This course introduces the academic approach of Sustainability and explores how today’s human societies can endure in the face of global change, ecosystem degradation and resource limitations. The course focuses on key knowledge areas of sustainability theory and practice, including population, ecosystems, global change, energy, agriculture, water, environmental economics and policy, ethics, and cultural history. This subject is of vital importance, seeking as it does to uncover the principles of the long-term welfare of all the peoples of the planet. As sustainability is a cross-disciplinary field of study, this foundation requires intellectual breadth: as I describe it in the class text, understanding our motivations requires the humanities, measuring the challenges of sustainability requires knowledge of the sciences (both natural and social), and building solutions requires technical insight into systems (such as provided by engineering, planning, and management).
Sustainability Metrics, Part 1
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从本节课中
Measuring Sustainability
In this module, we will examine what tools are available to measure sustainability. Finally, I will make some predictions on global sustainability for the 21st century, based on the models we have spoken about in this course and the trends that have been observed in the early part of this century.
与讲师见面
Dr. Jonathan TomkinAssociate Director
School of Earth, Society and Environment
I'm Jonathan Tomkin from University of Illinois.
Environmentalism has actually been around for a long time, even Western countries.
Medieval cities like fourteen Century Paris and London had rules against dumping
animal carcasses within the city limit. And, of course, as we saw from the Tragedy
of, Tragedy of the Commons solutions, local groups have been caring for local
pastures and range lands for centuries. In industrialized countries,
We've began to think a lot more about the global problems to do with the
environment. And, not just the global problems,
We actually have also began, begun to think about the environment as having it's
own worth, in other words an intrinsic value.
This is actually quite recent in industrial countries.
It probably came about in the 1970's. There were movements all around the world
including in non-Western countries like India, but we often associate this sort of
movement as beginning in the West in places like San Francisco which held the
first Earth Day in 1970. And, since then in the ensuing decades,
environmentalism has become a very mainstream political way of thinking.
Many organizations do a lot of green things that they didn't used to do in the
50s' and 60s'. And so there are green parties now and
they often share power in parliaments and governments around the world.
And, This agenda of environmentalism isn't just
about those local issues which people cared about primarily in those earlier
centuries. These issues are now about things like
global warming, or about saving the rain forest,
Or species that are not within the national borders.
So, for example, whales, or polar bears, or pandas.
What's interesting about this diversity of environmental thought is that it spread
beyond political movements and social movements and even to the corporate world.
Now, in some cases, this might be an example of what's known as green washing
and that is sort of using environmental concerns as a PR.
But, even there, you can see that's the impact of the green movement that has made
caring about the environment a very mainstream thing to do.
But, it looks like corporations are even going beyond that, right?
They're not just doing it for the image, they really do want to streamline their
services and create less waste, for example.
So, given this background, we could hardly say environmental groups are triumphant.
So, why aren't they celebrating? Why isn't there a big success?
And I think the reason for that is environmental groups and individuals
concerned about the environment actually don't see as much progress as they think
as necessary for saving the planet and making it sustainable.
So, why might environmental groups not feel that we've reached this sustainable
state? How do we know?
Well, in this lecture, I'm going to talk about sustainability metrics.
And these are ways that we measure the environment to try and determine how
sustainable a process is, or how much damage is being done.
Now, we talked about this a little bit earlier when we described ecosystem
services and the attempts to value that. And it turns out that, that becomes an
important component in a lot of the ways the sustainability metrics try to estimate
our progress towards sustainability. A lot of these metrics come out of this
set of rules sometimes known as the Daly Rules, maybe not explicitly, but it's
often the same set of thinking. And there's three sets of rules.
The first rule talks about renewable resources must be harvested basically at a
sustainable rate. And so, an example of that is that might
be that fish or timber should be harvested at the rate that fish reproduce or that
trees grow. Secondly,
It's natural that we do use some non-renewable resources.
So, right now we're using fossil fuels, And you might argue that some other
resources, for example metals, or other mined things are in some sense limited as
well. So, as we use those, the Daly Rule
suggests that we must develop alternatives to replace them at the rate that they're
being lost. So an example for that might be, is as we
use up fossil fuels, we should be developing renewable energy sources.
And finally, there's this idea that the amount pollution that we create should be
matched by the environment's ability to assimilate it, that is absorb it.
And a good example of that would might be carbon dioxide.
Since industrialization, about half of the carbon dioxide emitted by human activities
have actually been absorbed into the oceans and to the land. and in this way,
the natural systems actually being overused, right?
We can see that we're not matching the carbon, the ability of the natural
environment to absorb the carbon dioxide that we are producing.
So, we can produce some pollutants like carbon dioxide, but under the Daly Rules
we can't produce more than the environment can absorb at once.
Proponents of this way of thinking see these rules as foundational because in
some ways they're physical limits, and they're sort of no way around them if you
like. If we want to be sustainable for any period of time, we have to obey these
rules. So, these rules are used generally
explicitly in sustainability metrics but they're used as the foundation for the
assumptions and the thinking that go into building these metrics.
