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How climate change could make our food less nutritious

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    Yogi Berra, a US baseball player
    and philosopher, said,
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    "If we don't know where we're going,
    we might not get there."
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    Accumulating scientific knowledge
    is giving us greater insights,
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    greater clarity, into what our future
    might look like in a changing climate
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    and what that could mean for our health.
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    I'm here to talk about a related aspect,
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    on how our emissions of greenhouse gases
    from burning of fossil fuels
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    is reducing the nutritional
    quality of our food.
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    We'll start with the food pyramid.
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    You all know the food pyramid.
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    We all need to eat a balanced diet.
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    We need to get proteins,
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    we need to get micronutrients,
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    we need to get vitamins.
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    And so, this is a way
    for us to think about
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    how to make sure we get
    what we need every day
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    so we can grow and thrive.
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    But we eat not just because we need to,
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    we also eat for enjoyment.
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    Bread, pasta, pizza --
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    there's a whole range of foods
    that are culturally important.
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    We enjoy eating these.
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    And so they're important for our diet,
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    but they're also important
    for our cultures.
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    Carbon dioxide has been increasing since
    the start of the Industrial Revolution,
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    increasing from about
    280 parts per million to over 410 today,
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    and it continues to increase.
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    The carbon that plants need to grow
    comes from this carbon dioxide.
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    They bring it into the plant,
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    they break it apart
    into the carbon itself,
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    and they use that to grow.
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    They also need nutrients from the soil.
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    And so yes, carbon dioxide is plant food.
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    And this should be good news,
    of rising carbon dioxide concentrations,
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    for food security around the world,
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    making sure that people
    get enough to eat every day.
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    About 820 million people in the world
    don't get enough to eat every day.
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    So there's a fair amount written
    about how higher CO2
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    is going to help with
    our food security problem.
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    We need to accelerate our progress
    in agricultural productivity
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    to feed the nine to 10 billion people
    who will be alive in 2050
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    and to achieve the Sustainable
    Development Goals,
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    particularly the Goal Number 2,
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    that is on reducing food insecurity,
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    increasing nutrition,
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    increasing access to the foods
    that we need for everyone.
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    We know that climate change
    is affecting agricultural productivity.
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    The earth has warmed
    about one degree centigrade
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    since preindustrial times.
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    That is changing local temperature
    and precipitation patterns,
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    and that has consequences
    for the agricultural productivity
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    in many parts of the world.
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    And it's not just local changes
    in temperature and precipitation,
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    it's the extremes.
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    Extremes in terms of heat waves,
    floods and droughts
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    are significantly affecting productivity.
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    And that carbon dioxide,
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    besides making plants grow,
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    has other consequences as well,
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    that plants, when they have
    higher carbon dioxide,
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    increase the synthesis of carbohydrates,
    sugars and starches,
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    and they decrease the concentrations
    of protein and critical nutrients.
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    And this is very important for how we
    think about food security going forward.
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    A couple of nights ago
    in the table talks on climate change,
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    someone said that they're
    a five-sevenths optimist:
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    that they're an optimist
    five days of the week,
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    and this is a topic
    for the other two days.
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    When we think about micronutrients,
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    almost all of them are affected
    by higher CO2 concentrations.
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    Two in particular are iron and zinc.
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    When you don't have enough iron,
    you can develop iron deficiency anemia.
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    It's associated with fatigue,
    shortness of breath
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    and some fairly serious
    consequences as well.
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    When you don't have enough zinc,
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    you can have a loss of appetite.
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    It is a significant
    problem around the world.
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    There's about one billion people
    who are zinc deficient.
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    It's very important
    for maternal and child health.
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    It affects development.
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    The B vitamins are critical
    for a whole range of reasons.
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    They help convert our food into energy.
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    They're important for the functions
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    of many of the physiologic
    activities in our bodies.
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    And when you have
    higher carbon in a plant,
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    you have less nitrogen,
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    and you have less B vitamins.
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    And it's not just us.
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    Cattle are already being affected
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    because the quality
    of their forage is declining.
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    In fact, this affects
    every consumer of plants.
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    And give a thought to, for example,
    our pet cats and dogs.
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    If you look on the label
    of most of the pet and dog food,
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    there's a significant amount
    of grain in those foods.
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    So this affects everyone.
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    How do we know that this is a problem?
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    We know from field studies
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    and we know from experimental
    studies in laboratories.
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    In the field studies --
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    and I'll focus primarily
    on wheat and on rice --
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    there's fields, for example, of rice
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    that are divided into different plots.
