Hello. I’m Reagan Waskom, chair of the Water
Center at Colorado State University. Welcome again to our online course on water, civilization,
and nature, addressing 21st century water challenges. Before we get started, a few pieces
of course business. Naturally, you’re free to select from the offerings in this course,
the lectures, and the online features that are of particular interest to you. We do however
have a suggested sequence for the topics and lectures which presents the topics in a logical
order building somewhat on each other. The sequence is reflected in the transitional
comments that you’ll hear me making as we go through the course.
Water is frequently thought of in terms of its cycle, from evaporation to clouds to rain
and back to earth where precipitation may evaporate again, linger in the snowpack, runoff
into rivers, get stored in lakes, or infiltrate into aquifers. If you’re already familiar
with the various parts of the hydrologic cycle, you may want to stay with me for this introductory
lecture. If you’d like a brief introductory refresher on the various pathways and storage
compartments represented in the hydrologic cycle, you might enjoy visiting the pages
in the introductory model on the water cycle. From the distance of outer space the planet
we live on appears as a beautiful blue circle. We call it planet earth but it could easily
be called planet water. 71% of the earth’s surface is covered in water. From space it
would be hard to imagine that this planet has water scarcity problems.
On our planet, water exists in liquid, vapor, and solid forms, moderating the climate and
creating the medium for life. Indeed, life teems and evolves in fresh and salt water
on planet earth. Water effectively mediates all biological processes. Without water, proteins
don’t work and life as we know it would not exist.
As humans, we’re defined by water. 65% of the human body is water. The relationship
between humans and water determines where we live, how we live, and what we do. Society
has always positioned itself in proximity to water to meet our basic needs for transportation,
protection, commerce, and food. It’s interesting to contemplate how central
a role water has played in belief systems throughout human history. The human spirit
somehow understands water as the great beginning. Kate Johnson notes in her book “Earth, Water,
Fire, and Air” that the Hopi Creation Myth starts with, “In the beginning the earth was
nothing but water.” Water is not only an aspect of indigenous spirituality, but a major component
of that spirit world. Water, whether as a substance or in the form of lakes, rivers,
or meteorological phenomena such as rain, snow, fog, and clouds, are seen through a
spiritual, not an economic lens. Contrast that view to the western view of water as
an economic good that can be owned or used as a vehicle to transport waste away from
our settlements. The Maori tribes from New Zealand were confounded by the European view
of water as something that could be owned or used to transport sewage effluence. Yet,
our modern society does this every day without question.
The ancient works of previous civilizations reflect that reverence for water. The sound
of water, the feel of water, the look of water. It sustains, it cleanses, it’s the essential
element for growth and renewal. Water has inspired us to poetry, music, and
art as well. While D.H. Lawrence pondered the miracle of
water, as scientists we know that the molecular properties of the hydrogen bond of water is
the key to understanding water. The water molecule is polar, it’s sticky. Water molecules
cling together. Water stays liquid through a very wide temperature range, allowing life
on earth as we know it. It absorbs heat, allowing living things to regulate their temperatures.
The solid phase is less dense than the liquid phase. Water is a great solvent. It facilitates
the biochemical reactions of life. Water molecules are tiny. One human red blood cell can hold
three trillion water molecules. Although we live on this watery planet, the
irony is that most of the water on the planet is not easily available for our use. Still,
the amount of available freshwater is a tremendous resource. You notice the small dot reflecting
the relative volume of freshwater on planet earth.
Water is not static like other natural resources such as coal or other fossil fuels. Water
is in motion, driven around the globe by solar energy, it captures and moves solar energy.
The result is purification, renewal, variability, and the extremes that we see in water.
The world pattern of precipitation shows large disparities between large annual rainfall
in the tropics where some areas get in excess of 10 meters of precipitation annually and
the semiarid and arid regions such as the Saharan Desert that receive almost nothing
at all. It’s hard to live in either extreme but humans manage to do so.
