- A sunny July day is perfect
for a boat ride on Lake Mendota in Madison.
- Dave Harring: Okay, we might as well move the ladder back here more.
- But this boat is filled with researchers,
not sunbathers,
and their goal is to travel back in time.
- Stephen Carpenter: We know from historical accounts
that the lake was ringed with white beaches.
It was just a beautiful...
- Professor Steve Carpenter is the Director
of the Center for Limnology at the University of Wisconsin.
He says white settlers first came to Madison in the 1830s
and their written reports indicate
the lakes were not brown and filled with green algae,
as they are today.
- Stephen Carpenter: One of them is dated
early July and talks about
being able to see to the bottom
in very deep water
and at the bottom it's white.
- Harring: And we're going to add ice.
Ethanol, ice, ethanol.
- Carpenter and colleague, Dave Harring,
will use a freeze corer...
- Harring: If you look down here, you can see
where it's already starting to supercool.
- ...to bring some of that white bottom to the surface.
- Carpenter: What we're going to do
is freeze a layer of sediment
on the outside of that cylinder.
- Harring: Okay, you guys ready?
- Carpenter: The reason to core lakes
is to learn about the history of the lakes.
Each year,
about a millimeter of sediment
will be laid down in this lake.
Previous core samples have shown the lake bottom
changed from white to black
between 1850 and 1870,
a time when most of the land around the lakes
was plowed and farmed for the first time.
- Harring: See up here, though, the really soft stuff.
- Carpenter: Right here is the boundary
between the glop and the harder, lighter-colored sediment.
- Harring: The dark stuff here is algae
and pretty much from 'settlement-on' runoff.
- Today, the original white bottom of Lake Mendota
is covered in about a foot of black goop,
the product of 150 years of agricultural runoff.
Carpenter says it's important
for people to know the lakes weren't always green,
and that the whole region
continues to be in a state of transition.
- Carpenter: There's a tendency to extrapolate from the present,
both to the past and the future,
and the sediments show us
that this has been a place of dramatic change.
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- Funding for Yahara Watershed: A Place of Change
was provided by
the Water Sustainability and Climate program
of the National Science Foundation.
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- As if turning clear lakes green wasn't enough...
there may be even more dramatic changes to state watersheds
in the future.
Steve Carpenter is one of a handful
of UW Professors and students
working on a research project called Yahara 2070 .
- What we want to do is create a long-term perspective
on change in the Yahara Lakes.
- Yahara 2070 is funded by
a grant from the National Science Foundation
to look at the impact
of climate change and human decisions
on the Yahara watershed.
The watershed is the 536 square miles
that drain into the Yahara Chain of Lakes
and eventually flows into the Rock River,
which, in turn, eventually flows into the Mississippi.
2070 refers to the future.
- Chris Kucharik: The time frame of using
2070 I hope is helpful to people to think about
"Okay, that is my grandkid's or it is my children's future."
- Chris Kucharik is a Professor in the Department of Agronomy
at the University of Wisconsin.
He says most people consider long-term
to be five or ten years.
But environmental changes occur on a different scale.
- Kucharik: They're embedded in 5, 10, 15, 20, 50-year, 100-year
type of transitions that we make as a society.
- A trip to the bottom of the lake shows
what the last 150 years
of environmental changes looks like.
Yahara 2070 asks
what the watershed could look like in the future,
and it combines storytelling and science
to paint a vivid picture.
- Carpenter: Thanks to all of you for coming and joining us
in what's really an experiment.
- A group of clean water advocates and activists
are eager to learn about scenarios
created to depict four possible futures
in the year 2070.
The researchers interviewed dozens of people
to ask what they thought
the future might hold for the watershed.
- Carpenter: We gather
beliefs about the future.
So, what are people's hopes?
What are their fears?
- Professor Carpenter and his team
took those hopes and fears
and created four stories...
four different scenarios
that tell what it's like in the year 2070.
- Carpenter: Each of these stories is fiction
because nobody knows what's going to happen in 2070.