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    And the plots are all the same:
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    the soil's the same,
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    the precipitation's the same --
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    everything's the same.
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    Except carbon dioxide
    is blown over some of the plots.
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    And so you can compare
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    what it looks like
    under today's conditions
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    and under carbon dioxide conditions
    later in the century.
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    I was part of one of the few studies
    that have done this.
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    We looked at 18 rice lines
    in China and in Japan
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    and grew them under conditions
    that you would expect
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    later in the century.
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    And when you look at the results,
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    the white bar is today's conditions,
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    the red bar is conditions
    later in the century.
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    So protein declines about 10 percent,
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    iron about eight percent,
    zinc about five percent.
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    These don't sound like really big changes,
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    but when you start thinking
    about the poor in every country
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    who primarily eat starch,
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    that this will put people
    who are on the edge
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    over the edge into frank deficiencies,
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    creating all kinds of health problems.
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    The situation is more significant
    for the B vitamins.
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    When you look at
    vitamin B1 and vitamin B2,
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    there's about a 17 percent decline.
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    Pantothenic acid, vitamin B5,
    is about a 13 percent decline.
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    Folate is about a 30 percent decline.
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    And these are averages over
    the various experiments that were done.
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    Folate is critical for child development.
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    Pregnant women who don't get enough folate
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    are at much higher risk
    of having babies with birth defects.
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    So these are very serious
    potential consequences for our health
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    as CO2 continues to rise.
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    In another example,
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    this is modeling work that was done
    by Chris Weyant and his colleagues,
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    taking a look at this chain
    from higher CO2 to lower iron and zinc --
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    and they only looked at iron and zinc --
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    to various health outcomes.
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    They looked at malaria,
    diarrheal disease, pneumonia,
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    iron deficiency anemia,
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    and looked at what
    the consequences could be in 2050.
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    And the darker the color in this,
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    the larger the consequences.
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    So you can see the major impacts
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    in Asia and in Africa,
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    but also note that in countries
    such as the United States
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    and countries in Europe,
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    the populations also could be affected.
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    They estimated about
    125 million people could be affected.
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    They also modeled what would be
    the most effective interventions,
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    and their conclusion was
    reducing our greenhouse gases:
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    getting our greenhouse gas emissions
    down by mid-century
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    so we don't have to worry so much
    about these consequences
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    later in the century.
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    These experiments, these modeling studies
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    did not take climate change
    itself into account.
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    They just focused on
    the carbon dioxide component.
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    So when you put the two together,
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    it's expected the impact is much larger
    than what I've told you.
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    I'd love to be able to tell you right now
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    how much the food you had for breakfast,
    the food you're going to have for lunch,
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    has shifted from what
    your grandparents ate
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    in terms of its nutritional quality.
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    But I can't.
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    We don't have the research on that.
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    I'd love to tell you how much
    current food insecurity
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    is affected by these changes.
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    But I can't.
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    We don't have the research
    on that, either.
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    There's a lot that needs
    to be known in this area,
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    including what the possible
    solutions could be.
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    We don't know exactly
    what those solutions are,
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    but we've got a range of options.
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    We've got advancements in technologies.
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    We've got plant breeding.
    We've got biofortification.
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    Soils could make a difference.
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    And, of course, it will be
    very helpful to know
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    how these changes could affect
    our future health
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    and the health of our children
    and the health of our grandchildren.
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    And these investments take time.
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    It will take time to sort
    all of these issues out.
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    There is no national entity
    or business group
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    that is funding this research.
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    We need these investments critically
    so that we do know where we're going.
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    In the meantime, what we can do
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    is ensure that all people
    have access to a complete diet,
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    not just those in the wealthy parts
    of the world but everywhere in the world.
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    We also individually and collectively need
    to reduce our greenhouse gas emissions
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    to reduce the challenges
    that will come later in the century.
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    It's been said that if you think
    education is expensive, try ignorance.
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    Let's not.
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    Let's invest in ourselves,
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    in our children
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    and in our planet.
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    Thank you.
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    (Applause)
Títol:
How climate change could make our food less nutritious
Speaker:
Kristie Ebi
Descripció:

Rising carbon levels in the atmosphere can make plants grow faster, but there's another hidden consequence: they rob plants of the nutrients and vitamins we need to survive. In a talk about global food security, epidemiologist Kristie Ebi explores the potentially massive health consequences of this growing nutrition crisis -- and explores the steps we can take to ensure all people have access to safe, healthy food.

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Video Language:
English
Team:
closed TED
Projecte:
TEDTalks
Duration:
11:00

English subtitles

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