1.  Sea Level Rise

2. History of Sea Level Rise in Florida 120,000 years ago 18,000 years ago Today + 6 meters - 120 meters

3. Causes of Sea Level Rise  Thermal expansion of water  Melting ice  Human change in land hydrology

4. Effects of Sea Level Rise  Flooding and storm surges  Displacement of humans  Saltwater intrusion  Displacement of animals  Global plant and animal extinctions  Local plant and animal extinctions

5. The Earth is warming….

6. Thermal Expansion of Water  Water is a molecule made up of one Oxygen atom and two Hydrogen atoms.  As water is heated, the particles begin to move more and more.  The particles take up more space and the average separation between particles increases.

7. Glacier Formation  Glaciers are sheets of snow and ice.  Form where there is more snow in the winter than what is lost during the summer.  The pressure of building snow layers creates ice and causes glaciers to move very slowly.  Glaciers move through valleys, like rivers, or spread out in all directions due to the force of gravity.

8. Glacier Formation and Retreat  Changes in glaciers are studied by scientists as indicators of climate change.  Changes usually occur over hundreds to thousands of years.  Recent observations of glaciers show a tendency towards shrinking over the last 60-100 years.

9. Holgate Glacier July 24,1906 National Snow and Ice Data Center/World Data Center for Glaciology.

10. Holgate Glacier August 13, 2004 National Snow and Ice Data Center/World Data Center for Glaciology.

11. McCarty Glacier July 30, 1909 National Snow and Ice Data Center/World Data Center for Glaciology.

12. McCarty Glacier August 11, 2004 National Snow and Ice Data Center/World Data Center for Glaciology.

13. Glacial Shrinking  75% of the Earth’s freshwater is locked in glaciers.  Glacierized areas cover 5.8 million square miles of land.  As glaciers retreat, melted freshwater is deposited in the ocean.  Large chunks of ice can break off of glaciers and fall into the ocean (this process is called calving).  If all land ice melted, sea level would rise approximately 230ft world wide.

14. How much do melting glaciers contribute to sea level rise?  Between 1960 and 1990 glaciers contributed 0.37+/-0.16 millimeters per year  Between 1990 and 2004 glaciers contributed 0.77+/-0.22 millimeters per year  By the year 2100 glaciers are expected to contribute 240+/-128 millimeters per year.

15. How does melting sea ice affect sea level rise?  Unlike glaciers which are on land, sea ice is floating in the ocean.  When sea ice melts it does not significantly change sea level because it is already in the ocean.  However when sea ice melts it increases the rate of warming in the artic.

16. Albedo Effect  The white color of the ice reflects heat...  While the dark, almost black color of the ocean absorbs heat.  This is called the ice-albedo effect.

18. Albedo Effect  This increases the warming as the climate becomes warmer...  and increases the cooling effect as the climate becomes cooler.  This is has occurred during many ice ages and interglacial periods in the past.

19. Human Change in Land Hydrology  Groundwater depletion  Extraction of groundwater at rates that exceed the natural rates of replenishment.  Most water that is withdrawn is consumed by humans and animals, evaporated, or transpired, the rest contributes directly to to sea level rise.  Urbanization  Increase in runoff due to increases in impermeable pavements and buildings.  Prevents replenishment of groundwater.  Deforestation and wetland draining  Forest clearing increases runoff.  Wetlands drained for agriculture and development.  Reservoir storage  Decrease sea level rise.  Includes large stores of water such as dams.  Overall contributions  Terrestrial water use contributes about.77 mm/yr. of sea level rise according to the latest scientific research (2012).  Most significant contributors are groundwater depletions and artificial reservoirs for water storage.