And I just wanted to mention a few more things about community ecology
before I move onto the final lecture which I've forecasted to you where
I'm going to try to tie everything together through a research story
that I want to tell you about. But before we go to that, I just
want to present one very famous ecological experiment
from your textbook. Because what we're trying to do here
in this lecture is bring together the first set of lectures where we
talked about biogeochemical cycles and productivity which we think of
as the function of ecosystems with the last set of lectures where we
talked about population biology, community structure where we
actually talk about different species and how they interact.
And the structure of the community effects productivity
in biogeochemistry. And these processes in turn feed
back and affect the structure of the community. And this is something
ecologists have known, but it's not easy to demonstrate
this experimentally. So one of the famous experiments
was done by David Tillman of the University of Minnesota because
these are very long-term experiments. And, of course,
it's easier to do these kinds of experiments with plants because they
actually stay put. So he asked the question is the
species diversity of plants in a living community related to the
productivity of that community, and also the resistance and the
resilience of that community to stress? So what he did is he set up
plots. And he went through generations of graduate students
monitoring these over many years. This would be a plot that would
have a single species in the plot. And here's a plot that has 24
different species in the plot. If we mixed them together they were
all indigenous species that would grow there. And he showed first
that the total plant cover here as a percent was a function of the number
of species per plot. So establishing that indeed
productivity, the amount of plant biomass produced was a function of
species diversity. And when you think about this it
makes sense because the more diverse species you have the more likely
they're able to exploit the full suite of resources in the soil and
are probably more resistant to predation. So the more diverse the
plot it has a greater biomass. The next thing he looked at, and
this is in your textbook, was the effect of the biomass to the
resistance to disturbance. So this is a change in biomass one
year before a drought and then to the peak of the drought showing that
this ratio increased with the number of species. And finally the
resilience, that is how long it takes for the community to recover
after it's been stressed, he was also able to show increase as
the number of species increased. So there is a relationship between
community structure, and indeed productivity,
resistance and resilience increase if there is more diversity,
which is, of course, one of the motivators for preserving species
diversity on the planet globally. OK.
Now we're going to try to tie all this together through this story.
Now, going back, many of the slides that I'm going to show you you've
already seen. Parts of this story you've already learned from my
previous lectures, so I'm trying to tie this together
and remind what you know and help you to think about how you can apply
what you know to current issues in global ecology.
So you remember this, our global carbon cycle showing the
photosynthesis of the plants balanced by the respiration of the
plants and the animals. You learned this. And superimposed
on that is our burning of fossil fuels and land use changes,
i.e., cutting down trees increasing CO2 in the atmosphere.
And as we showed last time, I mean in the first set of lectures
that this sudden excavation of this fossil photosynthate is causing a
dramatic increase in CO2 in the atmosphere relative to historical
concentrations of CO2. This is thousands of years before
present. And we're worried about that.
This is all reminding you, getting you in the train of thought here.
We're worried about that because there's good evidence that these
increases in CO2 are already increasing the temperature of the
planet. This is average temperature over the last thousand years.
And if it isn't already there is certainty that it will in
the very near future. So let's look here in the ocean,
my favorite ecosystem, where the phytoplankton,
that you know all about now, play a critical role in drawing CO2
out of the atmosphere. And this draw down is referred to
as the ìbiological pumpî of the oceans. And we talked about this
very briefly. Here's the phytoplankton community
photosynthesizing, drawing CO2 into the surface ocean.
And then because of the food web, that you've learned all about, most
of this phytoplankton productivity is eaten by zooplankton and by fish
going through the marine food web. As it's eaten they are respiring
and CO2 is released and it goes right out of the system.
So CO2 in, CO2 out. But some of that carbon, some of that
photosynthetic product finds its way to the deep ocean through fecal
pellets of zooplankton, through aggregates of dead cells,
through just basic mucus that fluffs off of jellyfish.
