"Nibi" means "water" in the language of the Lake Superior Ojibwe people. Nibi is sacred.
In this unit you will investigate the impacts of a warming climate on water and how these changes affect cultural, environmental, and economic practices that rely on water. You will discover water’s role in climate change and how climate change affects water.

Water is important in many cultures. It is critical for life. Without water, living things cannot survive. We are made of 95% water. Water is important to our health, environment, economy, and our communities. Water connects us to all living beings.  

Too often we take clean, abundant water for granted.  We rarely think about water unless there is too much of it when we have floods, or too little of it when there are droughts. 

Since everything on earth depends on water, the interaction of climate change and water affects everything. As you work through this unit, think about how these changes may affect you.

Listen carefully, the water is speaking!  
Key indicator: "Nibi" (water)

Possible climate change stressors: Higher temperatures; changes in type of precipitation, amount, and intensity

Impacts include:
Warmer atmosphere, increased water temperature, increased storm events, drought, changes in rain and snow; loss of glaciers, ocean becoming more acidic sea level rise

How long can you live without the following:
Food?...   3 weeks
Electrical power? …. Weeks to years
Your cellphone?... Indefinitely
Water?....   3 days

  • Understand the water cycle and role of water vapor as a greenhouse gas in global warming
  • Identify specific stressors that affect the water cycle and how these change the type and amount of precipitation we receive
  • Understand where the water you use is coming from
  • Develop and test a hypothesis to determine how climate change is affecting precipitation in Wisconsin and how these changes are affecting ecosystems and cultural practices that rely on water
  • Implement a service learning project to educate others about how to reduce climate change impacts.


How old is the water in your water bottle?  It’s old as the earth itself!  Chances are the water you are drinking was once part of an ocean, a glacier, or even a cloud.  That’s because earth has a limited amount of water.  

Water comes in three forms:  water vapor (gas), rain (liquid), and snow (solid).   Water is always moving between these forms through an endless circle called the water or “hydrologic” cycle. What powers this cycle?  The sun’s heat!  

As liquid water on Earth warms, it can change form from into water vapor. This is called “evaporation.” Water evaporates from a river, lake, or ocean and enters the atmosphere. Even though we can’t see it, the sky can be full of water! 

When atmospheric water vapor is cooled, it changes back into its liquid form as tiny droplets. This is called condensation.   We see it as clouds or fog.  When the atmosphere gets so full of water that it can’t hold it any longer, it falls back to earth surface as precipitation in either rain (liquid) or if temperatures are cold enough as snow or ice (solid).  The cycle starts again as this water is evaporated back into the atmosphere.

Water also moves through Earth and is stored here. Some soaks deeply into the Earth and is stored as “groundwater.”  Precipitation that falls in very cold regions can be stored as glacial ice. If there is too much precipitation at one time, water runs off the land can cause flooding and erosion.  

We are part of the water cycle, too. Every time we breathe, we exhale water molecules into the atmosphere. Plants are “breathing” too. They pull in water through their roots and “exhale” water vapor through their leaves. This is called “transpiration.”

Water is always on the move above and through the Earth and all living things! What comes around, goes around when it comes to water. 

The Water Cycle--What comes around, goes around!

Did you know that water is more than a habitat for fish or a great place to swim?  Water plays an important role in global warming. 

Water is one of the “greenhouse gases” that form a protective blanket around the Earth. These gases include:
  • carbon dioxide (CO2),
  • oxygen (O2),
  • nitrous oxide (NO2),
  • methane (CH4),
  • and water vapor (H2O).  

When these greenhouse gases are in balance, they act like a blanket trapping just enough of the sun’s heat to keep the Earth warm. We need greenhouse gases. Without them the Earth would be an ice ball in space!  But just like putting on too many blankets, higher concentrations of greenhouse gases can trap too much heat, adding extra warming to the Earth.

What is the most abundant greenhouse gas?  It’s water!  Water vapor makes up almost 90% of Earth’s greenhouse gases.  It comes from evaporation of liquid water from water bodies on earth, like the ocean.  The warmer the atmosphere, the more water vapor it can hold.  Even though it’s the most abundant greenhouse gas, atmospheric water vapor only sticks around for a short time before it falls back to Earth as rain or snow!

The percentage of carbon dioxide (CO2) in the atmosphere compared to water vapor is much smaller. Why is the impact of CO2 greater?  Because unlike the other greenhouse gases, CO2 accumulates in the atmosphere where it can last up to 200 years.  More CO2 in the atmosphere adds to the greenhouse gas “blanket”, trapping more heat and warming the Earth.  Atmospheric CO2 comes from natural sources such as when plants decompose, from the oceans, and when we breathe.  But evidence shows that human activities, such as burning of fossil fuels, deforestation, and land use are increasing atmospheric CO2 levels. 

When it comes to climate change water vapor may sound pretty harmless, but acting with CO2 water vapor can create a vicious cycle called a “positive feedback loop” that increases warming. Here’s how this works:

When more CO2 is added to the atmosphere, temperatures warm due to greater amounts of heat trapping CO2. Warmer temperatures cause more water to evaporate into the atmosphere. Because water vapor is a greenhouse gas, once it is in the atmosphere it increases the “blanket” effect around the Earth causing more warming.  More warming encourages more evaporation, amplifying the warming effect caused by CO2.  According to NASA scientists,  "We now think the water vapor feedback is extraordinarily strong, capable of doubling the warming due to carbon dioxide alone."