- In each scenario,
climate change in the 2030s and 40s
causes a major shift in how society survives.
Professor Carpenter says the ideas
may sound like science fiction,
but they're entirely plausible.
- Carpenter: So everything exists now,
it's just that we amplified certain elements in each story.
So in "Connected Communities," for example,
we amplify sustainable values.
- In a future with "Connected Communities,"
consumer choices and supportive policies
help farmers implement more conservation practices,
in order to reduce
agriculture's impact on the land and lakes.
- Carpenter: In "Abandonment and Renewal," we amplify
doing nothing and complacency about environmental problems.
- In this scenario,
a focus on increased farm production leads to more runoff,
and a toxic bacteria invades the lakes.
The bacteria emits a poisonous fume
that kills thousands
and causes even more to flee the area.
By 2070, people are coming back to find a changed watershed.
- Carpenter: In "Accelerated Innovation," we amplify
technology.
- In the "Accelerated Innovation" scenario,
society relies on technology
as a way out of environmental disaster.
But there is a trade-off:
more synthetic meats
and less emphasis on livestock.
- Carpenter: In "Nested Watersheds," we amplify
the role of governance.
- In the final scenario,
the boundaries and focus of government
is shifted towards water,
with water becoming a type of crop
to be harvested and sold.
The scenario stories are more than just conversation starters.
They are the fleshed out details of four possible futures.
The Yahara 2070 project
will support that flesh
with a skeleton of hard science,
which comes in the form of a state-of-the-art computer model
that allows the researchers
to answer all sorts of questions.
- Kucharik: What would water quality look like
50 years or 60 years from now?
What might crop yields look like?
How might we be able
to mitigate flooding
with better land management decision making?
- So what is this computer model?
Start with the water cycle,
the most basic concept
of how water moves through the environment.
When it rains, water can either
flow into the ground or into a lake or stream.
Some of that water evaporates
and becomes part of the next rainstorm.
The Yahara 2070 model
takes an action like rain falling on the ground
and then uses equations and algorithms
to determine how much soaks in and how much runs off.
And the computer models
more than just water.
- Kucharik: They represent cycles of how
carbon, water, energy, nitrogen, phosphorus
move through the system
from the atmosphere,
through plants,
through the soil,
through the ground water system,
and then, how those feed back
to the plants themselves.
- The computer model is thousands of lines of code,
all equations that deal with
different variables in nature.
- Kucharik: Where do those equations come from?
They came from people going out in the field and collecting data
and taking measurements.
- Eric Booth is an assistant research scientist
on the Yahara Project.
One of Booth's jobs in modeling the water cycle
is to learn just where the water goes
when it lands on the ground,
and how that's impacted by what's growing there.
- Booth: The corn is going
to behave a lot differently than switchgrass
when you have a one-inch rain event, for instance.
-Some of the water will be used by the plant to grow,
but some of that water will be given off by the plant later on .
- Sam Zipper: You always want to do a sunlit part of the leaf.
- Sam Zipper is a research assistant.
- Got a value of about
200 millimoles per square meter per second.
- Zipper uses a porometer
to see how much water is leaving this corn plant
in a process called "evapotranspiration."
- Zipper: Kind of looking at
how water moves from the soil into the atmosphere.
There's a continuum from the soil to the plant
and then moving up into the sky.
- Measuring individual corn stalks or leaves of grass
can be a tedious process,
but all water needs to be
accounted for in the computer model.
- This is one of the big parts of the water balance and
it's definitely the hardest one to get a handle on.
- Booth: We have several stations around the watershed
that are looking at
soil moisture
in a whole bunch of different land cover types.
We got forest, wetland,
a couple of corn fields,
grasslands,
even some urban areas, some turf grass.
- How water reacts in different environments
and in different parts of the growing cycle
will impact how water is handled by the computer model.
Booth needs to
map the groundcover across the whole watershed.
So, he takes to the air.
There is a generalized big picture to the Yahara Watershed.
Dairy dominates the north.
