Thanks Chuck!
So I am going to...
I am going to put on my
Scientific Assessment
Panel hat for this talk,
and I am going to do
so because I think
there is actually a little
bit of a debt of gratitude
that needs to be extended
to the Nimbus community
and the NASA community in
general... and NOAA too,
I don't want to
exclude NOAA,
and I will get to that
point at the end.
I think I will make a very
well, not quite a
scientific point,
but a point that I think
is quite fair at the end.
First I am going to give
you a short history;
many of you know Nimbus-4
was launched in 1970,
with the BUV instrument.
I am going to talk about the
Ozone instruments in particular
because I am going
to be coming back
to the scientific assessment
and the Montreal Protocol.
And so BUV was one of
the fundamental ozone
measurement instruments
in the early years.
Now, there were other
instruments measuring
temperatures in
the stratosphere;
Bill has already talked
about that a little bit.
There were instruments
on Nimbus-7, like LIMS;
Jack talked about
the LIMS instrument,
but I am going to focus
on ozone in particular.
So the profound...
the really interesting
thing is in 1974
Mario Molina and Sherry Rowland
published a paper in
which they identified
chlorofluorocarbons as
ozone depleting substances.
We all remember CFCs.
CFCs, chlorine,
fluorine and carbon.
CFCs are very stable.
Molecules; they're
wonderful molecules
as refrigerants, as solvents.
They have just... they have
propellants in hairspray.
I think a lot of us
still remember that,
I think almost all of
us maybe I would say.
And so that was...
this was a very, very
powerful study
that came out,
and when it first came out
it was attacked quite a bit.
There was a lot of
contentiousness from industry,
from people who were
skeptical about
whether CFCs could
actually do something
to the stratospheric
ozone layer.
Of course we all
understand that
stratospheric ozone,
ozone screens,
ultraviolet radiation.
So in 1978 Nimbus-7
was launched.
There had been a lot of
information accumulated
about ozone depletion
by that time.
In 1981 negotiations
began on an agreement
to actually protect
the ozone layer.
So that was very early on.
And there are a few
people in this audience
who were actually working
on the assessments
that were looking at the impact
and I've kind of blown
past it really quickly, but
the supersonic transports
and the shuttle
putting chlorine and
oxygen into the atmosphere,
but in particular CFCs,
again, attacking
the ozone layer.
So in 1985 there was a
real fundamental change
in how we looked at
the ozone layer.
This was the publication
of a study by Joe Farman,
and Brian Gardiner and Jon
Shanklin that showed
that there was very severe
ozone lost over Antarctica.
This really had a
tremendous impact
on the stratosphere community,
because nobody understood
why ozone should be just
on a downward trajectory,
towards zero.
There were a number of
theories that came out.
I was a proponent of one
theory in particular
that unfortunately
turned out to be wrong.
I actually thought it
was a dynamical cause;
it was a lifting circulation
in the lower stratosphere,
it could be
depressing ozone.
And in 1987 there was a
field campaign launched
to actually go look at --
it was the NASA ER-2
and the NASA DC-8,
went down to Antarctica to
look at these processes,
and in one graph
was a graph
produced from the
Harvard Group,
showed very high levels
of chlorine monoxide;
levels that
were well above
what you would project
that just standard
chemistry was going on.
So in one graph they
pretty much proved that;
one, ozone was
going down;
and two, it was
due to chlorine.
And so fundamentally
they demonstrated
that this trend here,
Farman... Farman, Gardiner,
and Shanklin actually
proposed it with CFCs,
but they didn't have...
actually their theory
of it was incorrect.
But new ideas came along
and in fact it turned out
that this was due to
chlorofluorocarbons.
Now, just to give you some
added information here,
those red points
come from Nimbus-7,
you can see here.
And here is three blue...
kind of purplish points,
this come from Nimbus-4,
so you can see...
and these are actually
the lowest values
found in the October average.
Black points are the
October averages over Halley.
The red points and the purple
points are the low values
that are seen over Antarctica
from the satellite image.
Now this trend in
it of itself
is very interesting
to scientists,
but what really had
a tremendous impact
was this first picture,
and many of you wonder, why
is it called the Ozone Hole?
Well, you know...
you try to trace out where the
word actually comes from.
