Sea Level Rise Magdalena Anguelova Ph.D. Student Advisor: Prof. Ferris Webster Sea Level Rise 5 min.
-
Upload
steven-williamson -
Category
Documents
-
view
223 -
download
0
Transcript of Sea Level Rise Magdalena Anguelova Ph.D. Student Advisor: Prof. Ferris Webster Sea Level Rise 5 min.
Sea Level Rise
Magdalena AnguelovaMagdalena AnguelovaPh.D. Student Advisor: Ph.D. Student Advisor: Prof. Ferris WebsterProf. Ferris Webster
Sea Level Rise
Sea Level Rise
5 min.5 min.
Sea Level Rise
2 of 22
Is Sea Level Rising?
Yes, the sea level is rising.
Sea level has risen about 4 to 8 inches (10 to 20 cm) over the past century.
Sea Level Rise
3 of 22
Rate of Rising
Sea level will continue to rise.
The important question is:
Will global warming
increase the rate of sea-level rise?
Sea Level Rise
4 of 22
Impact
Sea level rising will impact coastal areas:
» Coastline retreat;» Inundation of cities,
ports, and wetlands;» Beach erosion ;» Saltwater intrusion into
coastal freshwaters. Cape Henlopen Lighthouse, Lewes, fell in the sea in 1926
due to longterm shoreline retreat.
Sea Level Rise
5 of 22
» Several mm/yr fall in parts of Alaska.
Sea Level Along the U. S. Coast
Along most of the U. S. coast, sea level has been rising 2.5-3 mm/yr.
» About 1 cm/yr rise on the Louisiana Coast;
The rate varies:
Sea Level Rise
6 of 22
Factors Affecting Sea Level Rise
Postglacial rebound;
Global warming effects:Heat expansion of the ocean;Melting of mountain glaciers; Melting of Greenland and Antarctic ice
sheets.
Sea Level Rise
7 of 22
The Effects of Glacial Period
An enormous volume of water was removed from the oceans and was locked in ice sheets on the land.
Sea Level Rise
8 of 22
Glaciation Effects: Ice advancement
As the ice sheet advanced on the land...
Sea Level Rise
9 of 22
... the shoreline moved seaward.
Glaciation Effects: Displaced Shoreline
Sea Level Rise
10 of 22
Glaciation Effect: Ice Compression
The ice weight compressed the land downward.
And ...
Sea Level Rise
11 of 22
Glaciation Effect: Low Sea Level
... the sea level dropped about 130 m. Bangor,
Maine, is an example.
Sea Level Rise
12 of 22
Postglacial Rebound: Initial Flooding As the ice melted during the
deglaciation, sea level rose rapidly.
Bangor was flooded.
Sea Level Rise
13 of 22
Postglacial Rebound: Land Uplift
The land, unloaded from the massive ice sheets, started to uplift slowly.
Sea Level Rise
14 of 22
Postglacial Rebound
When the rate of land uplift exceeded the rate of sea-level rise due to ice melting, the seas retreated from the Bangor region
again.
Sea Level Rise
15 of 22
Postglacial Rebound
Since deglaciation, the Nordic countries have undergone an uplift of up to 250 m.
Postglacial rebound continues in Northern Europe.
Sea Level Rise
16 of 22
Global Warming Effects: Heat Expansion of the Ocean
With global warming, the temperature of the ocean would increase;
Like many other substances, seawater expands when heated.
Sea Level Rise
17 of 22
Global Warming Effects: Melting of Polar Ice
Ice at the North Pole is floating on the ocean and melting there due to global warming would not affect sea level.
Arctic Iceberg in Spring. Alaska, USA
Sea Level Rise
18 of 22
Global Warming Effects: Ice Sheets and Glaciers
Mountain glaciers and ice in Greenland and Antarctic are, thus, a cause for concern.
However, melting of ice resting on land would add to sea level.
Crowfoot GlacierBanff National Park, Alberta, Canada
Ice sheet in Antarctica
Sea Level Rise
19 of 22
Global Warming Effects: Mountain Glaciers
Mountain glaciers have been shrinking for the past century;
Glaciers on Mont Blanc Haute-Savoie, France
The water released into streams and rivers is being added to the sea.
Sea Level Rise
20 of 22
To Summarize…
The current sea level rise is due to:
» Thermal expansion -- about 5 cm (2”);
» Melting of small glaciers
and the ice edges of Greenland and Antarctica -- another 5 cm.
Sea Level Rise
21 of 22
Possible Sea Level Fall Antarctic ice may accumulate and lower sea level.
Global warming might melt the ice at the edges of Antarctica.
But warm air will carry more moisture, which will then precipitate as snow in the interior of Antarctica.
Snow petrels resting on a large iceberg near Adelaide island, Antarctic.
Sea Level Rise
22 of 22
What to Expect?
About 70 cm!
A possible rise over the next century is
from:» Small glaciers melting -- about 40 cm;» Thermal expansion -- about 30 cm.
The EndThe End