Sea Level Rise
Embed Size (px)
Transcript of Sea Level Rise
Sea Level Rise
Sea Level RiseS1History of Sea Level Rise in Florida120,000 years ago 18,000 years ago Today + 6 meters - 120 meters
Source: H. Wanless, University of Miami2Causes of Sea Level RiseThermal expansion of waterMelting iceHuman change in land hydrology
Effects of Sea Level RiseFlooding and storm surgesDisplacement of humansSaltwater intrusionDisplacement of animalsGlobal plant and animal extinctionsLocal plant and animal extinctions
Picture: Green Lake, Austria. It is a park during the winter that floods every summer to form Green lake. It is complete with trails, benches, and bridges. 4The Earth is warming.
NASA figure adapted from Goddard Institute for Space StudiesSurface Temperature Analysis.
Despite ups and downs from year to year, global average surface temperature is rising. By the beginning of the 21st century, Earths temperature was roughly 0.5 degrees Celsius above the long-term (19511980) average. - http://earthobservatory.nasa.gov/Features/GlobalWarming/page2.php5Thermal 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.
6Glacier FormationGlaciers 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.
7Glacier Formation and RetreatChanges 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.8
Holgate Glacier July 24,1906National Snow and Ice Data Center/World Data Center for Glaciology. Grant, Ulysses Sherman. 1909 Holgate Glacier: From the Glacier Photograph Collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media. 9Holgate Glacier August 13, 2004
National Snow and Ice Data Center/World Data Center for Glaciology. Molnia, Bruce F. 2004 Holgate Glacier: From the Glacier Photograph Collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media.10McCarty Glacier July 30, 1909
National Snow and Ice Data Center/World Data Center for Glaciology. Grant, Ulysses Sherman. 1909 McCarty Glacier: From the Glacier Photograph Collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media.11McCarty Glacier August 11, 2004
National Snow and Ice Data Center/World Data Center for Glaciology. Molnia, Bruce F. 2004 McCarty Glacier: From the Glacier Photograph Collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media.
12Glacial Shrinking75% of the Earths 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.
Press play to show animation of glacier calving. Source: http://en.wikipedia.org/wiki/Ice_calving
Glacier Facts Source: http://nsidc.org/cryosphere/glaciers/quickfacts.html
Another source for last fact: http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-6.html13How much do melting glaciers contribute to sea level rise?
Between 1960 and 1990 glaciers contributed 0.37+/-0.16 millimeters per yearBetween 1990 and 2004 glaciers contributed 0.77+/-0.22 millimeters per yearBy the year 2100 glaciers are expected to contribute 240+/-128 millimeters per year.
The Glacier Contribution to Sea Level graph demonstrates how the contribution from melting glaciers began increasing at a faster rate starting in the 1990s. This is in agreement with high-latitude air temperature records. During the period 1960-1990, glaciers contributed 0.37 +/- 0.16 millimeters per year to sea level while during 1990-2004, the contribution increased to 0.77+/-0.22 millimeters per year (IPCC 2007). However, the latest predictions suggest possibly an even greater contribution by small glaciers and icecaps. Meier et al. (2007) conclude that with the current acceleration of glacier contribution to sea level rise, the total contribution from small glaciers and ice caps by the year 2100 is expected to be 240 +/- 128 millimeters, which represents an average annual increase of more than 2.0 millimeters per year. National Snow and Ice Data Center.
-http://nsidc.org/cryosphere/sotc/sea_level.html14How 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.
Image by Terry Haran, National Snow and Ice Data Center, University of Colorado, Boulder, using NASA MODIS data.
http://nsidc.org/cryosphere/sotc/sea_ice_mosaic.html15Albedo EffectThe 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.
This picture is being shown to compare the white reflective surface of ice and snow with the dark, heat absorbing surface of water.
Credit: NASA/Kathryn Hansen17Albedo EffectThis 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.18Human Change in Land HydrologyGroundwater depletionExtraction 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.UrbanizationIncrease in runoff due to increases in impermeable pavements and buildings.Prevents replenishment of groundwater.Deforestation and wetland drainingForest clearing increases runoff.Wetlands drained for agriculture and development.Reservoir storageDecrease sea level rise.Includes large stores of water such as dams.Overall contributionsTerrestrial 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.http://www.sciencedirect.com/science/article/pii/S0921818196000082http://www.nature.com/ngeo/journal/vaop/ncurrent/pdf/ngeo1476.pdf19