- Booth: We have a lot of livestock,
particularly in the upper part of the watershed.
- The lakes and the urban core sit in the middle.
- Booth: In the southern part,
it's mostly commodity grain farming.
- Booth breaks the Yahara Watershed
in to grid cells of about 12 acres,
and then determines what is growing in each cell.
He even factors in animals like cows
and how they impact the landscape.
This is where reality is first measured
and then converted into equations and computer code.
- Kucharik: It's that system of equations
that really go into making a more complex model
that represents the physics,
the chemistry,
the interactions of how things in an environment work together.
- Motew: This is computer code.
- Melissa Motew is
a graduate research assistant on the Yahara project.
- Motew: I'm making lots of graphs and animations and things
to help get an idea of what the numbers are saying.
- She's part of the team working on writing the code
that makes up the computer model.
Her graphs help her understand
if the model is producing accurate results.
- We're seeing what the model is generating, checking to see:
"Do these numbers make sense?
"Do they agree with what we've seen in the past?
What we understand from previous research?"
- You can go out and take fancy equipment
and collect a bunch of junk measurements.
- Professor Chris Kucharik says
the model is more than just a sum of their measurements.
- Researcher: 71.5...
- Kucharik: While everything is rooted in reality,
once you put all the equations together,
there's usually some type of uncertainty
when things start interacting with each other.
- They have to make sure the predictions of the computer model
matches reality.
This process is called "calibration and validation."
- Motew: So we have to test them against real observations.
- Validation is putting field data for past years
into the computer model
and seeing if the prediction matches what actually happened.
- We run simulations of the past
and then we compare the two.
- If the prediction doesn't match reality,
they have to calibrate or adjust the computer code.
- Motew: So then we go out,
and we might take measurements and refine our models
so that they better capture that process.
- The modeling group meets weekly
to compare results and troubleshoot.
- Kucharik: We probably spend
more of our time on calibrating
and validating these models.
- But even a fully calibrated and validated model
needs details.
How do you get field data from the future?
Without the computer model,
the scenarios are just stories.
Without a vision of the future provided by the scenarios,
the computer model is just a fancy algorithm.
So researcher Eric Booth is looking to the details
written in each scenario
to help him predict the landscape of the future.
- Booth: Okay, how are we getting energy in this scenario?
What are we eating in this scenario?
- To simulate the future presented in each scenario,
the team has to tell the model details
like what's being grown
and how much has the urban center expanded.
Each scenario story describes the severity of climate change,
and gives hints at the lifestyles of the people.
- Booth: We're just trying to follow
kind of the logical consequences
of what has already been decided in the story line.
- To demonstrate how lifestyle can influence land use
Booth turns to pizza.
Today, the northern part of the watershed
is dominated by dairy farming,
and a lot of that milk becomes cheese.
- Booth: A lot of the cheese that we make in this country--
and Wisconsin is obviously a big player-- ends up on pizza.
- As long as pizza remains
one of the most popular foods in America,
there will be a strong demand for cheese,
and therefore milk,
which means a lot of cows producing a lot of manure.
- Booth: That's connecting diet
to what we see on the landscape today.
- The "Abandonment and Renewal" scenario
calls for a mass exodus of people from the watershed
due to poisonous algae.
In that case, Booth predicts demand for milk and pizza
would go down and Booth has fewer cows on the map.
- Booth: What happens on a landscape just doesn't happen in a vacuum.
It's a reflection
of consumer demand for different food products.
- On the other hand, in the "Connected Communities" scenario
dairy demand remains high.
Booth has to calculate
the amount of manure those cows will produce
and the impact of growing corn to feed them.
- Booth: Each animal is going to produce
a certain amount of manure, on average, each year,
and in that manure is going to have
nutrients, phosphorus, and nitrogen.
- Booth even needs to estimate in the future
how much manure
is likely to be piped to digesters,
where the phosphorus is removed,
and how much gets spread on fields,
especially frozen fields, where it is much more likely
to run off in the lakes during the spring melt.