It's very hard to
trace where...
why it's called the Ozone Hole?
Nobody seems to know.
But I am pretty sure
that at the time,
it appeared right after
this figure was published,
and I think it comes about
because that's what
Sherry Rowland from
Molina and Rowland,
that's what he called it,
he said there is a hole
that's formed in
the ozone layer.
So here's these very,
very low values,
here is the... it's false
color image of ozone
and here you can
see Antarctica,
there is South
America, Australia,
there is Africa,
and here's this
very, very low amount.
Now this - here's PK
Bhartia down here,
PK was the one,
he had a huge room Al Fleig
is sitting back here,
Al can probably tell you
how big the room was,
it contained
all the computers
that actually helped to produce
this particular figure,
but this figure had just
an incredible impact
on the community
at that time.
The other thing was... and
I haven't mentioned this
is a lot of people have
said that NASA was...
this Nimbus data was
being thrown now.
In fact it wasn't
being thrown out,
it was being flagged,
and it was flagged
because it was well below
these red points were
well below the climatology
that you expected
over Antarctica.
And so, naturally, what's a
natural scientific inclination,
you start to get
funny values,
your first impression
is, oh my God,
what have I done wrong?
You know, why is our
instrument failing?
In this particular case
they were looking into this,
PK was; and actually
came to the conclusion
that in fact the instrument
was working fine,
and he actually put in,
in late 1984 the early
1985 he put in a...
submitted a paper to the
IAGA Meeting in Prague
that was in August of 1985
that was going to show
these extremely low
values over Antarctica,
but the British Antarctic
Survey Publication
appeared a couple of
months before that,
and actually the BAS guys
have been looking at the
problem for about a year.
So we have the... there
is the urban legend,
the NASA was throwing data
into the bit bucket,
it's absolutely
an urban legend.
And actually a story,
the real story is
actually better
that the Nimbus
people, PK and others,
were looking at the data
carefully before they rushed out
and put something
into press.
So don't believe
the urban legend,
the true story is actually
a better scientific story.
Okay, so these particular..
this particular image
that you see over here,
appeared in this three volume
set 'Atmospheric Ozone 1985',
this is a pretty
good-sized book,
it's about... I don't know,
3-4 inches thick, 3 volumes.
This book, with
these images in it,
this was the science that
formed the basis for the
1987 Montreal Protocol.
A lot of people
say, the Ozone Hole,
that's what led to the
Montreal Protocol.
Well, all the
negotiators had that
in the backs of their heads
but they are actually
looking at this volume,
this huge scientific
assessment,
the work of hundreds
of scientists
from around the world.
In fact there is another
one that's coming out,
it will be appearing
in January 1 of 2015,
and there is a number of
people here gathered
who are still working
on these assessments.
So now this is where we
are now with the Ozone Hole,
and actually it
was plunging
and in the 1990s it
kind of hit bottom,
and you know,
if you kind of look at it
here maybe with a...
little bit of a
filter in your eyes
it maybe looks like
there is some hints
that things are
getting better.
Here is what the
picture look like
in 1979 of the Ozone Hole,
that's an October average,
and this is the average
from last October.
Now we're in the
middle of the ozone hole
season right now,
these are actually a
series of pictures,
here's one of the
old BUV pictures,
you didn't get any
back-scattered sunlight,
so that's a data
void right there,
but you could see these low
values and how it got worse.
And now there
is maybe a hint
that it's not as bad as
it was in say 2001.
So there is some hints now
that things are getting better,
but here we are in
September 2014
and they're still a very,
very big ozone hole
over Antarctica, okay?
Why is that? That's because
chlorofluorocarbons,
these gases,
the CFCs, have very
long life times.
Lifetime of CFC-11
is about 55 years.
The lifetime of CFC-12
is about a 102 years.
Okay?
Now,
you can start that?
I am going to show you
a little movie here
of what would have happened;
this is actually
the model
that Jack Kane worked
on back in the day,
this is the evolution of
that, to a modern model.
On this top left picture it
shows the levels of chlorine
and bromine
in the stratosphere.
So you think about this,
this is the level of chlorine
and bromine available
for destroying ozone.
Here, you can see
a little red point,
it's going to follow
this trajectory,
and in the other
model simulation
it keeps going up
and up and up.
