Time transcripts of G2015-023_Ozone_TedTalk_youtube_hq

[00:00:00:000]	[chimes] 

[00:00:04:010]	[chimes fade out] [concerned driving music starts] 

[00:00:08:020]	[music fades out] >>Paul: I'm going to tell

[00:00:12:020]	a real scientific and I think public policy success story,

[00:00:16:040]	and it's about the ozone layer. You can see the globe

[00:00:20:060]	here. We divide the atmosphere into a variety of layers.

[00:00:24:060]	The troposphere is the lowest layer, it's where all of our weather occurs.

[00:00:28:080]	The stratosphere is the next layer up, and that's what I'm going to really focus on, because that's

[00:00:32:080]	where most of our atmospheric ozone is located.

[00:00:36:090]	Now ozone is critical in our atmosphere because it screens ultraviolet radiation.

[00:00:40:090]	Ultraviolet radiation, these are energetic solar

[00:00:44:110]	photons, there are, they are strong enough

[00:00:48:110]	to break the bonds of biologically active molecules, like DNA

[00:00:52:120]	for example. So, if you decrease the amount of ozone,

[00:00:56:140]	which is screening this UV radiation,

[00:01:00:140]	you get more at the surface, and what that'll do is that you get,

[00:01:04:150]	you sunburn a little more quickly. For example a person like me,

[00:01:08:160]	I'm out for about 15 minutes and I'll get a sunburn. But it does a lot of other things.

[00:01:12:190]	It impacts crops, it can cause cataracts. There's a famous study

[00:01:16:200]	of water men out here on the Chesapeake Bay in which they found

[00:01:20:210]	that their amount of time on the bay was proportional

[00:01:24:230]	to the cataracts that they got. The longer you were out there, the more cataracts you got.

[00:01:28:240]	But that's extended exposure over the years. So ozone is really

[00:01:32:260]	a critical gas in our atmosphere.

[00:01:36:260]	In 1974, these two gentleman on the right, this is 

[00:01:40:270]	Sherry Rowland, and this is Mario Molina. They proposed that there were

[00:01:44:280]	a class of gases being emitted into our atmosphere that

[00:01:48:290]	could destroy the ozone layer. These are chlorofluorocarbons, or CFCs.

[00:01:53:000]	So, they proposed this, and it was

[00:01:57:010]	quite controversial at the time. They took a lot of heat 

[00:02:01:030]	because this chlorofluorocarbon industry, chemical industry,

[00:02:05:040]	was used in a variety of different kinds of products.

[00:02:09:050]	You can see some of these, many of us remember, it used to be used as a propellant

[00:02:13:060]	for hairspray, and deodorants. It was

[00:02:17:070]	used to make foam products, like these cups you would get

[00:02:21:070]	from McDonalds or other companies. It was used,

[00:02:25:080]	CFCs were used in air conditioning and in car air conditioners.

[00:02:29:080]	It was also, there's another kind of gas called a halon.

[00:02:33:090]	Halons are used in fire extinguishers, they contain bromine. They can also

[00:02:37:090]	destroy ozone. So this is proposed in 1974,

[00:02:41:100]	and there was a huge amount of energy and effort that was going in

[00:02:45:120]	the late 70s and early 80s to see what the impact

[00:02:49:130]	is on ozone, to measure ozone and these gases in particular.

[00:02:53:130]	Now, in 1985, there was a publication

[00:02:57:140]	of a paper on ozone down over Antarctica.

[00:03:01:150]	And these three gentleman here, this is Joe Farman,

[00:03:05:160]	Brian Gardiner, and John Shanklin. They're standing in

[00:03:09:160]	front of an instrument that measures the total amount of ozone between the surface and space.

[00:03:13:170]	And they published their data. And you can see it here,

[00:03:17:190]	this is a measurement, this is the total amount of ozone between

[00:03:21:200]	the surface and space over the station. It's Halley Station down in Antarctica.

[00:03:25:210]	And what that shows is that the level of ozone

[00:03:29:230]	was dropping and it was dropping really fast. Okay. 

[00:03:33:240]	It was an amazing study that they published, and the quality of these 

[00:03:37:250]	data are such that there was no dispute to this. Ozone 

[00:03:41:270]	was going down, and it was going down fast. This was a real shock

[00:03:45:280]	to the atmospheric community, when this paper was published.