It's all carbon that came from photosynthesis,
but some of it settles down to the deep ocean where it's chewed upon.
Now, here is where all those deep consumers that I showed you in the
DVDs last time are. There are fish and squid and
jellyfish in the deep oceans that feed on this carbon that rains down,
because there is no photosynthesis down there, and bacteria that then
regenerates that organic carbon into CO2. So this functions as a pump.
And the concentration of carbon dioxide in the deep ocean is very
high if you look at a depth profile of CO2.
This is depth and this is CO2. And at the surface, of course,
it's in equilibrium with the atmosphere. And it's very high in
the deep ocean because at low temperatures and pressures it can
hold. So this is a huge reservoir of CO2, so much that if you did a
thought experiment and you killed all the life in the oceans and just
shut off this biological pump and then you let the oceans mix all the
way to the bottom, which they won't do,
but this is just a thought experiment.
And you let that all equilibrate with the atmosphere,
all of that CO2, the concentration in the atmosphere would double to
triple what it is today. That's how much CO2 is in the deep
ocean. And so this is a natural function of the ocean ecosystem,
is to maintain this pump and maintain this gradient of CO2.
So this you also learned, remember? That the oceans are not
this homogeneous soup of phytoplankton,
but there are areas of very high phytoplankton biomass and
productivity and low biomass and medium in the green here.
And we talked about nutrient limitation of that primary
production, which is the availability of nutrients.
And what I told you was that the sort of standard understanding of
this system was that nitrogen and phosphorus were the primary limiting
nutrients, this is all review for your final exam,
in aquatic ecosystems. But I told you that I was going to
tell you in the last lecture that there was more to it than that.
And there is indeed much more to it than that.
So for years we thought that nitrogen and phosphorus were the
nutrients that were regulating this differential productivity,
but we knew that something was wrong with our understanding.
Because these satellite images, which I just showed you, of the
distribution of productivity showed this distribution.
But if you took a simulation model and modeled the global productivity
based on the availability of nitrogen and phosphorus to the
phytoplankton this is what the model showed.
They said this is what the ocean should look like,
not that. There should be much more productivity here in the equator and
down here in the Southern Ocean than there actually is.
And, in fact, people wrote papers why isn't the equator greener?
And they had all these different hypothesis for why that might be,
a lot of them having to do with grazing with the food web.
Well, it turns out that iron is a really important limiting factor in
the ocean. And this is a story that has just unfolded in the last 15
years. And I'm not telling you in exactly the order that it unfolded,
but more or less in the order that it unfolded. A fellow named John
Martin who is an oceanographer out at Moss Landing Marine Labs had been
studying iron for quite a long time in the ocean.
And he had a hypothesis that iron was limiting. But most people
wouldn't believe him because most people, when they went out to
measure iron in the oceans, got very high concentrations.
So they said how could that be limiting? Well,
it turned out that most people were measuring contamination in their
iron samples. And if any of you have ever been on a marine ship,
if you look around the deck you notice there is always rust.
They are constantly painting marine ships, right, because the seawater
is very corrosive. And so there is rust everywhere.
And it turns out that you have to be heroically clean in order to
measure the concentration of iron in seawater. And John Martin and his
group realized this and went out and developed these techniques to
collect the sample and to have it never see air before it went into
the sample bottle. And they acid washed the sample
bottles through this process which takes weeks and weeks and weeks.
I mean you had to really believe that iron was limiting in order to
go through all this agony to measure the level. So his group was able to
measure really low levels of iron in seawater, but still they weren't
able to convince people because this was such a totally different way of
thinking about the oceans. So there was a lot of pushback.
He also argued that iron is introduced to the oceans through
atmospheric dust. Those people did believe.
And that if you looked at the atmospheric dust flux,
which is proportional to the iron flux, you'd see that in the Atlantic
it is relatively high because you have wind patterns coming off these
deserts in Africa. And also over here in the Western
Pacific it's relatively high. It's low down here around the
Antarctic because there's no land source there. So these patterns of
dust delivery map on pretty well to this discrepancy to what we see and
what we model if nitrogen was the limiting nutrient.
