Lecture 11

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14 Feb 2011

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November 27, 2007
To survive in the world we have transformed, we must learn to think in a new way. As never
before, the future of each depends on the good of all.”
This is the last lecture of the year. Your exam I think is on December 11th. It will be a 3 hour
exam but probably about 1 hour more than you need. The structure will be similar to the mid-
term (short answers and multiple choice). I tried to be more specific this time. You will have
questions from both the lectures and the tutorials. Some of the hardest questions were from
tutorials. So do your readings and your tutorials. There are 2 readings for the tutorial this week
which are listed on the intranet. Make sure to quiz him and read the information. Think about
what is going on there. Is the exam cumulative? No, it is from October onwards. (If you didn’t
write the exam then it will be cumulative so study previous material.)
S:The second ½ isn’t as much detailed so how do you study for that? This is more general
this ½?
P:It wasn’t all numbers but there was a reasonable number. This time I will have to ask
about concepts and general principals. That is what I will quiz you on. There are some numbers
and I tried to point them out to you. Remember the short answers are almost all on concepts so
same deal.
S:Rollover for tutorial so there was one that wasn’t tested on so will it be tested this time?
P:Yes, remember and study it. Those concepts will be included from that tutorial. There
will be office hours during our break as well. Next Monday I will be there from 11:00 -> 12:00.
On Monday the 10th I have a meeting so I won’t be there then. I will be there on Wednesday say
about 11:00 -> 12:00 (normally it is 10:00).
We will talk a little bit about dealing with the threat of global change. How do we deal with it?
We will talk about the process and the potential benefits or how the world is trying to deal with
it. We will talk about how the world dealt with the destruction of the ozone layer. The second
portion we will talk about mitigation and adaptation techniques.
Ozone Depletion
Think about this last 3 months or so the picture I painted is a sobering one. Over the years
history has seen an enormous climatic change. It is resilient and has taken a hit by meteorites
etc. It recovers after time. The dinosaurs left and vertebrates came in. Over the last 10,000
years there has been relatively stability in the system, more over the last 600,000 with a few
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blips. You get the impression that the atmosphere is sensitive. Our effort to reduce the nature
and insult hasn’t been particularly encouraging but there is hope. Only when something terrible
happens we think about making a change.
Dealing with the threat of global change:
The good portion is in the stratosphere and that ozone layer made of this molecule prevents UV
radiation from penetrating to the surface of the earth and causing negative effects. The negative
effects of course are cancer. There are many types of cancers some are malignant and some are
not. I have a red haired friend and he is very susceptible to damage and he has some cancer
taken off of his face a few times. In addition cortical cataracts (lenses in your eyes are damaged)
and that is only for humans and a few other animals.
The other things, plants, we know that plankton may be severely affected by radiation in the
marine environment.
Finally your regular plants have interactions with bacteria and are very susceptible to UV
So all these factors indicate they are bad. So this layer is very thin, about 3 mm thick if you
condense it. There is really nothing there but there is enough to prevent biologically damaging
UV radiation from reaching us.
In 1928 there was an engineer, they have an odd way of looking at things, and he develops a
compound called chlorinated fluorinated carbons. Think of a methane molecule and substitute
chlorine and fluorine on it you create something incredibly stable. It is non reactive, it is inert. It
is inert at the surface of the earth. Apparently a guy called James Lovelock (The Guyat
Principle) developed CFC’s. So he develops a device in the early 70’s to measure this stuff. He
calculates and finds out that it is all there and it hasn’t gone anywhere. So you can account for
all the CFC’s in the atmosphere and it is still there. What happens to the stuff? So why? How
does this stuff work and what is its ultimate fate? In 1974 in California a professor asked what
happens to it (name is Sherwood). He is doing a post-graduate degree. They propose that this
stuff (CFC’s) float up and hit the stratosphere and the intense radiation of the sun that doesn’t hit
the earth breaks it apart. Free chlorine will destroy this molecule and it acts as a catalyst and it
goes round and round. The hypotheses are that the chlorine in CFC’s will destroy the ozone
layer and then we get the brunt of the sun’s rays.
Measurement of the Ozone Layer
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You can see it drops down. This is in terms of ‘Dobson units’ which are determined by a
satellite called TOMS. In 1976 the US Academy of Sciences says we have a problem and they
conclude there is good evidence that the ozone depletion hypotheses are credible. A number of
countries move to ban ozone from aerosol cans. It says ‘refrigerants on it. U.S., Sweden,
Norway, and Canada move to ban it and this is the first step to have a comprehensive regulation
policy. Then things start to slow and Regan is elected to office in the States.Reganomics is
related to Fascism is what they said. You have a slowing and a combination of political factors
i.e. administration and plus resistance from companies that produce the products. They slow the
implementation of the regulations. In addition some of the scientists re-do the calculations and
they were party wrong so they argued against it. The ban is eventually rejected. It continues to
be used to clean off circuit boards, refrigerants, and so on. By 1986 levels are almost the same as
they were in 1976 when they were starting to be banned. You see the system do a flip because
there is vested interest. Just like Exxon oil. DuPont Corporation, who makes it, started to
explore other alternatives and in 1980 they closed down research into alternatives to CFC’s. The
Chairman of the Board of DuPont said that the ozone depletion theory is a load of rubbish and he
is paid to say that. 1983 finally Regan find the Environmental Protection Agency (EPA) is
responsible for executing the regulations, the administrator is replaced. This is critical.
Then finally they find the hole in the ozone layer was discovered in 1985. It is huge. Just last
year it hit its largest amount of something like 27.56 million square kilometers (land mass in
Canada is 10 million). It scared the heck out of everyone. If you ever go to Australia, in the
summer they tell you the UV index. I went to Canberra in the summer and they regularly have
ozone levels of 8 and in Queensland it goes up to 12 times so it isn’t a good idea to be out in the
In 1985 20 nations sign the Vienna Convention to have regulations on ozone depleting
substances. 1987 the Montreal protocol was signed and 43 nations signed on (good exam
question). That protocol starts to limit the use of CFC’s. The participants agree to freeze the
production of CFC’s and reduce production by 50% by 1999. However, because a series of
scientific expeditions get the hard facts in Antarctica, 3 years later in 1990 the protocol was
strengthened and the participants agreed to a phase out entirely of CFC’s. So you can see how
they addressed the problem. So it is potentially doable. The problem will disappear in your
lifetime all things be equal but not mine. By the year 2024 so you will be about 35 there will
detectable reduction. By 2068 ozone levels will recover to about 1980 levels, it doesn’t mean it
comes to baseline.
You can see that under this threat which was significant the world made the right choices. It was
in everyone’s self interest to make a change for the better. The question is given this much more
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