Water is life YOU are 60% water and can only live a few days without drinking water
Water & Culture Indigenous cultures “recognize, honor and respect water as sacred and sustains all life” www.indigenouswater.org/user/IPKyotoWaterDeclarationFINAL.pdf Water is the blood of mother earth, the giver of life Water is worthy of reverence and great respect
Water & Culture Water plays a central role in most indigenous cultures There is a Tohono O’odham song that describes how the red ripe fruit of the saguaro call to the clouds to form overhead. These clouds mark the beginning of the summer monsoons and also the beginning of the new year in the traditional Tohono O’odham calendar
Water and society Water shortage predicted to become THE major crisis in our future Over 50% of the world’s population does not have an adequate supply of safe drinking water
WATER & SOCIETY Water shortages are due to the growing human population on Planet Earth
Human Population History WATER & SOCIETY
Part II: HYDROLOGIC CYCLE
Hydrology Water distribution 70% of the Earth’s surface is covered with water
Hydrology Water distribution 70% of the Earth’s surface is covered with water BUT 97.5% of this water is salt water
Only 2.5% of the planet’s water is freshwater, and only 1% of that exists on Earth’s surface
79%=ice caps and glaciers
Matter Recycling in Ecosystems Law of Conservation of Matter: matter is neither created nor destroyed. Just moved around and transformed. Biogeochemical cycles: the movement of chemicals through the components of the Earth system. These components are also called “biogeochemical reservoirs”. 13
components of the Earth SYSTEM Lithosphere: the solid Earth; land
components of the Earth SYSTEM Lithosphere: the solid Earth; land Hydrosphere: the liquid Earth; water
components of the Earth SYSTEM Lithosphere: the solid Earth; land Hydrosphere: the liquid Earth; water Atmosphere: the gaseous Earth; air
components of the Earth SYSTEM Lithosphere: the solid Earth; land Hydrosphere: the liquid Earth; water Atmosphere: the gaseous Earth; air Biosphere: living things (organisms)and the parts of the lithosphere, hydrosphere, and atmosphere in which things live
components of the Earth SYSTEM Lithosphere: the solid Earth; land Hydrosphere: the liquid Earth; water Atmosphere: the gaseous Earth; air Organisms: living things Cryosphere: frozen or solid water such as ice caps, glaciers, snow and permafrost
HYDROLOGIC CYCLE Hydrologic cycle Cycling of water in and out of atmosphere and between all the earth’s components. All of the water on our planet is recycled and a given molecule of water is used over and over throughout time. Water is the primary medium by which energy and matter move are circulated through the Earth system components. 19
The hydrologic cycle
Water enters the atmosphere by evaporation and by transpiration from leaves.
It condenses and falls from the atmosphere as precipitation.
When water falls as precipitation on land, it has two possible pathways:
Returns to the hydrosphere by flowing as runoff from the land surface into streams, rivers, lakes, and eventually the ocean. Returns to the lithosphere by infiltration into the ground becoming soil water or ground water.
Hail fog Hail fog Hail fog Hail fog Hail fog Hail fog Precipitation - Any form of water that falls to Earth from the atmosphere
Water appears in all 3 of its phases at different times during the hydrologic cycle Solid
Ice, hail, snow, glaciers, ice caps etc.
Water droplets, including clouds, lakes, streams etc.