So what John Martin argued was that there was lots of nitrogen and
phosphorus in these regions but there's not enough iron for the
phytoplanktons to actually utilize that.
Remember the Redfield ratio we talked about, how it's the
availability of nutrients relative to what's required by the plant that
determines what's limiting? So he did some experiments where he
went out in the boat and took samples. In the control sample he
would add nothing and another sample he would phosphorus and nitrogen and
another sample would add iron. And he was able to show that the
addition of iron caused phytoplankton to bloom.
He said iron is limiting in these regions of the ocean,
but everybody said bah, bah, bah, no it's not, we don't
believe you. They made up reasons why these experiments couldn't be
true. There are not zooplankton in the bottle so this and that and the
other thing. And so he persevered. And he said OK.
If you don't believe my bottle experiment, I'm going to go out and
I'm going to add iron to the ocean, then you'll believe me. So he said
we're going to go out with a boat. And what they did was, and my lab
was involved in these experiments. We had a small role, that's the
boat, in measuring a certain component of the phytoplankton.
But they pumped iron into the propeller wash of the boat and made
a zigzag path in the ocean where there is about ten kilometers by ten
kilometers. And the natural mixing in the surface ocean in about a day
would mix that iron through that patch. And, of course,
meanwhile the patch is moving. The oceans are moving, the patch is
moving, they've got these location buoys, the captain of the ship is
going crazy trying to navigate relative to these buoys rather than
relative to the solid earth. But we were able to actually follow
the patch. And, oh, here's John Martin who was also
a friend of mine. And sadly enough he died of cancer
before the first experiment showed unequivocally that iron is limiting.
But he knew it was so that was good. Anyway, he threw out this line.
ìGive me a half a tanker of iron and I'll give you the next Ice Age.
This was before the experiment because he was trying to drum up
enthusiasm for the experiment because he wanted to do the science.
But you see the connection here. So what's the connection between a
tanker of iron and an Ice Age?
Exactly. If you fertilize with iron, the phytoplankton photosynthesized
more. It could be argued that they draw
more CO2 out of the air and will cool the planet.
OK, so he got a lot of attention because of that,
even though this was a scientific experiment. So now I'm going to,
and we'll come back to that, of course, later.
I'm going to take you on an oceanographic cruise so you
know what it's like. And this is one that my post-doc
went on. This was not the first iron fertilization experiment.
There have been about five of them now, but this was one of the
actually one of the more recent ones that was done in the Southern Ocean.
They've been done in the subArctic Pacific, in the Equatorial Pacific.
I went on the one in the Equatorial Pacific because I'm a cruising
light-weight, but my post-doc went on the one in the Southern Ocean and
that's where these slides come from. But just to show you what goes into
doing this. These are the vats where they mixed
the iron which they mixed with an acid solution.
And they also put in sulfur hexafluoride which is an inert
tracer so they can use that to trace the patch. Here's the oceanographic
ship. What you do when you launch a cruise is you patch things in these
vans. And sometimes you have your whole lab in your van.
And, in fact, for this trace metal clean work they have special trace
metal clean vans where they're all Teflon lined and positive air
pressure and all of that. So you ship this out to the
Antarctic, and it gets loaded onto the ship, the van,
and then gets tied down. This is what the lab looks like
before the scientists arrive. It's just a bunch of tables that
are tied. And these labs get broken down and rebuilt for each cruise
because different types of scientists have different needs.
And this is what it looks like when everybody is settled in.
It's a very crude makeshift thing very crowded with equipment and
wires and is all set up temporarily for a month's worth of work.
So here's the shift leaving port. They're going out of New Zealand
which is where most of these cruises leave from for the Antarctic.