Globally three are a number of serious challenges facing us in the 21st century regarding water
that will define how we live. These challenges include sanitation and access to clean water,
water for development, food security, weather extremes, ecosystem services, water for energy,
water quality. We’ll dig deeper into each of these during the course.
One major change factor is that since 1947, since World War II, consumptive water use
worldwide has increased more than 400%. You can see this in this chart that show both
population and water withdrawals over time, over the last century. There’s a direct correlation
between global population grown and the increase in freshwater consumption.
Now, we’re talking about these challenges as global problems. That is because the problems
span the globe. But in reality, all water problems are local. There’s really no global
water crisis. There’s thousands of local water problems around the globe.
The Falkenmark Water Scarcity Index assumes that the absolute minimum of 100 liters per
person per day is needed each day for hygiene and cooking. A minimum of 1,000 cubic meters
per capita per year is the level for water to the economy and human wellbeing. You can
see on the chart, the red areas where the Falkenmark Water Scarcity Index assumes that
there’s a problem. Humans are also heavily dependent on rivers,
oceans, and estuaries for a great deal of our total protein intake as well.
This slide shows water stressed regions. Please note that the majority of the 24 megacities,
that is those cities with greater than 10 million people, are found along the coast
within regions experiencing mild to severe water stress. This is particularly true for
the cities located on the Asian continent. Water stress is the measure of the amount
of pressure put on water resources and aquatic ecosystems by the users of these resources
including the municipalities, industries, power plants, and ag users that line the world’s
rivers. Also please note that there are 263 international shared river basins worldwide.
The global overview of water availability versus population stresses the continental
disparities, in particular the pressure put on the Asian continent which supports more
than half the world’s population but only has about a third of the world’s water resources.
Compare that to North America, South America, and Europe if you will.
In the US and other industrialized nations, most of water withdrawals are for energy,
agriculture, and public water supply. Clean water is fundamental to human health.
According to the United Nations, the human right to water is a prerequisite to the realization
of all other human rights. This brings up the question of whether water is a property
right or a human right. In the US, I think you’d have to argue that it’s both.
It’s been estimated that women in developing countries spend up to six hours per day collecting
and purifying water. This situation increases the income and economic disparities as well
as educational disparities experienced by women and girls. Most of these live in Asia
and Africa. There’s also the issue of what qualifies as
adequate sanitation and safe water. Safe clean water costs money. The poor may
pay a disproportionate fraction of their incomes for this service. It’s interesting that the
same people who lack water also lack adequate food, sanitation, healthcare, and are most
likely to be affected by natural disasters. This is the so-called multiple burdens of
water poverty. Nearly two million children die each year from water born disease. Sixty
million children are stunted due to water-borne diarrheal diseases, over two billion humans
lack access to sanitation facilities, exacerbating the problems of water-borne disease. We talk
about how to engineer fixes to these problems; getting it accomplished in a manner that’s
self-sustaining is the challenge. Switching to agriculture, irrigated ag consumes
huge amounts of the water used by humans—about 70% of the total used. Global food production
doubled in the second half of the 20th century and currently 18% of the world’s 1.5 billion
hectares of crop land are irrigated, but food comes from this irrigated land.
Irrigation tends to be concentrated in the arid and semiarid regions where it represents
a significant share of cropland, as well as in the humid tropics of Southeast Asia, where
irrigation is made possible to move from one or two to two or even three harvests of rice
per year. Much of that irrigation occurs on small farms
in India and China, which are the #1 and #2 irrigated nations in the world, followed by
the United States with about 56 million irrigated acres.
Water for food is a global challenge. We’re expecting a 40% increase in population by
2050, doubling the demand for food. As societies develop, the demand more animal protein which
requires more grain and hence more water. The bottom line is we much grow more food
with less water in the 21st century. US Farmers today use less water than they
did just 30 years ago, yet produce 70% more food. We’re on our way, but we still have
a long way to go. Another major topic that we’ll cover in this
course is climate and extreme hydrologic events. Drought is the biggest of these, but clearly
typhoons and hurricanes and flooding causes much human misery. This figure shows the increase
in major natural catastrophes since the 1950s. What you see with that increase, it reflects
the increase in human population. The earth has always used extreme events in water often
in the form of tsunamis, floods, droughts, to do its business of moving mountains, rivers,
and species about. Extreme events become catastrophes when human civilization gets in the way.