- - - - - - - - - O O O O O O O O O + + + + + + + + + + + + + + + + + + H H H H H H H H H H H H H H H H H H Water Vapor
- - - - - - - - - O O O O O O O O O + + + + + + + + + + + + + + + + + + H H H H H H H H H H H H H H H H H H Water Condensation
FIVE PROCESSES OF THE HYDROLOGIC CYCle Precipitation: Any form of water falling from the atmosphere to the ground. Condensation: The process of changing from a gas to a liquid Evapotranspiration: Evaporation: the transformation of water from liquid to gas phases as it moves from the ground or bodies of water into the overlying atmosphere. The source of energy for evaporation is primarily solar radiation Transpiration: the release of water vapor from plants into the atmosphere. Evaporation + transpiration=evapotranspiration
Infiltration and run-off Run-off: variety of ways water moves across the land
Snowmelt: run off from melting of snow on mountain tops
Water can flow to rivers, lakes, reservoirs, oceans or infiltrate into soil
Infiltration: flow of water from surface into the ground
Once in ground can become soil water or ground water
Hydrologic Cycle Powered By: & Solar Energy (evaporation)
So, where does water go when it falls on earth? about 76% lost to evaporation 32% run-off small percent infiltrates into groundwater
LE 3-16 Food for thought… Where does the hydrological cycle begin and end? Atmosphere 13,000 Evaporation 425,000 Precipitation 111,000 71,000 Ice caps, glaciers, and snowfields 33,000,000 Precipitation 385,000 Evaporation Transpiration Rivers Extraction Runoff 40,000 Land plants Uptake Human use Infiltration <11,000 Water table Extraction Soil water 122,000 Oceans 1,350,000,000 Aquifer Groundwater 15,300,000
QUESTION: Testing Your Comprehension Water enters the atmosphere through the process of…? a. Precipitation b. Transpiration c. Infiltration d. Runoff
QUESTION: Testing Your Comprehension Water enters the atmosphere through the process of…? a. Precipitation b. Evaporation c. Infiltration d. Runoff
QUESTION: Testing Your Comprehension Water enters the lithosphere through the process of…? a. Precipitation b. Transpiration c. Infiltration d. Runoff
Part IiI: HYDROLOGIC CYCLE & climate
Climate Concepts: rise or sink Warm air rises Open the oven, you feel the heat on your face Cold air sinks Open the freezer, you feel the cold at your feet
Warmer Air Cooler Air Equal Air Temp Cooler Air Warmer Air Equal Air Temp Statically unstable Statically neutral Statically stable http://science.howstuffworks.com/hot-air-balloon.htm
Climate Concepts: rise or sink When air rises, it cools Top of mountain is cooler than the base of the mountain. When air sinks, it warms The base of the mountain is warmer than the top of the mountain.
Climate Concepts: warm or cold Warm air holds more water Cold air holds less water
Climate Concepts: water in air As air rises, it cools Cooler air holds less water vapor. If it gets even cooler, then it rains RISING AIRRAIN
Climate Concepts: water in air As air descends, it dries warmer air holds more water vapor. As air dries, it is less likely to rain DESCENDING AIRDRY
Climate Concepts: water in air The temperature to which the air had to cool to become totally saturated is called: Dew point: the temperature at which the relative humidity = 100%
Dew Point The temperature at which dew (condensation) begins to form Dew is the water you find on your grass or car early in the morning. Frost is when water is deposited as small ice crystals. Frozen dew is liquid dew that freezes. If the temperature reaches the dew point temperature, then dew (or frost) will form. http://apollo.lsc.vsc.edu/classes/idm3020/tut_folder/nick_tutorial/
Climate Concepts: Review Warm air holds (more or less?) water vapor; cold air holds (more or less?) water vapor. As air cools down, the chance of rain increases or decreases? As air rises, the chance of rain increases or decreases?
What causes Precipitation?
Rain = moisture + cooled down air
No Rain = low moisture and/or heated up air
Hydrologic cycle & climate Solar radiation is most intense at the equator for two reasons: 1) the sun’s rays are concentrated in a smaller area 2) the sun moves through less atmosphere
Hydrologic cycle & climate Tropics are hot
Hydrologic cycle & climate Hot air rises
Hydrologic cycle & climate Air cools asit rises; sinks30°N and S
Hydrologic cycle & climate Each convectioncell is called aHadley Cell
Hydrologic cycle & climate Descending air at30°N & S is warmand dry
30th Degree Latitude Deserts 30th degree N & S are areas of sinking air / areas of high pressure
HYDROLOGIC CYCLE & CLIMATE CHANGE
Scientists have measured an intensification of the hydrological cycle due to global warming:
Globally, the average atmospheric water vapor concentrations have increased.
It is predicted that this will lead to increased precipitation rates in some areas.
The largest increases in precipitation are expected to occur near polar regions, for two reasons.
One, observations and climate models indicate that the warming rate has been and will continue to be the highest there, and warmer air can hold more water vapor.
Two, the warming will reduce the extent of sea ice , thereby allowing more evaporation from open water.
Cycles of wet and dry periods are normal, however, When the hydrological cycle is out of balance (or intensified due to climate change), these can lead to more extreme flooding and drought cycles
HYDROLOGIC CYCLE SUMMARY
Cycling of water in and out of the atmosphere and between all the earth’s components.
Water evaporates from the surface of the earth, rises and cools, condenses into rain or snow and falls again to the surface. The water falling on land collects in rivers and lakes, soil, and porous layers of rock, and much of it flows back into the ocean.