Why do solar panels
look so different these days?
And why have we started installing them
on top of mountains,
using them to pave our roads,
and putting them in the middle of our oceans?
Well, if we cover enough of our planet
in solar panels,
we'll have a good chance
of halting the planet's rising temperature,
and maybe even cooling it a few degrees.
But how would that work?
One way we could cool the planet
is through something known
as the albedo effect.
Albedo refers to the amount of light
that's reflected off a surface
without being absorbed.
For instance, if all of the Earth
were covered in ice,
the albedo would be around 0.84.
This means the Earth would reflect 84%
of the sunlight that hits it.
But if the entire Earth was covered by
a forest canopy,
that number would be about 0.14.
Only 14% would be reflected,
meaning that most of the sunlight
would be absorbed.
So, if we take a bunch of reflective things,
like solar panels,
and line the Earth with them,
the renewable energy they produce
would help to cool the Earth.
They'd also reflect a lot of heat away.
And then our planet would become
cooler in no time, right?
Not exactly.
Instead of our solar panels cooling the Earth,
it could make things hotter instead.
Although solar panels might look
super-reflective to us,
they'd do a pretty bad job
of reflecting sunlight into space.
Because solar panels are so dark,
they absorb sunlight.
This would increase Earth's ground temperatures.
Plus, according to the laws of thermodynamics,
we'd be creating even more heat
every time our solar panels
converted solar energy into electricity.
So, let's scratch that whole albedo idea.
If we're going to cool the Earth with solar panels,
it'll have to be by using them
to completely replace fossil fuels,
like oil, gas, and coal.
If we stop using fossil fuels,
we won't produce as much greenhouse gas.
Then we'll stop heating our planet up so much.
So how many solar panels
would we need to power everything on Earth?
If we're talking about a typical 350W solar panel,
it will take about 51.4 billion of them.
Imagine a solar power plant
that covers
299,467 square km (115,625 square mi).
That would about the size
of the U.S. state of Arizona.
To build this massive project,
lots of people would be needed
to manufacture the solar panels,
install them, and maintain them.
But it shouldn't be hard
to find a willing workforce.
After all, there will be a lot of
former fossil fuel industry employees
looking for jobs.
So all we have to do is retrain them,
and hope they don't complain too much.
We'll be dealing with plenty of
other complaints about this project.
People would complain about the noise
during construction,
the glare from the panels themselves,
and the increased traffic
from panel maintenance vehicles
in residential areas.
Plus, people might be upset about
decreasing property values,
especially if their view changes from
enjoying a beautiful landscape
to a massive solar farm.
For a large-scale project like this,
another issue would be land use.
Using land for the solar farm
would mean a potential loss of habitat.
And, unlike wind farms,
solar farms can't share the land with agriculture.
But maybe the most critical issue would be
producing the solar panels.
Manufacturing over 51 billion
solar panels would create harmful emissions.
To make them, we'd need to use chemicals,
including sodium hydroxide
and hydrofluoric acid.
Making the panels would
emit greenhouse gases and create waste.
So, if we try to cool down the Earth
using solar panels,
we might end up creating
more of the emissions
that heated our planet in the first place.
Maybe we need to stop looking for
a single solution
to our planet's heating problem.
If we start thinking of the Earth
like one living organism,
we'd see that we need to use
many different solutions,
and work together to address all its needs.
But that's a story for another WHAT IF.