[music playing]
- Everyone knows that Earth gets light energy
and heat energy from the Sun,
but what happens to this energy?
Some of the energy gets absorbed by the atmosphere,
oceans, the land,
but some of it gets reflected back to space.
Sounds complicated, doesn't it?
Let's talk to Patrick Taylor from NASA
to find out what Earth's energy balance is all about.
- Earth's energy balance is really that.
It's just a balance
between the amount of energy that's coming in
and the amount of energy that's leaving the Earth.
So balancing Earth's energy budget
is a lot like balancing an equation.
We'll say X is incoming energy,
and that has to equal Y, which is outgoing energy.
So when these two are equal,
then we say Earth's energy is in balance.
So energy from the Sun comes to us in the form of light,
and that is-- it's also known as radiation.
It can be absorbed in the atmosphere.
It can also then be reflected back to space,
either by the clouds or by the polar ice caps,
a very bright surface.
The third thing that can happen too is,
it can be absorbed by the surface.
A total of 70% of the energy
is actually absorbed in the Earth's system,
and only 30% is reflected back to space.
Small changes in Earth's energy balance
can have very big impacts on Earth's climate,
changing the frequency of heat waves
and cold waves,
the frequency of hurricanes,
as well as our ability to farm,
the availability of fresh water and clean air,
impacting human health.
So we've been studying Earth's energy balance
for more than 40 years,
including the Nimbus 7 satellite,
the Earth Radiation Budget Experiment in the mid-1980s,
and also since the late 1990s
with the launch of CERES,
which is Clouds and the Earth's Radiant Energy Instrument,
and that's actually the science team that I'm a part of.
So to understand what controls Earth's energy balance,
we also observe a lot of other different types of information.
Having a steady supply of data is really important,
especially for studying Earth's energy balance.
The small changes in Earth's energy balance
make a really big impact on Earth's climate,
and having a long data record is really important
for assessing those changes.
Earth's energy budget is essentially
adding up all of the terms,
but when Earth's energy budget equals zero--
so if you have incoming energy plus outgoing energy,
and they equal zero, or they balance each other,
that's when you have Earth's energy balance.
- More energy coming in than what you give off,
and the system will heat up.
More energy going out than coming in,
and the system will cool down.
Planet Earth with its atmosphere
has just the right balance for life to thrive,
and that's what makes Earth a great place to live,
no matter what the weather.
Hey, here comes the sun!
See you next time on "Real World."