Here it is in the rough seas of the Southern Ocean. You cannot
see this very well. But that's an iceberg which is a big
problem down there, because that's just the tip of the
iceberg. So navigation is very tricky. So here's a radar showing
these icebergs scattered around that they have to look out for.
Here's another one. Here's how the samples are taken.
These little plastic PVC pipes are all electronically wired.
And this ball, when they're open,
is drawn into it. So when these are lowered in the water they fill up
with water, and then you trigger it and the ball shuts it and then you
bring it up. So you can set it, say this one goes off at 5 meters,
that one 20, that one 50, that one 100, whatever.
Wherever you want them you set them, and then it comes up and you have
your water sample. Working in the Antarctic is
particularly difficult. In this case this person is out
there taking the snow off of these incubators that have sample water in
bottles trying to make the phytoplankton think that they are
still in the ocean, but they are in controlled
experiments here. And they're taking the ice off so
that the light intensity stays the same. And this is to summarize the
results of the iron fertilization experiment just in a picture.
This is the water without iron added and this is the water with iron
added. The addition of iron to these waters causes major algal
blooms. And here is just some of the data. We can just look at
chlorophyll ìaî, which you know is a measure of
phytoplankton biomass in the patch versus outside of the patch.
And this is actually a satellite image taken off of the NASA
satellite of this iron-enriched patch.
So there is no question now that the availability of iron limits primary
productivity over vast regions of the ocean. I didn't think I was
going to use the board but I will use the board.
And because the Redfield ratio, which you guys now know, of carbon,
some nitrogen, some phosphorus. Remember? We talked about this,
106:16:1. If we add iron to this, iron is about 0.005. Anyway, tiny
amounts of iron are required relative to nitrogen and phosphorus
in order for a phytoplankton cell to grow.
So you can leverage, if there's abundance of nitrogen and
phosphorus, it just takes a little bit of iron to get this big bloom.
And that was very appealing to people. Any time it takes a little
bit of something to get a lot of something, I think people get
interested. And I think what motivated this whole interest in
ocean fertilization, I think, is motivated subconsciously
a lot by man's ability to manipulate a system so large with
so little effort. But that's sort of a [subset?
. So the success of these scientific experiments,
were really just to go out there and understand what regulated
productivity in the oceans, were picked up very rapidly by
entrepreneurs. And the proposal that was put
forward was to develop a commercial ocean fertilization industry where
you'd fertilize the surface oceans with iron.
And I'm kind of joking here that money comes out the bottom,
but I'll show you how this works in a minute. And turn this into a
business. And there are a lot of unknown questions here.
First the experiment showed that you could increase the phytoplankton
growth here, but they didn't show that you could increase this export
because the timescale of this is much longer than you can stay out on
a ship to follow it. So it could be that this is
increased and then this arrow is increased and you have no net flux.
There is a little data on this flux now, but it's not compelling yet.
Then the next question is if this was an industry,
could you actually verify how much carbon was exported, if
it could be exported? And then the collateral effects,
which we're going to talk about in a minute, could it be made profitable?
And the biggest question is what would the unintended consequences be
of such an intentional fertilization? And this is where you guys come in
because you have learned in this class a lot of things that could
help you assess what the unintended consequences are,
and we're going to talk about that. But how could you make money doing
this? And it depends on a lot of things.
Right now you couldn't, but there are people depending on a future in
which you could, and this is the way it works.
There is an emerging market in carbon trading credits,
especially for countries that did sign the Kyoto Accord where there's
a commitment to reducing CO2 emissions.
And so these carbon offset credits are worth money.
So the way this would work is, if it works, was you'd have this
industry, you'd fertilize with iron, you'd be able to claim that you
buried X amount of carbon in the deep ocean. And with that claim
that would give you these carbon offset credits that are worth money.
Utilities companies could then buy those, and if there was a cap on how
much carbon emissions they could have this would increase their cap.
