- I can't believe how pricey these spicy peppers were.
Get ready for some hot facts next on "Real World."
[futuristic music]
Why are some foods more expensive than others?
And why do some places have more
of one type of food than others?
It all boils down to food supply
and what plants need in order to grow.
- So there are many things that a plant needs
in order to grow.
They need water,
they need air,
they need nutrients that
they largely get from the soil.
They need sunlight or sunshine.
They need heat to grow.
They need time, of course. So they don't grow in one day.
They grow through time.
And what they do is, they use, through their roots,
they will carry up the nutrients
into the various parts of the crop
that will let them grow, develop,
and eventually create the fruit,
which is then what we harvest.
All of these are what we call natural resources.
Our Earth provides with a lot of natural resources,
and all of these are really important for life on Earth,
whether that's human life or the ecosystem
and crops or animals.
So NASA has a really important Earth-observing fleet
of satellites that are continuously
going around the world and providing
different types of information.
Satellite data are a great tool for us
to monitor this kind of information
and monitor that on a daily basis
to give us a global picture,
but that can give us information
all the way down at the field scale
around how crops are developing,
what we can expect the productivity is.
And the important part then is to convert that data
into information that decision-makers can use.
So crop yields are the harvested production
per unit of a harvested area of a crop.
You know, thinking about why is it important for us
to measure a ton of yield.
That's essentially giving us the measure of productivity
of a crop,
and when we multiply the yield
by the area of where it's produced,
that'll give us the total production,
which is generally-- oftentimes measured
in tons, themselves.
And that's giving us, essentially,
if we think about what our food supply is,
we need to care not only
what's happening in one country,
but our food system is really interconnected,
and so it's really important for us to understand
actually globally what's going on.
So if there's a drought, for example, in Russia,
it's one of the biggest exporters
of wheat to Egypt, and therefore, for bread.
So if Russia has a shortfall, right,
if Russia produces less than it normally would
or less than expected,
that has big implications for all the people
that are importing food from Russia,
and actually has implications globally
because when we have less food than what we expect
or less grain than what we expect,
that can have implications also across the world
in terms of increasing prices.
And vice-versa, when you have a lot of supply,
then the prices will go down
because you can meet all that demand
and more than what you have.
- So that's the data that NASA collects about food.
But how do we use that data, and what does it look like?
- There are a lot of data sets that come together
to help us forecast potential food shortages.
The most commonly-used band index is NDVI,
which is Normalized Difference Vegetation Index.
And it tells us something
about how healthy the crops are
and how green they are,
how much chlorophyll is in their leaves.
So high NDVI means really healthy crops;
low NDVI means very little vegetation.
Outliers are data points
that are substantially different
than the rest of the data set.
And maybe this is a sensor error,
or maybe a cloud got in the way
and resulted in a much different value
than the rest of the points.
But we also look at other variables
like the weather data, which might include
rainfall or temperature data.
We look at soil moisture, since healthy and moist soils
are important for crop growth.
The model might take in all of this evidence
and predict that food production
will be low in that region,
and then we can then pass that information along
to decision makers who can help
to prevent or mitigate the effects
of the potential food shortage.
Even though we can observe variables like NDVI,
weather, and soil moisture from space,
we need to use ground truth data
to know how what we're seeing
from space and the satellite images
matches up with what's actually happening
on the ground.
Many people use this information--
farmers are always looking to maximize their production;
governments care about how much food is produced,
where the food is being produced,
and the economic impacts of food production.
Much of this data is open source
and available to the public through NASA resources online.
- Sounds like a lot of math,
but it all adds up to understanding
how the world's food supply works
and how NASA's eyes in the sky
can help put food on your plate.
[bell dings]
Sounds like it's time for me
to put some food on my plate.
See you next time on "Real World."