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).
Coal & Gas
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來自 University of Illinois at Urbana-Champaign 的課程
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Energy
In this module, we will look at energy use. We will also consider what the trend of energy use means for the planet, and how we might transition to a more sustainable pattern of use.
與講師見面
Dr. Jonathan TomkinAssociate Director
School of Earth, Society and Environment
I'm Jonathan Tomkin from the University of Illinois.
Fossil fuels dominate the energy portfolio of the United States.
Note that oil and coal are down from their peaks, while natural gas continues to
increase. Natural gas and coal are very important in
the US electricity supply, and one of the reasons for this is they have a very high
energy return on energy invested. Coal is about 100.
They also have many of the other advantages of oil.
They're energy dense, they're cheap ways to produce electricity, and, in fact, in
some places, getting cheaper, and also, they're sources of, of supply that can be
stored. We can turn on a natural gas turbine when
we need the energy. We don't have to wait for the wind to blow
or for the, or the sun to shine. So, because they sort, supplies of energy
have not been running out in the United States.
Prices of electricity have been broadly flat, over the last 50 years.
Coal is still the cheapest technology for delivering electricity in the United
States. Coal has another advantage all around the
world. It's available in places where oil isn't,
so there aren't security concerns. Again, this is because coal is the product
of natural processes. And so there is a geologic reality of
where coal is located. Some of the biggest industrial countries
in the world, places like China and the United States.
Also have plentiful supplies of coal, so they can use that coal to supply their
industries. Of course coal has major issues.
Perhaps the most foremost for a course like this is the fact that it produces
more carbon dioxide per unit of energy than any other energy source that's used
widely. It also produces other environmental
affects, Acid rain, mercury, and heavy metal contamination, ash, and sludge.
It does appear that there is a lot of coal left.
Although some countries such as the United States are using less coal now than they
did in the past. Our point of peak coal use was in 1998.
Total reserves are thought to be very large and worldwide peak coal is not
expected to occur for decades yet. Most experts think that current rise of
use, is enough coal for the rest of the century and for some of the next.
So, as for the sustainability point of view, the danger of coal is not that we'll
run out of an energy source, danger is that we, the pollution of coal is not
something we can cope with. There's another fossil fuel which is not
quite as dirty. In particular, it produces less carbon
dioxide, significantly less, per unit of energy produced, and that is natural gas.
Natural gas also has less security concerns than oil, as it's found in many
more places. Especially the new unconventional
supplies, such as shale natural gas. New fracking technologies has meant that
we can extract natural gas from many places where it was previously thought not
possible to do so. And this has increased reserves
enormously. Ten years ago, when I first started
talking about our sustainable energy supplies, the global estimate was around
50 years of use left. Today because of advances in technology,
experts have said that there could be 200 years worth of use.
So natural gas like coal can see us well through the twenty-first century.
Again however it produces carbon dioxide. So the question is not will we run out of
natural gas. The question is, can we handle the
pollution produced? Furthermore, just as we saw for extracting
unconventional oil supplies, there are additional environmental concerns for
extracting unconventional shale natural gas supplies.
The fracking technique is not very well tested and could cause additional
environmental problems. For example, fracking requires the pumping
of high pressure fluids into the earth. And it's not clear what is exactly in
these fluids. They have chemicals in them to make them
slippery. Some people worry that if these chemicals
get into fresh water supplies, that we could contaminate aquifers.
Geologists think that as long as the aquifers are far enough away from the
natural gas shales, and often they're separated by hundreds or even thousands of
feet, then there shouldn't be very much contamination between the two.
And the general consensus at the moment is that although unsafe, events can occur,
it's not any more inherently unsafe than any other methods of extraction.
Nevertheless, it's a new technology, and it's possible that there will be
unforeseen, or even foreseen, problems that will outweigh some of the benefits.
But as a consequence of this new technology, supplies are going up,
extraction is going up and there is no peak.
There's easily enough natural gas to supply consumers in the United States and
Europe, two big industrial centers, throughout the century, and that's from
local supplies. So coal and natural gas can see us
throughout the century. But remember this coal and natural gas
took million of years, tens of million of years to create, so we are using them up
in an unsustainable fashion, and if we look at the scale of civilization which
lasts for centuries and even millennia, we can say that our current methods are not
things that we will be able to do in the long term.
And of course, there is a bigger environmental problem.
The trend in carbon dioxide emissions is not sustainable.
If we continue to use oil, natural gas, and coal at the rates we have been using
them, then we're going to make a much larger change to the climate than we would
be if we started to reduce the amount that we used.
In fact, it's possible that we might need to do things like geo-engineering, to try
to counter the effects of the predictive large increase in temperature that would
be caused if we used up all our fossil fuel supplies.
So, moving away from fossil fuels is a big challenge.
Remember, that these three types of fossil fuels are around 80 percent of the world
energy portfolio. So, this is one of the hardest challenges
the world faces in becoming more sustainable.
What are our options? We'll start looking at those options in
the next lecture. >> Produced by OCE Atlas Digital Media at
the University of Illinois, Urbana, Champagne.
