PRESENTER: This is from the
site of the United States
Department of Agriculture.
Maize, which is what's
shown here, is corn.
And we eat a lot of corn
and a lot of animals
eat a lot of corn.
Net photosynthesis is good.
This is turning sun's energy
into something we can eat.
And so up here, is eat
and down here is starve.
We don't eat if
nothing is growing.
And this is temperature, going
from fairly warm to really hot
up here, and in
degrees Fahrenheit,
there's 100 right there.
And what you'll notice is
for this particular one,
if you look at the rate
of photosynthesis, what
grows as it's affected by leaf
temperature, when the leaf gets
hot, growth slows a lot.
This is something
that's worrisome.
In the modern world,
a lot of places
where we grow corn and
other crops, on the hottest
day of summer they
don't grow very well
because it's actually
too hot for them.
And we face some possibility
that by late in the century,
the hottest summer that we've
ever seen until recently
will be considered cool.
And given this trend, that is
something that a lot of people
worry about.
