritional quality of our food.

  • We'll start with the food pyramid.

  • You all know the food pyramid.

  • We all need to eat a balanced diet.

  • We need to get proteins,

  • we need to get micronutrients,

  • we need to get vitamins.

  • And so, this is a way for us to think about

  • how to make sure we get what we need every day

  • so we can grow and thrive.

  • But we eat not just because we need to,

  • we also eat for enjoyment.

  • Bread, pasta, pizza --

  • there's a whole range of foods that are culturally important.

  • We enjoy eating these.

  • And so they're important for our diet,

  • but they're also important for our cultures.

  • Carbon dioxide has been increasing since the start of the Industrial Revolution,

  • increasing from about 280 parts per million to over 410 today,

  • and it continues to increase.

  • The carbon that plants need to grow comes from this carbon dioxide.

  • They bring it into the plant,

  • they break it apart into the carbon itself,

  • and they use that to grow.

  • They also need nutrients from the soil.

  • And so yes, carbon dioxide is plant food.

  • And this should be good news, of rising carbon dioxide concentrations,

  • for food security around the world,

  • making sure that people get enough to eat every day.

  • About 820 million people in the world don't get enough to eat every day.

  • So there's a fair amount written about how higher CO2

  • is going to help with our food security problem.

  • We need to accelerate our progress in agricultural productivity

  • to feed the nine to 10 billion people who will be alive in 2050

  • and to achieve the Sustainable Development Goals,

  • particularly the Goal Number 2,

  • that is on reducing food insecurity,

  • increasing nutrition,

  • increasing access to the foods that we need for everyone.

  • We know that climate change is affecting agricultural productivity.

  • The earth has warmed about one degree centigrade

  • since preindustrial times.

  • That is changing local temperature and precipitation patterns,

  • and that has consequences for the agricultural productivity

  • in many parts of the world.

  • And it's not just local changes in temperature and precipitation,

  • it's the extremes.

  • Extremes in terms of heat waves, floods and droughts

  • are significantly affecting productivity.

  • And that carbon dioxide,

  • besides making plants grow,

  • has other consequences as well,

  • that plants, when they have higher carbon dioxide,

  • increase the synthesis of carbohydrates, sugars and starches,

  • and they decrease the concentrations of protein and critical nutrients.

  • And this is very important for how we think about food security going forward.

  • A couple of nights ago in the table talks on climate change,

  • someone said that they're a five-sevenths optimist:

  • that they're an optimist five days of the week,

  • and this is a topic for the other two days.

  • When we think about micronutrients,

  • almost all of them are affected by higher CO2 concentrations.

  • Two in particular are iron and zinc.

  • When you don't have enough iron, you can develop iron deficiency anemia.

  • It's associated with fatigue, shortness of breath

  • and some fairly serious consequences as well.

  • When you don't have enough zinc,

  • you can have a loss of appetite.

  • It is a significant problem around the world.

  • There's about one billion people who are zinc deficient.

  • It's very important for maternal and child health.

  • It affects development.

  • The B vitamins are critical for a whole range of reasons.

  • They help convert our food into energy.

  • They're important for the functions

  • of many of the physiologic activities in our bodies.

  • And when you have higher carbon in a plant,

  • you have less nitrogen,

  • and you have less B vitamins.

  • And it's not just us.

  • Cattle are already being affected

  • because the quality of their forage is declining.

  • In fact, this affects every consumer of plants.

  • And give a thought to, for example, our pet cats and dogs.

  • If you look on the label of most of the pet and dog food,

  • there's a significant amount of grain in those foods.

  • So this affects everyone.

  • How do we know that this is a problem?

  • We know from field studies

  • and we know from experimental studies in laboratories.

  • In the field studies --

  • and I'll focus primarily on wheat and on rice --

  • there's fields, for example, of rice

  • that are divided into different plots.

  • And the plots are all the same:

  • the soil's the same,

  • the precipitation's the same --

  • everything's the same.

  • Except carbon dioxide is blown over some of the plots.