[00:03:49:290]	Shortly thereafter, and this was in the,

[00:03:53:300]	in 1985 also, a scientist at the NASA Goddard

[00:03:58:000]	Space Flight Center P.K. Bhartia made an image

[00:04:02:010]	of what this ozone looked like over Antarctica.

[00:04:06:020]	And so you can see Antarctica here in the center, South America, Africa,

[00:04:10:020]	Australia, and here in the middle is this very low ozone area,

[00:04:14:040]	these red colors and yellows that you see here indicate very low ozone.

[00:04:18:040]	And it was dubbed "the Antarctic ozone hole".

[00:04:22:060]	So ozone was going down fast, and it was a huge region. 

[00:04:26:070]	This is a very large region, comparable to, this continent of

[00:04:30:080]	Antarctica is a large area, so there's a large depletion over

[00:04:34:090]	a large area. And we didn't actually understand what was going on at the time.

[00:04:38:100]	But within a couple of years, we figured out it was actually due to these

[00:04:42:110]	chlorofluorocarbons and halons.

[00:04:46:120]	

[00:04:50:130]	So there was a lot of consternation about this. What are we going to do? How can we

[00:04:54:170]	stop it? What are other measurements can we make? So the rising 

[00:04:58:180]	concern about the problem amongst the nations of the world,

[00:05:02:190]	there was already discussion about, should we get together and create an agreement?

[00:05:06:210]	And in fact after a couple years, they did create an agreement.

[00:05:10:220]	This is an agreement called

[00:05:14:240]	the Montreal Protocol. 

[00:05:18:250]	These are, this is a, this shows a meeting of the parties to the Montreal Protocol.

[00:05:22:260]	took place in Doha, in the Saudi Arabia peninsula

[00:05:26:260]	And here you can see the Montreal Protocol had a series of

[00:05:30:270]	agreements the initial one, and they were added on to, further

[00:05:34:290]	strengthening regulations of these chlorofluorocarbons. So eventually,

[00:05:39:000]	the production of chlorofluorocarbons and halons

[00:05:43:020]	was fully agreed to. Now, you can see the nations of the world, 

[00:05:47:030]	there are little signs here. Here you can see, this is me sitting

[00:05:51:040]	way in the back of this meeting. Even though

[00:05:55:060]	the scientists, we bring them all the information, we're always put at the back of

[00:05:59:070]	the meeting. When they need us, they'll call on us, but we sit in the back and listen

[00:06:03:080]	 to all the discussions. And mostly these discussions are about countries'

[00:06:07:100]	ability to maybe use a CFC for a short time. There are a lot of different

[00:06:11:110]	things going on in these meetings.

[00:06:15:130]	Okay. So now what's happened with ozone. Well first of all

[00:06:19:140]	let me talk about chlorine. So chlorine,

[00:06:23:150]	it was going up and up and up through the 1960s, 1970s, 1980s.

[00:06:27:160]	These are a combination of all the CFCs and halons. And then the

[00:06:31:170]	Montreal Protocol was signed here in 1987, and

[00:06:35:190]	slowly those regulations began to take hold, and in fact

[00:06:39:200]	the projection is that these

[00:06:43:210]	ozone-depleting substances are going to decline with time. Now this is going to take a long time,

[00:06:47:230]	because CFCs, these chlorofluorocarbons have long lifetimes. 

[00:06:51:240]	For example, CFC 11 has a lifetime of about

[00:06:55:250]	52 years. CFC 12, which was used in

[00:06:59:270]	your car air conditioners, has a lifetime of over 100 years.

[00:07:03:280]	So it's going to take a long time, even though the production and emission

[00:07:07:290]	of these gases has been regulated, it's going to take a long time for them

[00:07:12:020]	to come out of our atmosphere.

[00:07:16:020]	So what's happening with ozone now? So this is showing

[00:07:20:040]	this is in percentage, the change of ozone over time in percentage.