One very popular idea, and I know I've used this word myself a lot in this
course, is the foot-printing idea. And so, we might think about an
environmental footprint that somebody has on nature and there's lots of versions of
this idea. There's the ecological footprint, a water
footprint, energy footprint, and a carbon footprint, might be some of the ones that
I've mentioned. Let's look at a couple of these in detail
in particular, the ecological footprint. In the last lecture, we spoke about
ecological services. Ecological footprint is a measure of our
consumption of those ecological services. Now, if we consume more of those services
than the land can support, then we could argue that we're in an unsustainable
state. An ecological footprint can be assessed
for an individual, a region, a country, or the whole planet.
How do we calculate this? Well, firstly,
We determine the consumption of particular ecosystem services by that individual, or
nation, or organization. This includes things like food, housing,
energy, transport, And things that require the use of the
land. By using the ecosystem services idea then,
we can see how much land is needed to provide each of those services.
And so, it really is a footprint, insomuch that the measurement then, is a land area.
How much land area does an individual, a country, or the whole nation need to
provide the services that it's consuming. Clearly, this varies from region to
region. Developed countries have ecological
footprints of between three and five hectares per person with the United States
ranking the highest. The world average is estimated to be
around 2.2 while the in, ecological footprint of a developing country, like
India, is thought to be about.4 hectares per person.
So, in principle then, we can figure out whether or not the Earth is on a
sustainable course by adding up all of these ecological footprints for every
person. So, if you do this, you can estimate the
total number of Earths we would need to provide the ecosystem services that we
rely on. If we have more that one Earth, then we're
in trouble because we're not using things sustainably.
Estimates vary but one recent value suggested that we're using about 40% more
land than is actually available on the Earth.
So, in other words, we would need about 1-1/2 Earths to match our consumption
patterns. This is clearly not sustainable.
And. of course. you often hear things that if the all the world lived like the United
States then we would need around seven Earths because the population of the
United States is relatively small relative to the population of the planet but it's
consumption rate is very high. There are some problems with this idea
though and I'd like to talk about those. And these illustrate the difficulties of
making a reliable sustainability metric. Firstly, it has a particular problem in
that it is often used to compare different countries.
This sort of inter country comparison is often unreliable and unfair.
Let's think about some of the places that are actually more sustainable than others.
In western countries, the most sustainable places are generally the cities.
City dwellers use less resources, they have smaller apartments, they take public
transport. So, in fact, the carbon emissions, for
example, for someone living in the city is usually significantly less than somebody
who lives in the suburb or a rural area. So, on that sense, we would say that the
city dweller is in some ways maybe more sustainable.
But, in an ecological footprinting analysis, they actually appear to be much
less sustainable. That's because there's hardly any land in
the city per person. And so, obviously comparing a city to the
country as a whole might be a little bit unfair.
Similarly, though, some countries are much urbanized and much denser.
A good example of this might be comparing the United Kingdom and Australia.
Australians are, in some measures, are as polluting as Americans.
But, according to the ecological footprint idea, they're in the black because the
country is so large relative to the small population.
Meanwhile, the denizens of the United Kingdom, we've much more efficiently in
terms of, say, energy use, they use about half as much energy per person. And yet,
because the land mass is less, it looks like, according to the ecological
footprint idea, that individuals there are behaving less sustainably.
So, this idea doesn't take into account things like trade between regions or
nations, Or the development of, for example, our
new technologies. One of the things that's Why cities are so
successful and thriving in the modern world is because of their fonts of
innovation and the provide new services, new ideas, and these new ideas could help
us live sustainably in the future. A second problem with ecological foot
printing is it doesn't really know the difference between sustainable use of land
and unsustainable use of land. It really just looks at the consumption of
that ecosystem servers. And actually, this becomes the very
important question is. it doesn't matter if we're using land as long as we're using
it sustainably. But, it turns out that it's very difficult
to measure. And, when you look at something at a
regional scale or indeed a global scale, clearly, you don't have very much
information about each piece of land, right?
You're making some kind of aggregate average.
So, so that makes it a very difficult measure to rely on in terms understanding
are we truly being sustainable. What's more is that the way that the land
is measured is very binary at time. It's being used for one thing, or, and
nothing else. Whereas, in reality, land is often used
for many different things at the same time. And if we do use land for many
different things at the same time, then it's actually providing multiple ecosystem
services. And so, perhaps the land is in a sense more productive than the ecological
footprint idea would have us believe. Finally, I would point out that
technological change is also missing from the ecological footprint. And if we refer
back to the original Daly Rules, We know that we can replace non-renewable
uses as we develop better technology. And, in an ecological footprint
measurement, we don't collect that information.
We don't know that solar cells are actually cheaper now and more efficient
than they were ten years ago or twenty years ago, for example.
So that there are some issues with the idea of using ecological footprint and
relying on that. Produced by OCE, Atlas Digital Media at
the University of Illinois Urbaba-Champaign.