So it's just like, you've probably heard about tree
plantations generating carbon offset credits. And that's a going
industry now. So that's how it would work. And there are companies,
these are some websites. Planktos.com, they have patents
filed on this process. How they're able to do that is
beyond me since it's published in the open literature,
in the scientific literature, but they do.
Their mission is to develop formulations to [manage?
phytoplankton productivity in carbon export.
There's another one that you don't have in your slides.
I just slipped this in this morning. But here's the website,
Green Sea Venture, if you're interested. But it's another
company that is marketing this idea.
And here's another. I just saw this ad last month in
[EOS?] which is a publication of the American Geophysical Union.
And it seeks professionals to work on an ocean nourishment
demonstration. This is a new word.
The oceans need to be ìnourishedî. So there's a psychology here.
They'll talk about ocean deserts that are nutrient poor,
need to be nourished. And this is not only for
sequestering CO2, but the claim is to increase wild
fish stocks by fertilization. And so some of these outfits are
really on the edge of credibility, and I will let you figure that out
yourselves. If you did enough research you could find out.
That's not part of your assignment for the class.
But some of them are actually really rational-thinking scientists and
engineers behind them. So there's a whole spectrum of
people interested in this. So why am I concerned about it?
In fact, one of my good friends, who is a very good scientist, really
thinks we should explore the idea of fertilizing the Southern Oceans to
bring the whales back. Because he thinks that the whales
are gone because the krill are gone, the krill are gone because the
phytoplankton are gone and the phytoplankton are gone because the
whales aren't there to recycle the iron. And we don't know any of that,
but that's the hypothesis. He thinks the ecosystem needs to be
ìjumpstartedî by an iron fertilization.
So just to give you an idea the way people are starting to think about
ecosystems and our ability to manipulate them.
So why am I worried about this? And why should you be worried?
Because you know now from taking this class that it's not that simple,
that ecosystems are complex. And you know that if you fertilize
with iron and you create a lot of organic carbon,
phytoplankton, and some of that settles, a lot of that settles down
to the deep ocean where there is no productivity, if it's consumed and
digested by bacteria oxygen is going to be consumed, right?
And respiration, heterotrophic bacteria,
that's what you learned in the first set of lectures,
oxygen will be consumed and CO2 will be regenerated.
But if you have enough of this it will actually,
the oxygen in the deep ocean waters will decrease and can even go anoxic
if you do it long enough. And when you change --
That's the function of the system, the oxygen concentration. You
change the community structure of the system and you'll have a
different assemblage of microbes there than you had before.
And one of the things that could happen, for example,
is that you would increase the ammonia concentration by this
reminerialization, you could stimulate nitrification
and denitrification, which you learned about in my second
lecture, I think. And you remember that a byproduct of
that is nitrous oxide. And nitrous oxide is also a
greenhouse gas that is 300 times more effective molecule per molecule
than CO2. In terms of its greenhouse capability,
in terms of its absorption of heat. So you're doing this whole thing to
suck CO2 out of the atmosphere, but if a side effect is creating
nitrous oxide, the amounts of which are impossible
to predict at this point, you could be worse off than you
started. And none of these proposals takes
this downstream effect into account. The other thing that can happen in
low oxygen waters is the stimulation of methanogenic bacteria which
produce methane that is 22 times more effective molecule per molecule
CO2 as a greenhouse gas. So there are ecosystem consequences
to this. You cannot just say I'm going to add
this and make carbon and that's the end of it, because you make carbon
and things happen to that carbon. The other thing that is overlooked
that you guys know about, remember this diagram of global
ocean circulation? If you fertilize the Southern Ocean
with iron and utilize the nitrogen and phosphorus here,
when those waters upwell over here along the equation that nitrogen and
phosphorus isn't in them. Now, that nitrogen and phosphorus is
fueling the productivity of these ecosystems upon which fisheries are
based. People are fishing the fish from those systems.
