Sea Level Rise

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.