Think of CO2 as the dial on Earth’s atmospheric thermostat.  The water vapor feedback loop actually makes temperature changes caused by turning up the Earth’s CO2 levels or "dial" even higher. Investigate more about the role of water vapor and climate change here

Water, water, everywhere?  Well, not really!

The distribution of water on the Earth's surface is extremely uneven. Only 3% of water on the surface is freshwater—the kind we need to survive. The rest (97% ) is salt water oceans.  Of the freshwater, 99% is in storage. It’s either frozen solid in glaciers or held deep underground as groundwater. That leaves less than 1% of freshwater is readily available as surface water in lakes, rivers and swamps.

The freshwater water you use comes from a watershed.  Each of us lives and works in a watershed. 

Like a big bathtub, a watershed is an area of land where all water within it eventually flows out to a common “drain”, such as a river, lake, or ocean. The boundaries of a watershed are higher places, such as hills or mountains, work like the sides of the tub. Rain, snow, groundwater, and even pollution that fall within watershed eventually drains to the river, lake, or ocean. 

Watersheds provide a variety of important environmental “services”. A watershed’s surface waters like rivers and lakes provide habitat for fish, plants and wildlife. Adjacent wetland areas provide habitat, filter pollutants, and slow the flow of runoff. A underground layer of rock that contains or allows water to pass through it are called "aquifers." They provide drinking water for our communities. Our economy runs on water. We need it for agriculture, industry, energy production, and life!.

A healthy watershed can “slow the flow” of water and reduce flood and storm damage. This allows more water to soak into the ground, rather than running to and causing erosion. 

Water and watersheds connect us. Think of your watershed like a neighborhood. What happens in your yard, and your neighborhood’s yard, in the streets, and in parking lots of your city affects the health of your local watershed and the water supplies.

A changing climate affects will affect the amount and quality of water within your watershed. What affects your local watershed also affects the global water system because it’s a big cycle.


Rising Air and Water Temperatures:  Air temperature has a direct effect on increasing water temperature and evaporation of water from lakes and rivers. For example, brook trout which are a cold water loving species, are expected to be hit hard if Wisconsin’s climate warms and stream temperatures rise. Climate models predict up to 95% of brook trout habitat across Wisconsin could be lost if the average annual summer air temperature increased just over 5 º F.  Hotter days also mean less soil moisture, more evaporation, and less groundwater recharge to replenish water levels in streams and lakes. This can also affect municipal drinking water supplies. Lower water levels will affect navigation which impacts shipping, recreation, and public safety. Warmer water temperatures can favor invasive species that can outcompete native species. Warmer water temperatures are favorable to toxic organisms like blue-green algae. 

Increase in Intense Rain and Storm Events: A warmer “juiced up” atmosphere can hold more water vapor and intensity rainfall events.  Intense storms cause flooding can damage private property and public infrastructure and affect buildings, electrical systems, roads, bridges, and municipal water systems.  These are costly repairs. Flooding and erosion from intense storms can destroy fish and wildlife habitat. Intense heavy rainfall events can wash away fish nesting areas and fish eggs, or cover them with sediment and silt. 

Drought: While the intensity of rainstorms is projected to increase, so is the frequency of localized periods of extreme drought caused by an increase of days over 90-degrees F. Stream flow and lake levels may be lowered. Important aquatic habitats and vegetation within the shallower littoral zone that provide spawning, feeding, and resting areas could be reduced or eliminated. 

Changing Precipitation:  Even through climate change models project that in Wisconsin there will be more rainfall over (especially as rain falling during winter months due to warmer temperatures) the forecast is that there will not be enough precipitation to balance the higher rate of evaporation due to higher summer temperatures. Summer lake and stream levels are predicted to be lower. This will impact the amount and quality of aquatic habitats available for fish. 

Shorter, Warmer Winters:  This might sound good to some people, but consider how important snow is to Wisconsin’s environment and economy. Wildlife species, like the American Marten, rely on deep snow habitats. Shorter winters result in more evaporation and water loss from rivers and lakes. Why? Because ice on a lake blocks the evaporation of water from its surface. The lack of ice allows evaporation from lakes even during the winter resulting in lower lake levels.  

Global Climate Related Impacts:

Melting glacial ice:  Warmer temperatures will affect water that has been locked in long term storage as glacial ice. Melting glacial ice releases water into Earth’s systems, raising sea levels. There may not be a glacier in your backyard, but if you live on coast, sea levels are rising due to climate change. This is already causing flooding in coastal areas. Investigate more about this issue here

Rising Sea Levels: Water becomes less dense and expands when it is warmed. As global temperatures go up, oceans will get warmer and their waters will expand. This is called "thermal expansion." Together with the additional water from melting glaciers, thermal expansion of the ocean will contribute to sea level rise. This will threaten coastal communities and productive near-shore coastal habitats. Investigate more about this issue here.

Ocean Acidification: Oceans absorb about a quarter of the CO2 emitted each year. The CO2 reacts with seawater to form carbolic acid. The ocean is now 30% more acidic due to the amount of CO2 that has been absorbed. More acidic seawater prevents marine animals, like corals and oysters, from building the shells they need to survive.  This affects the health of coral reefs that are nurseries for marine life and threaten commercial fisheries. Investigate more about this issue here