Title: Climate Change and the Ocean
1Climate Change and the Ocean
2The Greenhouse Effect
http//www.ucar.edu/learn/images/gheffect.gif
3Global Warming
- Increase in the average temperature of the
biosphere
http//meteo.lcd.lu/globalwarming/hockey_stick/man
n_hockeystick.jpg
4Increase in Average Temperature
- The average temperature worldwide is 58?F
- 5 increase means
- Only 1-2? at the Equator
- More than 12 at the North Pole
5What causes Global Warming?
6 The Carbon Cycle
7http//gis1.ucsc.edu/ericw/co2percap1998p.gif
8Visual of rising temperatures and CO2
concentrations from An Inconvenient Truth
9Threats to the OceanRelated to Global Warming
- Changes in sea surface temperatures
- Melting Polar Ice Caps
- Coral Bleaching
- Thermohaline Circulation
- Extra CO2
- Rising Sea Level
10Seawater Chemistry
- Ionic Bond-attraction between ions that have
opposite charge - Ionic bonds between Cl and Na
- Sodium and chloride are the two most abundant
ions
11Properties of Water
- Water is densest at 4?C
- Hot water floats and cold water sinks
- Ice floats
- Surface tension makes water sticky
- Up-wellings
12Polar Molecule
- Water is a polar molecule
- It has a negative side and a positive side
- This allows water to easily dissolve ionic
compounds
13http//news.nationalgeographic.com/news/2006/09/06
0914-arctic-ice.html
14Positive Feedback
http//forces.si.edu/arctic/02_02_00.html
15The Arctic Ocean could be ice free in summer by
2050.
- Arctic Climate Impact Assessment. 2004. Impacts
of a Warming Arctic. Cambridge, UK Cambridge
University Press.
16 The number of Category 4 and 5 hurricanes
has almost doubled in the last 30 years.
- Emanuel, K. 2005. Increasing destructiveness of
tropical cyclones over the past 30 years. Nature
436 686-688
17http//www.fws.gov/home/hurricane/katrina-nasa.jpg
18http//www.ci.huntington-beach.ca.us/images/users/
fire/Hurricane20Katrina20Response3.jpg
19Coral Reefs in Danger
- 2005, the hottest year on record
- Massive loss of coral reefs
- 1998, 2nd hottest year on record, lost 16 of
coral reefs - Coral bleaching occurs when little, colorful
algae living within the coral are stressed by
heat and other factors. They are then forced to
evacuate and this reveals the colorless calcium
carbonate skeleton. - Pollution, dynamite fishing practices, more
acidic ocean watersbut rising ocean temperatures
is causing the most damage.
20The link between global warming and large-scale
bleaching of corals, considered controversial
only 10 to 15 years ago, is now universally
accepted.
21Acid-Base Balance
An acid is a substance that releases a hydrogen
ion (H) in a solution. Acidity is caused by an
excess of H ions. A base is a substance that
combines with a hydrogen ion (H) in solution.
Alkalinity is caused by an excess of OH-
(hydroxide) ions. The acidity or alkalinity of a
solution is measured by the pH scale.
22The pH Scale
23pH of Seawater
The ocean has an average pH of 8.0, meaning it is
slightly alkaline. Note that the pH of seawater
varies slightly with depth.
24Dissolved Gases in Sea Water
- Gases dissolve more readily in cold water than
in warm water. - O2 and CO2 levels are controlled mostly by the
activity of living things. - N2, O2 and CO2 - most common gases in seawater
- Photosynthesis by plants and phytoplankton
produces oxygen and uses up carbon dioxide. - Respiration by animals, bacteria, and other
organisms produces carbon dioxide and uses up
oxygen.
25Dissolved Gases in Seawater
- The figure shows how O2 and CO2 levels vary with
depth. - Photosynthesis by plants at the ocean surface
causes high levels of O2 and low levels of CO2. - Below the surface where there is not enough light
for plants, respiration by animals causes lower
levels of O2 and higher levels of CO2.
26Increasing CO2 Concentrations
- 33-50 of CO2 emissions sink into the ocean where
it converts to calcium carbonate - CO2 turns into carbonic acid which changes the pH
of the ocean. - Increases the acidity of the water and slows down
calcification - Could cause the ocean to be more acidic than the
last 800,000 yrs - Reduces the ability to absorb more CO2
- Impact on organisms with shells, plankton, coral
reefs?
27Al Gore on Ocean Acidification
28More than a million species worldwide could be
driven to extinction by 2050.
- Time Magazine, Feeling the Heat, David Bjerklie,
March 26, 2006
29http//www.spiegel.de/img/0,1020,29758,00.jpg
30Polar bears and climate change from Planet Earth
- http//www.youtube.com/watch?vqpob8_jAyVU
31http//www.geekculture.com/joyoftech/joyimages/956
.gif
32What causes currents?
- Wind (surface currents)
- Salinity
- Temperature
- Gravity
- Topography
- Earths rotation
33Salinity
- The total quantity of dissolved inorganic solids
in water. - The most abundant dissolved solids are chloride,
sodium, and sulfate.
34Salinity
- Oceanographers more commonly measure salinity as
parts per thousand (ppt) - In the ocean the average is around 35 ppt
- Measured using a refractometer
35http//www.bgrg.org/pages/education/alevel/coldenv
irons/Gulf20Stream20Map201.gif
36European Ice Age
- 10,000 years ago, when the last glacial ice sheet
in North America melted, it formed a giant pool
of fresh water (forming the Great Lakes) It was
held in place by a giant ice dam. - The ice dam broke and the freshwater rushed into
the Atlantic. This caused the Gulf Stream to stop - Europe no longer received all of the heat from
the evaporating Gulf Stream and went into an ice
age for 900-1000 years. - Scientists concerned about the rapid melting of
ice in Greenland
http//www.whoi.edu/page.do?pid12455tid282cid
17906
37Local Issues
- Warmer sea water pushes cod and lobster north to
cooler waters. - In 2005, NH brought in more than 14 million in
lobster and 1.9 million in cod - Concern about NHs coastline
- Concord Monitor July 12, 2007
http//www.dirnat.no/multimedia.ap?id32407
38Salt Marshes
- Sea level change of 2 feet would inundate New
Hampshires salt marshes and beaches
39Sea Level Prediction of IPCC
- In the Intergovernmental Panel on Climate
Changes most recent report they predict - Sea level rise between 19-58 centimeters by 2100
- But many scientists argue that this is an
underestimate - Many think that the sea-level rise will be close
to the worse-case predictions
40Global sea levels could rise by more than 20
feet with the loss of shelf ice in Greenland and
Antarctica, devastating coastal areas worldwide.
- Washington Post, "Debate on Climate Shifts to
Issue of Irreparable Change," Juliet Eilperin,
January 29, 2006, Page A1.
41 42How can we influence climate change with the
choices we make everyday?
43Homework assignmentDue Tuesday
- What havent we talked about? Research an
additional threat to the ocean because of climate
change that wasnt mentioned in class. - Please summarize your ocean threat in a paragraph
and cite the resource that you used.