So those people should be able to say to these people,
hey, you took my nitrogen and phosphorus. That has to be factored
into your balance sheet. My loss of fish, my loss of income
from the fish needs to be factored into your balance sheet for
your carbon credit. And if you do that the profitability
is really marginal. Finally, there are models from a
group at Princeton that show if you do this in a sustained way that
after many, many years, this is 1500 which is the extreme,
but even after 100 years you create, this is latitude. Here's the
equator 40 degrees, 40 degrees south.
So this is a broad swath of the ocean and this is depth,
OK? So this shows a huge, huge anoxic zone in the oceans that
would be causes by sustained fertilization in this way.
Not surprising, you're making a lot of organic carbon.
It's going to be consumed by bacteria. So that is all a story,
a scenario to get you thinking about your future and your relationship
with the earth's ecosystems in the future.
Because our relationship with these systems is changing dramatically.
We are now in charge. We've been in charge for a while,
but we haven't taken the responsibility of being in charge
for a while of these systems. And your generation is going to be
making these kinds of decisions. As we move forward and we experience
the aftermath of some of the manipulations we've done in the past
like burning fossil fuels and increasing CO2 in the atmosphere
there will be choices to make. Do we just adapt to this global
warming or do we know enough about how the earth works to try to
counteract it in ways like fertilizing the oceans.
And then you'll have to decide are the risks of fertilizing the oceans
much greater than the risks of adapting to climate change?
And a new trend in thinking about the earth is thinking about nature
and ecosystems as not simply as something that we value because
they're part of our world and we should set up reserves so that we
can enjoy them and see nature and so generations in the future will know
what natural ecosystems look like, but starting to think of ecosystems
as things that provide services for humans and actually have a monetary
value that is not part of our economy, it's not part of our
economic system but they provide functions to our world for free.
And so as we destroy them we're losing those functions.
And this is a very well known paper. There's a journal called Ecological
Economics that tries to talk about factoring in ecosystems
into our economy. And this is a very well known paper
on the value of the world's ecosystem services and natural
capital. And course this is impossible to do but you've got to
try. So they evaluated the ecosystem services as worth $33
trillion. And this is just a brief list of some of the services that
they analyze in this. One that's pretty easy to wrap your
brain around is the pollination of crops by insects.
We rely on insects to pollinate crops. They do it for free and we
rely on that. And just this is estimated to be worth $6 billion.
That if you had to hire somebody to manually pollinate your crops if
there were no bees and all of the things that are doing it,
it would cost $6 billion globally. There is decomposition of waste,
recycling nutrients, dispersion of seeds, control of pests,
purification of the air and water, ecosystems to do this. And this is
compared to the GNP of $18 trillion per year, the global gross national
product. So this is sort of a shift in our thinking about how we think
about ecosystems. And just in the last --
This slide was in one of your handouts about,
I don't know, five lectures ago, but I didn't get to it so I thought
I would bring it in now. Just in the last, well, April 14th
was announced this Millennium Ecosystem Assessment Report,
which was over a thousand scientists worldwide assessing the state of the
earth's global ecosystems and from the point of view of strengthening
capacity to manage ecosystem's sustainability for
human well-being. So the focus is on how do we manage
these things for ourselves and the future generation?
And you can go to the website if you want to get depressed.
Well, you can get depressed about what we've done.
But you can be optimistic that we're really facing up to this
challenge in a very systematic way. But the bottom line is that
two-thirds of the natural machinery of the earth has already been
degraded by humans. And water use is dramatic.
Major rivers are dry before they reach the oceans.
We are mining groundwater basically. We're taking water out of the
ground much faster than it's being recharged. One-quarter of all fish
stocks are already over-harvested. I mean we're in a non-sustainable
mode. I don't need to tell you. You read the newspaper and you know
this, and so I'll skip over this. Oh, just this last part I think is
the most important. The argument is that more and more
people are going to be living in the cities in the future,
so less and less in touch with nature. So nature is going to be
more and more of an abstraction to us. And people are really worried
about this because conservation of natural spaces is not just a luxury.