I call that the
world avoided here,
and you can see very, very
low values over there;
it's going through
each month.
This is global
total ozone,
so just to average
over the entire thing.
You can see that ozone is
going down as chlorine goes up,
with this blank
point there
and that blank point there.
And you can actually
see the difference
between the ozone simulation
here, which is this,
the ozone simulation
here, which is that.
And if actually
you look up here,
this is now at 2030, you
can see there is a...
every year an Arctic
ozone hole forms.
And so as you go through
here you can see
as chlorine continues
to climb up
from the model simulation here,
ozone continues
to go down
and the global amount goes
down and down and down,
the normal amount is up,
the global is about 300,
and you can just
see the values,
as chlorine
continues to go up
how ozone continues
to plunge downward.
Now, this is a
modern model.
This model has the chemistry
impacts the radiation,
there are greenhouse gases
that are going up
in this model,
the radiation changes
temperatures,
temperatures change
the wind patterns,
wind patterns blow things
around differently.
This is a complete
interactive modern model.
So you can see by the
year 2065 globally
we're now less than
a 100 Dobson units,
so about two-thirds
of the ozone layer
is gone by the end of
the simulation here.
And this is because of
the Montreal Protocol,
the ozone-depleting
substance went up
and they are slowly falling off
because CFCs are very
long-lived gases.
If nothing had been done,
there had been no
Montreal Protocol
and things had been
going up and up and up,
by the end of the simulation
ozone is virtually gone,
and of course UV levels,
you can take this
ozone and compute UV.
UV indexes have tripled
around the world.
So we get... typically
in the Washington, D.C. area
we get a UV index of
something like 12 during July,
fairly high UV index,
and in here it would be
something like 36 or so,
36, 40.
So you would have
huge UV levels.
Now, one thing I will
mention about this,
so UV levels, you're going
to get a fast sunburn,
but there are other
things that happen.
For example, skin cancers
are directly proportional
to your cumulative
UV exposure;
melanoma is
related to acute,
the blistering kinds
of burns that you get.
More importantly,
in the simulation
what you find though is
crop yields plummet.
You get huge damages
to crop yields,
and actually by the
year of about 2015,
which right here,
here is 2010,
so 2015 is about here.
Chlorine has
gone up a lot.
Ozone has declined.
There is considerable crop
damage by the year 2015,
considerable crop damage.
Now, right now
in this world
we produce enough food
to feed the planet,
so mainly, okay?
If you can imagine
something like a 15-20%
loss of crops
by this year,
if we had done nothing
for chlorofluorocarbons,
you can imagine what
would have happened
in terms of just
feeding the planet,
and I will come back to
that in a little while.
So now to go on, come
back to the history here;
negotiations, 1985, I
didn't mention this,
but the Vienna Convention
is the agreement
that called for cooperation,
research and data exchange,
but it didn't oppose...
impose any obligations.
The ozone hole
was discovered,
the Montreal
Protocol was adopted.
It established control
measures on CFCs.
It didn't actually stop
the production of CFCs;
it just controlled the
production of CFCs.
But as further
science comes along,
we had more of these assessments
that I have talked about,
they kept strengthening
the regulation.
George Bush,
Sr., President Bush, Sr.
actually banned the
production of CFCs
in the United States
in the early 1990s.
And so now, after 2010
there is no allowed
production of CFCs or
halons in the world.
Every country of the
world has now signed on
to the MontrŽal Protocol.
It's the only
agreement in the world
that has 100% compliance,
and this includes
name the country,
Andorra, the little tiny
countries of Europe,
they all signed this.
Even the... we call
the Axis of Evil,
has signed this agreement.
So it's an universally
agreed-upon agreement
to regulate
chlorofluorocarbons.
Now this is another plot
that I am going to show.
This is the SBUV data,
and so this is from...
it goes back to
the BUV instrument
and then there is the SBUV,
got to 1993 on Nimbus-7
and then this is
the continuation on
various NOAA satellites
in fact there is
a little melding
of some of the satellites,
and the black line is
the smooth version.
This is average 60
South to 60 North,
so it doesn't include
polar losses.
But you can see that ozone was
going down through the 90s,
this big low here is
due to Mount Pinatubo,
turns out volcanoes
can actually lead
to enhanced ozone destruction.