[00:07:24:040]	You can see the observations as you go into the 80s. You can see

[00:07:28:060]	that ozone was going down, the CFCs were increasing,

[00:07:32:080]	the Montreal Protocol is signed here. Pretty soon the chlorine 

[00:07:36:080]	has started to decrease, and you can almost,

[00:07:40:090]	there's a Mt. Pinatubo effect right here, but you can almost see that ozone isn't going

[00:07:44:100]	down anymore, and maybe there's a hint that things are starting to go

[00:07:48:110]	up. We can't say that, as scientists we can't that's true yet, 

[00:07:52:120]	but I think we're getting to the point, within the next few years, I think we'll actually 

[00:07:56:120]	be able to say statistically that ozone is increasing 

[00:08:00:140]	in our atmosphere. Let's keep our fingers crossed. 

[00:08:04:150]	Now, the other way of looking at this is we can use a model 

[00:08:08:160]	to take a look at what would have happened to ozone if we'd done nothing.

[00:08:12:170]	So I'm going to show you a little model study here. And on the top left, I'm going to show you

[00:08:16:170]	the expected world. And this is with the Montreal Protocol,

[00:08:20:180]	CFCs are going to decline. Over here is what we call "the world avoided".

[00:08:24:200]	And this is chlorine going up. If you look on the picture,

[00:08:28:200]	you can see the amount of chlorine in the expected world and the amount of chlorine

[00:08:32:220]	in the world avoided. So you can see here it's 4.5, there it's

[00:08:36:220]	already a little bit higher because of the Montreal Protocol,

[00:08:40:230]	this is because of the Montreal Protocol, that's without one. And you can see this flying by 

[00:08:44:250]	fairly quickly, as you can see the date on the right, you can see the ozone hole appearing

[00:08:48:260]	every year. Chlorine continues to go up in this

[00:08:52:270]	world avoided, and now you can actually see it peaked down at about 4

[00:08:56:280]	and it's in a slow decline as we're out to 2022, 24.

[00:09:00:290]	If you look here at this world avoided you can now start seeing a little ozone 

[00:09:05:000]	hole deep low values appearing over the Arctic. 

[00:09:09:010]	And you see the very very large ozone loss 

[00:09:13:020]	in over the Antarctic region. If you look at the expected world,

[00:09:17:030]	you don't see any of those things. And in fact this chlorine continues to increase,

[00:09:21:040]	you can see ozone going down now in the tropics 

[00:09:25:050]	and in the subtropics. So you can see that here you're dominated by reds and

[00:09:29:060]	oranges, the higher ozone levels. In the world avoided, you can see

[00:09:33:080]	that ozone is declining and declining and declining. 

[00:09:37:080]	Now, this is about 40 to 50 times, by the time you get

[00:09:41:090]	out to 2065 here, this 40 to 50 times

[00:09:45:110]	the natural level of chlorine in our atmosphere. Chlorine and bromine

[00:09:49:110]	combined. And this has gone down, it about needs to go down to

[00:09:53:120]	about 1.2, this is about halfway there. But you can see

[00:09:57:140]	the difference in ozone. 65 per-, or excuse me, about two 

[00:10:01:140]	thirds of the ozone layer is destroyed if there had been no 

[00:10:05:150]	Montreal Protocol, if nothing had been done. Okay. Now what does that mean? 

[00:10:09:170]	That means huge impacts on crops. 

[00:10:13:180]	For somebody like me, I mentioned that if I go outside, 15 minutes I'll get a

[00:10:17:190]	perceptible burn. In that world it's 5 minutes. Okay.

[00:10:21:200]	So you go out and you walk for a quarter of a mile, you would get

[00:10:25:210]	a perceptible sunburn. So, this is an 

[00:10:29:220]	incredibly bad world, we don't want to live in that world. This is the one that

[00:10:33:240]	we expect. Now, we can do, 

[00:10:37:250]	as I've already shown, we can do these projections of where ozone is going.

[00:10:41:260]	Here we can see the observations, this shows a model projection, 

[00:10:45:270]	and now I put two model projections on here. The lower one is

[00:10:49:280]	 a world in which both ozone-depleting substances,

[00:10:53:290]	it has a Montreal Protocol in it, they've been regulated and so ozone is

[00:10:58:000]	going up. But in one, greenhouse gases are regulated.

[00:11:02:010]	In the other, greenhouses gases continue to go up.

[00:11:06:020]	And in fact, ozone continues to go up. So,

[00:11:10:030]	the net impact of increasing greenhouse gases is that the ozone layer begins to pile

[00:11:14:040]	up lots of ozone. So instead of a depleted ozone world, we're going

[00:11:18:050]	to go to an ozone world where there's probably too much ozone.