- We're certainly seeing the effects of phosphorus runoff
in poor water clarity.
- Which leads us back to Lake Mendota
and Professor Steve Carpenter.
- Carpenter: There is a tremendous amount of phosphorus
in our soils
and in the sediments of our streams
and in the sediments of our lakes.
- Phosphorus is a big focus of the study
because when it runs off in the lakes,
it leads to bigger algae blooms
and poor water quality.
- Professor Carpenter says
algae blooms are more than just a cosmetic issue.
Different types of algae
contain toxins known as cyanobacterium .
- Carpenter: The toxins, when they're present,
are quite deadly.
They are liver toxins
and brain toxins.
- Professor Carpenter says there is a connection
between our food choices as consumers
and water quality.
- Carpenter: The enabling factor is the continued runoff.
If these lakes were not so polluted with phosphorus,
we would not have to worry about toxic algae problems.
- While phosphorus runoff
is the oldest and most persistent threat
to water quality in the Yahara Watershed,
other threats like invasive species
are emerging.
- Carpenter: All right, let's see what we got.
Oh, yeah!
There are a lot of animals in here.
- Professor Carpenter is pointing
to a native water flea called "daphnia."
- Carpenter: Water fleas are really good at eating algae
so the water fleas actually improve water clarity.
- With plenty of algae to eat, daphnia should be abundant.
- Carpenter: Recently, this lake
was invaded by an animal called the "spiny water flea"
and the spiny water flea
eats the daphnia.
- Recent samples have shown
the daphnia population has dropped 95%,
and water clarity has gone down as well.
- Jiangxiao Qiu: So that's how they move.
See it here, it's like a snake movement.
- The invasive species
that could drastically alter the watershed
aren't just in the water.
- Monica Turner: They're known as the "Asian jumping worms"
or "Asian crazy worms."
- Professor Monica Turner
and her student assistant, Jiangxiao Qui,
are looking at how a new invader
can change the forest floor.
Their research shows crazy worms
eat through the top layer of the soil
twice as fast as the common earthworm.
Most of these invasive species are new to Wisconsin,
and no one knows what new species will come
between now and the year 2070.
- When we have a new invasive species show up in our area,
that may change things
in ways we don't even necessarily anticipate.
- The impact of invasive species
like crazy worms
will likely factor into a future computer model.
- Motew: And here we go...
- Meanwhile, the model created by the Yahara 2070 team
is ready to run now.
The team has estimated details like the climate,
ground cover,
and population growth
for each of the four scenarios,
and they've plugged
that hypothesized field data from the future
into the computer model.
- Motew: It is going to
now simulate every hour of every day
from the year 2014 to the year 2070.
We have 120 processors in this computer.
Each processor is simulating
a chunk of the Yahara Watershed.
- Each of the four scenarios
takes two days to simulate.
- Motew: All those pieces will be stitched together
into one gigantic dataset.
- Finally, they'll have results
and just one job left.
- Motew: Analyze the heck out of it.
- Researchers like Chris Kucharik want to make it clear
the results of the computer modeling
are closer to a forecast than a prediction.
- We're not trying to predict things.
We're trying to offer perspectives on,
"What are the plausible outcomes
"that might happen as a result
of these decisions that might be made?"
- The idea is to add data to the stories,
so the tradeoffs in the different scenarios
can be discussed through science, not speculation.
- Kucharik: If we go in this direction,
"What are the types of responses that we're likely to see?"
If we go in a different direction,
"What do the models suggest things might be like?"
- They might learn the stories in the scenarios
contain false assumptions.
- Motew: We don't actually know
if what's in the scenarios will play out.
So that's kind of one of our questions:
"How good are the assumptions there?"
- In fact, that ends up being
one of the major takeaways from the modeling results.
- One of these things doesn't look like the other, right?
- Melissa Motew presented the results on phosphorus
at a research symposium
for all the project members.
The models predict that
in all four scenarios
increasing climate change in the 2030s and 40s
will dramatically increase the levels of phosphorus
in the landscape and in the lakes.