This is a dangerous illusion that ignores our dependency
on these systems. And we have to really strengthen
that understanding. OK, so now I want to lead you,
this slide several students have told me is the only thing they
remember from this class and my other ecology class.
And that makes me very happy. If this is the only thing you
remember that's great because this is really the take-home message for
you and your generation. And this is how we have changed our
relationship to the earth and this is where we are right now.
So you learned in the first lecture about the biosphere,
autotrophs producing organic carbon, heterotrophs consuming organic
carbon and with a little bit of input from the earth's crust,
nitrogen and phosphorus, and this system running pretty well
before humans. And before the Industrial Revolution
societies fit into this system of tight recycling taking a little bit
off of the autotrophic productivity and putting a little bit of waste
into the system. But then we had the Industrial
Revolution. We've cut down massive amounts of trees.
we've changed the very landscape of the autotrophic system,
and we've dramatically increased the waste stream.
And we're mining the lithosphere in a huge way, elements,
mining for metals and things used in manufacturing,
etc., which is, of course, increasing this waste
stream. So this is where we are now. And we know that this is not
sustainable the way we're operating. So this is your generation's
decision. Are you going to go this way or are you going to go that way?
Very simple. You've got to point your compass in the
right direction. So this way just increases these
streams, the waste stream and the erosion of the natural ecosystems
and the mining from the lithosphere. This stream works toward recycling
within the societies that we've already built,
restoring natural ecosystems so they can do their functions properly for
cleaning air and water, and leaving enough productivity for
the rest of the heterotrophs on land.
You know we're not the only heterotrophs. There are all these
other species that rely on this primary productivity,
the birds and, well, all the species. So we need to leave some of that
for them so the ecosystems can sustain themselves.
And so this is where we should be. And we just need to find the will
to get there. So easily said, not easily done.
And there's an organization called The Natural Step.
I put this website, which you might want to write down
because I don't think this was on your slide, if you're interested you
can write it down, that I think has a very,
very creative approach to working with industry to try to direct
things in the right direction and where they talk about the compass.
And they say there are basic system conditions for sustainability that
if we don't maintain we will be going in the wrong direction.
And it's just a total no-brainer. It's very simple. Substances from
the earth's crust must not systematically increase in nature.
Obviously, that's not sustainable if you do that and substances
produced by society must not systematically increase in nature.
We cannot keep pouring waste into nature. The physical basis for the
productivity and diversity of nature, i.e., the green part,
the autotrophic cycle cannot be systematically deteriorated.
And then they add to this we must be efficient enough to meet basic human
needs. We have to work toward efficiency which is working toward
tightening this recycling here. And they've been very effective in
many countries in pointing industries in the right direction.
Every time that they make a decision about what metal to use in
a particular manufacturing process, they look at how much of that metal
has already been mined. Is there an alternative metal that
they could, etc. They're constantly using at this
compass. OK. Obviously, the compass is not pointed in the
right direction. A no-brainer. Building cars that
use more fuel and get less miles per gallon is not the right direction.
So some of these are very easy to answer. And I don't want to cast
dispersion on SUVs, but in case you didn't recognize it
that's what that is. I mean fuel efficiency is here,
we can have it if we want to, and we need to work on that.
And finally, well, this isn't finally. This is second to finally.
I love this cartoon. This is the [doctor Saturn?
or whatever looking at the earth and diagnosing our planet at this
stage in its evolution. And finally I'll leave you with
this image which is my favorite image of the earth because it has no
national boundaries and it really does remind us that it's a living
planet and that time is now. I mean, I know this sounds
overdramatic but it's not. I mean we've changed this planet so
much in the last 200 years relative to all the years before.
And the next 50 years, your time to make a difference is absolutely
critical, so I hope you guys will go off and save the planet for us.
Have fun and have a great summer.