The particles that are
formed by sulphate aerosols
in the stratosphere,
can enhance ozone loss,
and so it appears that
over the last few years,
if you kind of look here
from this period on,
it looks like there may
be a slow upward drift,
and I am going to
show actually a plot
that appeared... I talked
about this new assessment
that comes out
2015 or January 1,
but we already
have released
what's called the assessment
for decision-makers,
this is the scientific...
the short scientific document
that does to the
parties themselves
and will be discussed in
Paris in about a month.
And this actually
you can see, this
is 1979 to 1997.
This is a trend as a
function of altitude,
this is the northern
hemisphere,
mid-latitude, so
straight above us here.
You can see from
1979 to 1997 ozone
was decreasing in
the upper stratosphere,
and now if you look from
over this 2000
to 2013 period,
you can actually see
that ozone is going up.
These are uncertainties,
this tells you
that it's actually
different from zero.
So we can now in the upper
stratosphere discern
that ozone is increasing.
So ozone depleting
substances are on the decline,
we measure those
all over the place,
and now we can see that
from an instrument
like the BUV -- SBUV series
that ozone is in fact
starting to increase in
the upper stratosphere.
Now one thing
I don't mention here
is part of this is due to the
decline of ozone depleting
substances likes CFCs,
about half of it is
due to climate gases,
in particular CO2.
CO2 cools off
the upper stratosphere
and that actually slows
down the ozone mass process.
So about half of this
increase is due to CFCs
and about half of the increase
is due to climate gases.
So just a quick summary:
the observations from
Nimbus-4 and Nimbus-7
had this
tremendous impact,
I think on the atmospheric
science community.
Although the ozone hole
wasn't the driver behind
that huge document,
I am talking about,
was the real
driver behind the
signing of the
Montreal Protocol.
The ozone hole
sat in the back
of all of these
negotiators heads.
You can talk to them,
I go to these
meetings twice a year
and you talk
to these folks,
and even today those ozone
hole pictures still have
a dramatic impact on
the negotiators,
it gives them the
emphasis to continue
to go forward
with regulations.
And as I already
mentioned,
ozone depleting
substances,
they are declining,
we have lots of
observations of this,
and the ozone layer is beginning
to show signs of recovery.
And now I am going
to... one last thing,
it was negotiated
in 1987 ratified
by the U.S. Senate in 1988,
and I just...
there is a point
Montreal Protocol is a...
this is a famous
Liberal who said this,
"The Montreal Protocol is
a model of cooperation.
It is a product of
the recognition
and international
consensus that
ozone depletion is
a global problem,
both in terms of
its causes and effects.
It is a monumental
achievement."
This is one of
the famous Liberals
that have been President
of our country,
Ronald Reagan.
[Laughter]
Now I am going to
add one thought here,
and this is I think
in... you know,
I was... I did a lot of
work on the Nimbus data
over the years as a
scientist here at Goddard,
and for that I am actually
proud and grateful.
But I want to add a
little thought here.
I mentioned that if
the Montreal Protocol
had not been signed
or signed, agreed to,
signed by all the
nations of the world,
we'd be in a real
mess right now.
There would be tremendous
food shortages.
The human impact would
be rather modest,
but the tremendous
huge shortages..
when in fact if you go back
to what happened in Tunisia
a few years back, they
started having riots
over the increase
of food prices.
This is the first thing
that would have happened.
As food shortages
began, food riots
and political
instability would begin.
They don't give out medals
for solving problems
that didn't appear.
So no scientist is going to
get a medal for all of this.
Although Mario Molina
and Sherry Rowland did
get the Nobel Prize,
but for all the people
who supported Nimbus,
who made these
early observations
and allow us to understand
what happened to ozone,
the continued
work on that,
nobody is
going to get credit
for having avoided
these food riots,
the emergence
of politicians
who would exploit this for
their own political purposes
and leading to a lot of
instability around the world.
Nobody is going to get credit
for having stopped that stuff.
But, I think NASA,
the Nimbus program
and the continuing
work on that,
the scientists
can take a lot of
the engineers behind it,
all the people who
designed these satellites
and worked on,
can take a lot of,
I think quite
pride in the world
that was avoided by
massive ozone losses.
So with that I will close,
and thank you to all of
you who worked on that.
[Applause]