[music playing]
- We know that the energy from the Sun
is absorbed, reflected,
and sent back out into space
as part of Earth's energy balance.
But let's talk to a NASA scientist
to see what happens if we shake things up.
- Earth's energy balance is very delicate,
meaning that small changes can have a really big impact.
Some things that can make small changes
include changes in vegetation on land,
changing the area of the ice caps,
or changing the composition of the atmosphere,
including the amount of dust that's in the atmosphere
or the amount of carbon dioxide.
So for instance, if you change the amount of vegetation,
that will change the amount of sunlight
that is reflected back to space.
If you were to tear down a forest
and replace it with asphalt,
you would make the surface a lot darker,
and so the surface would absorb a lot more
of the solar radiation,
and then that would cause the area to heat up.
So if you reflected more solar radiation back to space,
Earth's energy balance would be thrown off,
because there would be a lot more energy
reflected back out to space than is coming in.
A volcanic eruption can spew more ash into the atmosphere,
and that would reflect more solar radiation back to space,
and this could then lead to the ice caps growing
and the Earth getting very, very cold.
If we tip the scales the other way,
and we cause more energy to stay
in the Earth's system than to leave,
then we would see the system would warm.
A very efficient way of doing that in the past
has been the increased carbon dioxide in the atmosphere.
That's caused it to get very, very warm in the past.
Understanding Earth's energy balance
is very important for climate.
If we can understand the factors
that control Earth's energy balance,
that allows us to make better predictions
of our future climate,
and making better predictions of the future climate, then,
will help humans thrive and survive on planet Earth.
- The temperatures of Earth and all the planets
are determined by their energy balance.
Just like opening a window in the winter,
anything that changes the amount of energy
coming in and going out
disturbs the energy balance.
But don't worry.
Until we fully understand the impacts
these changes have on Earth,
NASA will continue to keep an eye on Earth's energy balance.
For "Real World," I'm Mishay,
and I'll see you next time.