Global Climate Change - YouTube

Hi. It's Mr. Andersen, and this is AP Environmental Sciences video 34.

It's on global climate change.

The climate is affected by essentially two things,

the amount of solar radiation we get and the greenhouse effect.

And so as these change over time the climate is going to fluctuate. We're going to have little ice ages.

We're going to have warming periods. The problem right now is the climate is changing too quickly.

The globe is heating up, and that global warming is caused by us.

We're increasing the amount of greenhouse gases in the atmosphere.

And so if we look at carbon dioxide levels in the atmosphere post industrialization,

we haven't seen these levels in the last four hundred thousand years.

And countries are going to be affected by this. The environment will be affected by this.

And so they've been meeting over the last two decades

at the UN Climate Change Conference as a way to figure out how we can reduce these greenhouse gases.

The first protocol was the Kyoto protocol. And then more recently in 2015 is the Paris Agreement.

You can see right here president Obama in the middle.

The US pledged for a 26 to 28 percent reduction in greenhouse gases.

China is going to peak their carbon Dioxide by 2030.

40% reduction in the EU.

37 percent reduction in Brazil.

But these are all simply pledges that they've agreed to. They're not legally binding.

The only thing that's legally binding is we're going to start monitoring the greenhouse gases.

And so we'll see how that plays out over the next five to ten years.

And so the climate is affected by the solar radiation and the greenhouse effect.

And as those change we get global climate change which can

impact the environment and therefore can impact the humans. The problem

we have right now is it's getting too hot too fast.

We can't really affect solar radiation so we look to the greenhouse gases as a culprit.

The five different ones that we'll talk about are

water, carbon dioxide, methane, nitrous oxide and then CFCs.

What they do in the atmosphere is they essentially trap infrared radiation.

Some of these sources are natural

So volcanoes for example are going to put carbon dioxide and water vapor into the atmosphere.

But a lot of these are Anthropogenic.

In other words, we're producing these and they're warming up the planet.

And so treaties are being signed to reduce the amount of greenhouse

gases in the atmosphere, to kind of mediate some of these human impacts.

Kyoto Protocol and Paris agreement are 2 that we'll talk about.

So how does the greenhouse effect work?

Well let's say that the Earth didn't have an atmosphere and clearly this model is all off

but if it didn't then light would come from the sun.

It would hit the planet a lot of that is reflected back into space,

but some of it is converted into infrared radiation.

It also would go into space. And so the earth would essentially be a ball of ice.

There wouldn't be enough heat to heat the planet.

And so what happens with an atmosphere is that we trap that.

So once it hits the planet that heat is left behind.

And so it warms it up. It works just like a greenhouse does on a warm day.

So if we look more specifically of what's going on with the greenhouse gases

This is a phet simulation.

And so what I'm going to do is I'm going to create an essential atmosphere.

So I'm going to put a little bit of nitrogen in the atmosphere.

We're going to put some oxygen in the atmosphere.

We're going to put in a little bit of water vapor in the atmosphere.

Now we've got some carbon dioxide and finally we have some methane. So this is our pretend

simulated atmosphere and as light moves through it you can see that it's not interacting with any of those gases.

That's how the light gets through the atmosphere to our planet. Once it hits the planet it converts to infrared radiation.

Watch what happens as that starts to leave the planet. You can see that some of these are are

refracting some of that infrared radiation. Instead of moving back into space it actually returns.

What are those greenhouse gases?

We can see methane. We can see water. We can see carbon dioxide.

But the oxygen and the nitrogen aren't impacted at all.

And so greenhouse gases are water vapor, carbon dioxide, methane

nitrous oxide and CFCs.

These are molecules in the atmosphere that trap that infrared radiation. A lot of those are made

through natural processes. And so carbon dioxide is produced in a

volcanic eruption like this. Also a lot of sediment moves into the atmosphere

which will actually cool the planet from a volcano.

Or this giant termite mound is going to produce methane gas that goes into the atmosphere.

The problem is that a lot of these are anthropogenic.

In other words we're making them. humans are making them.

And we're making them through agriculture, through power, through industrialization.

If we look at the three major culprits carbon dioxide, methane and nitrous oxide.

They're produced by different activities on our planet

but all of them are heating our planet. You can see that agriculture impacts a lot of especially methane and

nitrous oxide. And what it's doing is it's warming up our planet. You can see in all parts of our planet

we're seeing increases in temperature.

And some are predicting increases up to three or four degrees Celsius

change over time and so we have to start to mediate that.

Because what happens as we increase the temperature

is we're going to get a melting of glaciers,

snow cover goes away, polar ice caps go away, sea levels start to rise.

And as a result of these environmental impacts

we're going to have human impacts. So we're going to have droughts.

Forest fires may increase. The size of the storms are going to get greater

because we're going to have a higher amount of

radiation. And then we're going to have

increases in in the sea level. And so if you live near that

coast it's going to impact you.

If we look at human impacts these are all the humans that are going to be impacted.

If we look at first of all the blue it's hard to see but all the islands,

obviously, as the sea levels start to rise are going to be impacted.

Especially if you live around these deltas.

All these purple areas are going to be hurricanes. All these yellow areas are going to be droughts.

We're also going to see changes in disease.

Malaria is going to start to move to areas where it was never found before.

Those droughts are going to lead to decreases in agricultural yields.

And that's going to impact humans as well.

And so what do we do? countries are coming together.

This is a global problem. No one owns the atmosphere. we all own it together.

So we have to work together. And so the first was the Kyoto protocol. It was a reduction in greenhouse gases.

You can see that only the green countries were legally binding to reducing the amount of greenhouse gases.

A lot of them weren't legally bound. The US didn't ratify it. Canada pulled out after a year.

2015 again we have the Paris agreement where all these countries are making

pledges on reducing the amount of greenhouse gases.

And the goal is to keep that change on our planet under two degrees Celsius as we go into the next century.

But it's going to require us kind of to work together.

So did you learn the following? Could you pause the video and fill in all the blanks?

Let me do that for you. Global climate change is affected by solar radiation

and the greenhouse effect. It's going to cause human impacts. The greenhouse gases are water vapor

Carbon dioxide is the big one. Methane, nitrous oxide, CFCs.

Remember the source of these greenhouse gases is natural and

Anthropogenic. And so to reduce that we're signing treaties

like the Kyoto protocol and the Paris agreement.

So that's global climate change, and I hope that was helpful.