[00:11:22:060]	Now what does that mean for the environment? I actually don't know. I don't think we 

[00:11:26:070]	know as scientists what's going to happen there.

[00:11:30:080]	So let me say another word about

[00:11:34:080]	what happened. This is, I love this picture,

[00:11:38:090]	I owned a 1967 Ford mustang fastback. It was

[00:11:42:100]	a hot car. I love this car. It has a CFC air conditioner in it.

[00:11:46:120]	So I was using CFC-12 in that

[00:11:50:120]	particular air conditioner. Here is a Tesla, a modern Tesla.

[00:11:54:140]	It uses a replacement compound called an HFC,

[00:11:58:140]	in fact HFC-134a. And in fact in all your cars right now, 

[00:12:02:160]	you have that particular refrigerant in your

[00:12:06:170]	car air conditioner. So this is the compound that replaced the CFCs. 

[00:12:10:170]	Now the beauty of this is this is a hydrogen, a fluorine, and a carbon.

[00:12:14:190]	It doesn't have chlorine, so it doesn't destroy the ozone layer. 

[00:12:18:200]	The problem with HFCs though is they're greenhouse gases.

[00:12:22:200]	The particular HFC 134a is about, 

[00:12:26:210]	pound for pound, it's about 14 hundred times more

[00:12:30:230]	efficient at warming than CO2.

[00:12:34:240]	So you could take one pound of this HFC-134a,

[00:12:38:260]	is equivalent to about 14 hundred pounds of CO2.

[00:12:42:270]	So the replacement compounds for the CFCs

[00:12:46:280]	are greenhouse gases. And the question is, what are we going

[00:12:50:290]	to actually do about these? Now this shows a particular HFC, this is HFC-23.

[00:12:54:290]	You can see these are observations they're increasing with time. Because we

[00:12:59:010]	replaced the CFCs. There are many other HFCs.

[00:13:03:020]	This is the one I talked about, it's in your car air conditioner, 134a.

[00:13:07:030]	This one 32 and 125, these are probably

[00:13:11:040]	in your home air conditioning units. So all these HFCs

[00:13:15:050]	are increasing with time, and these HFCs are all

[00:13:19:070]	powerful greenhouse gases. So, we solved the problem, 

[00:13:23:080]	that is the problem of ozone depletion, but in fact, and in fact those

[00:13:27:090]	CFCs were also powerful greenhouse gases, but we replaced them with compounds 

[00:13:31:110]	that are also powerful greenhouse gases. 

[00:13:35:120]	So you could do a lot for climate if you figured out how

[00:13:39:120]	to take these compounds and replace them with compounds that are both

[00:13:43:130]	friendly to the ozone layer and friendly to climate. And in fact

[00:13:47:130]	there are technological solutions. So that goes back to the Montreal Protocol.

[00:13:51:150]	The Montreal Protocol could in fact take action on these

[00:13:55:150]	HFCs. We don't know that that's going to happen, but it might.

[00:13:59:170]	So let me kind of summarize

[00:14:03:170]	where we've been. So I told you a good story. We got rid of these

[00:14:07:180]	CFCs, they're now regulated, they still exist in various places around the atmosphere,

[00:14:11:190]	but they're slowly declining. That's a great story. In fact, the outcome

[00:14:15:200]	of that would have been an environmental disaster

[00:14:19:220]	if they had kept growing. We used a lot of satellite information

[00:14:23:220]	to take a look at the ozone problem. Most of the observations

[00:14:27:230]	you've seen on this presentation have come from NASA

[00:14:31:250]	satellites, including the Aura satellite that you can see here. 

[00:14:35:260]	Now what does the future hold? Well, the future's in our own hands.

[00:14:39:270]	We have two things we can, you can regulate these compounds,

[00:14:43:280]	and that may happen. But the one thing that we really need to do

[00:14:47:300]	is we need to continue to look at the atmosphere continue to make measurements

[00:14:52:010]	of what's happening to our atmosphere. And that's where satellites like Aura

[00:14:56:020]	and its follow-ons are crucial to knowing where we're going to be in the future. 

[00:15:00:030]	Thank you. [applause]

[00:15:04:040]	[applause dies out] 

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