  • And so you can compare

  • what it looks like under today's conditions

  • and under carbon dioxide conditions later in the century.

  • I was part of one of the few studies that have done this.

  • We looked at 18 rice lines in China and in Japan

  • and grew them under conditions that you would expect

  • later in the century.

  • And when you look at the results,

  • the white bar is today's conditions,

  • the red bar is conditions later in the century.

  • So protein declines about 10 percent,

  • iron about eight percent, zinc about five percent.

  • These don't sound like really big changes,

  • but when you start thinking about the poor in every country

  • who primarily eat starch,

  • that this will put people who are on the edge

  • over the edge into frank deficiencies,

  • creating all kinds of health problems.

  • The situation is more significant for the B vitamins.

  • When you look at vitamin B1 and vitamin B2,

  • there's about a 17 percent decline.

  • Pantothenic acid, vitamin B5, is about a 13 percent decline.

  • Folate is about a 30 percent decline.

  • And these are averages over the various experiments that were done.

  • Folate is critical for child development.

  • Pregnant women who don't get enough folate

  • are at much higher risk of having babies with birth defects.

  • So these are very serious potential consequences for our health

  • as CO2 continues to rise.

  • In another example,

  • this is modeling work that was done by Chris Weyant and his colleagues,

  • taking a look at this chain from higher CO2 to lower iron and zinc --

  • and they only looked at iron and zinc --

  • to various health outcomes.

  • They looked at malaria, diarrheal disease, pneumonia,

  • iron deficiency anemia,

  • and looked at what the consequences could be in 2050.

  • And the darker the color in this,

  • the larger the consequences.

  • So you can see the major impacts

  • in Asia and in Africa,

  • but also note that in countries such as the United States

  • and countries in Europe,

  • the populations also could be affected.

  • They estimated about 125 million people could be affected.

  • They also modeled what would be the most effective interventions,

  • and their conclusion was reducing our greenhouse gases:

  • getting our greenhouse gas emissions down by mid-century

  • so we don't have to worry so much about these consequences

  • later in the century.

  • These experiments, these modeling studies

  • did not take climate change itself into account.

  • They just focused on the carbon dioxide component.

  • So when you put the two together,

  • it's expected the impact is much larger than what I've told you.

  • I'd love to be able to tell you right now

  • how much the food you had for breakfast, the food you're going to have for lunch,

  • has shifted from what your grandparents ate

  • in terms of its nutritional quality.

  • But I can't.

  • We don't have the research on that.

  • I'd love to tell you how much current food insecurity

  • is affected by these changes.

  • But I can't.

  • We don't have the research on that, either.

  • There's a lot that needs to be known in this area,

  • including what the possible solutions could be.

  • We don't know exactly what those solutions are,

  • but we've got a range of options.

  • We've got advancements in technologies.

  • We've got plant breeding. We've got biofortification.

  • Soils could make a difference.

  • And, of course, it will be very helpful to know

  • how these changes could affect our future health

  • and the health of our children and the health of our grandchildren.

  • And these investments take time.

  • It will take time to sort all of these issues out.

  • There is no national entity or business group

  • that is funding this research.

  • We need these investments critically so that we do know where we're going.

  • In the meantime, what we can do

  • is ensure that all people have access to a complete diet,

  • not just those in the wealthy parts of the world but everywhere in the world.

  • We also individually and collectively need to reduce our greenhouse gas emissions

  • to reduce the challenges that will come later in the century.

  • It's been said that if you think education is expensive, try ignorance.

  • Let's not.

  • Let's invest in ourselves,

  • in our children

  • and in our planet.

  • Thank you.

  • (Applause)

Yogi Berra, a US baseball player and philosopher, said,

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TED】Kristie Ebi: How climate change could make our food less nutritious (How climate change could make our food less nutritious | Kristie Ebi) (【TED】Kristie Ebi: How climate change could make our food less nutritious (How climate change could make our foo

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    林宜悉 に公開 2021 年 01 月 14 日
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