The results are often disastrous. Hurricane Sandy on the US East Coast and Hurricane Katrina
in New Orleans showed the vulnerability of our coastal cities to extreme events.
How has the western world adapted to hydrologic uncertainty, floods, and drought? Through
harnessing the power of water. Mankind has been using water as a source of
power for centuries if not millennia. In Imperial Rome, water-powered mules produced flour for
grain and were used to saw timber and stones over a thousand years ago.
More people, more development, means more water engineering on the planet, and altering
rivers for irrigation and energy and the like, has both benefits and concerns that we need
to think about. This chart shows the history of global dam
development going back to the 1700s. What you see is how quickly in the 20th century
dams propagated across the planet. In the US, the era of large dam building is
nearly over, but globally dams are being built to control floods, to store and distribute
water, as well as to generate much needed electricity to power growth.
Unfortunately, one of the outcomes of these massive projects is the displacement of human
settlements, but there are environmental considerations as well.
When water systems were designed in the 20th century, the question was how much water can
we reliably withdraw from the river? Today’s question is, how much water do we need to
leave in the river for those living things? Clearly species that rely on aquatic ecosystems
to sustain them evolve to require certain hydrologic conditions, both in terms of high
flow, low flows, temperature, and others. The final topic we’ll cover in the course
is that of water quality. Water must be of suitable quality to meet its intended use.
Water quality constrains use just as surely as having adequate flows does.
Globally, the #1 challenge is insufficient access to potable water for drinking as well
as civilization. In the industrialized world, municipal and
industrial wastewater, urban and ag runoff of poor quality are the number one issue.
Much of the problem that results is due to sedimentation, also to the movement of nutrients.
This issue of global nitrogen pollution and the changes that that causes to the environment
is a significant problem of the 21st century that we’ll have to deal with.
Not only does it cause problems in freshwater ecosystems, but clearly our oceans and estuaries,
our bays, suffer from hypoxia, these oxygen depleted zones where nutrients are too high.
If you note where those zones are, especially where they happen persistently, they tend
to be around major cities and industrial areas. Why the sense of urgency to address these
water challenges? Clearly the world population is growing most rapidly in water-short regions.
Water demand is increasing. The potential for conflict between water users is increasing.
Climate and multiple severe droughts since the 1990s have had significant impacts and
raised concerns about our increasing vulnerability as a society. Water supplies are fully or
over-appropriated in many river basins around the world as well as many of the major aquifers.
Most levels of government are poorly prepared for water disasters, for drought, for the
increasing water needs due to population growth, and climate variability. Finally, existing
water laws and institutions are not able to accommodate all of the needs.
Then, there’s issue of climate change and its impact on water resources.
How can you make a difference? Education and awareness is important. Personal action and
support for better governance at all scales. Additionally, you can certainly investigate
you and your family’s water footprint. Find out how your use of energy, the way you eat,
and the things you consume, impacts water resources.
There’s big challenges ahead in water resources management. Education, local action, innovation,
technology, better governance and management at all levels, will be required to meet these
challenges. We’re glad you’re taking time to learn more about water resources through
this open online course. Now, regarding the course from here. Naturally, you’re free to
select from the offerings of the course, the features that are of interest to you in the
sequence that is of interest to you. We do however have a suggested sequence for the
topics and lectures which presents them in a logical order, building somewhat on each
other. When you finish watching the lecture for each module, there are additional activities
and reading for each area. If you’re interested in earning a Statement of Accomplishment for
the course, you should visit the discussion forum for each module, post your comments,
and respond to at least one other student’s comments. You should also take the quiz for
each module. There’s 8 questions per quiz and you will need to answer 6 correctly to
pass the quiz. In addition, there’s a number of optional links for interactive exercises,
readings, and CSU resources. Thanks for joining us on this exploration