In theory, as societal changes occur in the scenarios
leading up to the year 2070,
soil phosphorus should decrease.
- Motew: Three of these scenarios
are able to turn the corner,
they've reached their thresholds,
they're starting to come back down,
or at least to level off.
- The outlier is "Connected Communities."
That's the scenario that emphasized societal values
to improve the water quality.
The computer model says in 2070,
it has the worst phosphorus problem.
- Motew: We have "Connected Communities"
which is kind of running away.
- In the "Connected Communities" scenario,
people don't plant many cornfields
because they are prone to erosion.
This is an example of conventional wisdom
leading to unexpected results.
With corn, there is too much erosion
which leads to phosphorus in the lakes.
However, corn plants
take the most phosphorus out of the soil.
So without corn, too much phosphorus remains in the soil
and any erosion from flooding
leads to phosphorus in the lakes.
- Kucharik: Surprised, a little bit.
- Even more surprising is that
none of the big changes in the scenarios
made the water quality better than it is today.
- Kucharik: Even though the scenarios
were not designed to solve the water quality problems,
you'd like to think that those large-scale changes
would have had some immediate impact.
- Carpenter: I had expected that some of the scenarios
would show improvements and some would show things getting worse.
And in fact,
all of the scenarios are worse than today.
- The scenarios tackled the problem
through government,
technology,
abandonment,
and sustainable values.
Despite the differences,
the end result is nearly the same.
- Kucharik: There's just a long legacy
of buildup of soil phosphorus,
that seems to be overwhelming the system.
And when you superimpose changes in climate
on top of that,
it's kind of a one-two punch.
- Almost no matter how you manage phosphorus
in, say, 2050,
you've got big rainstorms
and all this phosphorus in the soil already,
and it's coming into the lakes and causing problems.
- This is more than just bad news for the year 2070.
While the scenarios assumed
the worst climate change would take place in the 2030s,
in reality
scientists say climate change is already underway.
- Kucharik: I think all of the best management practices
that have been going on in the watershed
in the last 30 years or so
have sort of held their own against the changes in climate,
but I'm worried we might be reaching a tipping point
where we sort of wear those effects out.
- Most efforts to battle phosphorus in the water
depend on activists and volunteers
who believe their efforts are making a difference.
- Carpenter: These projections
of water quality changes are bad
and potentially discouraging to people.
We're going to end up in a worse place pretty quickly.
- They hope the activists won't give up,
because despite the unexpected results,
Professors Kucharik and Carpenter
can see a silver lining.
- As a result of this project,
we have created a new generation of models
for understanding water quality
that are better than what we had before.
- Kucharik: Now we can start to use the modeling tools
to maybe design, come up with alternative scenarios
that might actually show
what you have to do to get to the point
that we want to be at in the future.
- The researchers say the next step
is to get the public and policymakers on board.
- Steve: I would like to see land use planning
taking a long view,
longer than the usual decade or so.
- Kucharik: There's a lot of things
that have happened in history
that you could never have thought would have happened
50 years into the future.
- Carpenter: Economic incentives could change.
The value of water could change.
- Now that they've developed the computer model,
they'd like to see what results
different scenarios could produce.
- Kucharik: A bigger question is:
"Is there a mosaic of land use, land cover that
"sort of gets us
our biggest bang for the buck?"
- The water quality problems took decades to build up,
and will likely take decades to solve.
- Carpenter: It'll be slow,
but over a generation or two, there could be big changes.
All right, let's see what we got.
- Professor Carpenter has dedicated his life
to studying lakes,
but over time, he's learned to expand his view
beyond the shore.
- You can't understand
the biology and ecology of a lake
without understanding
the priorities and values and activities
of the human beings around a lake.
- He hopes this project will help with that understanding.
- Carpenter: I think the efforts of this project
really will have long-lasting benefits.
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- Funding for Yahara Watershed: A Place of Change
was provided by
the Water Sustainability and Climate program
of the National Science Foundation.