Understanding the Polar Regions and Climate Change

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• Understanding the Polar Regions and Climate Change

Presented by Julie Brigham-Grette
SSEC U Wis-Madison
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Outline -- Why are the Polar Regions Important to
Everyone?
Geography of the Poles Oceans, land, and
ice Definition of the Arctic/Antarctic Tilt of
the Earth Cause of Seasons Changes in Day
Length Earth in the Balance Cryosphere sea
ice/albedo Ocean Circulation and Heat
Transport Thermohaline Circulation The Changing
Polar Regions Marine Transportation Greenland A
laska Antarctica Carbon Dioxide
Bjerknes Center image, Bergen
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Geography of the Poles
Google Earth
Deep Ocean surrounded by Land and worlds largest
continental shelves
Continent landmass covered with glacial ice
surrounded by Ocean
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Geography of the Arctic
http//www.gebco.net
Average depth of Arctic Ocean 1038 meters
(3407 ft) Deepest point in the Eurasian
Basin 5450 meters (17,881 ft). Entire basin
1.5 times the size of the contiguous US Best
known for its ice cover!
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Geography of the Arctic
Earths north pole is in the Arctic Ocean over
the deep Eurasian Basin 60 of the Arctic ocean
is underlain by shallow continental shelves --
the widest in the world!!
www.ngdc.noaa.gov/mgg/image/IBCAO_betamap.jpg
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Geography of the Arctic
Greenland Ice sheet If it melted, the water
would return to the sea and raise global sea
level 6.5 m (21 ft.)
Image ACIA
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Geography of the Arctic
Whiteness! Ice and snow
Map ACIA images Karen Frey
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Geography of the Arctic
Contrasts in landscapes
Photos Julie BG
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Geography of the Arctic

Vegetation Contrasts
Boreal forests of birch, spruce
Treeline ecotone
Open Tundra
Photos Bob Nelson, Colby College
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Geography of Antarctica
NASA/Goddard Space Flight Center Scientific
Visualization Studio
Average height of Antarctica 2438 meters (8000
ft) Highest point Vinson Massif 4897m high
(16067ft) Entire continent 14 M km2 1.5 times
the size of the entire US
http//www.scar.org/information/statistics/
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Geography of Antarctica
High Coastal Mountains High Ice Sheet Plateau
and Dry
Images Ross Powell, NIU
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Geography of Antarctica
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Geography of Antarctica
Driest Place in the World
Images Ross Powell, NIU
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Geography of Antarctica
If it melted, the water would return to the sea
and raise global sea level 65 m (213 ft.)
8 m (26 ft)
Ice flow velocity
British Antarctic Survey
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Geography of Antarctica
Polar Glaciers
Images Ross Powell, NIU
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Defining the Arctic
Earth has an axial tilt of about 23.44.
90-23.44 67.66 So, Arctic Circle at 67.66N.
http//en.wikipedia.org/wiki/ImageAxialTiltObliqu
ity.png
Were always tilted in the same direction
throughout the year.
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Defining the Arctic/Antarctic

• As the Earth orbits the sun, the seasons are
  determined by the Earths tilt.

http//www.windows.ucar.edu/tour (seasons)
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Defining the Arctic/Antarctic

• Effect of different sun angles
• Summer solstice sun is more concentrated per sq m
• Hot weather on the way

Suns rays spread over a wide area
Suns rays spread over a narrow area

• Winter solstice sun is less concentrated/ spread
  out
• Cooler weather

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When the Sun is directly overhead, its rays
strike Earth perpendicular to the ground and so
deliver the maximum amount of energy. When the
Sun is lower in the sky, a sunbeam strikes the
ground at an angle (in the example above, 45?)
and so its energy is "spread out" over a larger
area... thus "diluting" its energy. In this
example, the energy is spread over an area of
1.41 square meters (instead of 1 square meter
when the Sun is directly overhead), so the energy
per unit area is reduced from 342 W/m2 to 242
W/m2 (342 ? 1.41 242).?Credit Artwork by Randy
Russell. (www.windows.ucar.edu/tour (sun
radiation)
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http//www.windows.ucar.edu/tour/link/earth/clima
te/sun_radiation_at_earth.html
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http//www.windows.ucar.edu/tour/link/earth/clima
te/sun_radiation_at_earth.html
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http//www.windows.ucar.edu/tour/link/earth/clima
te/sun_radiation_at_earth.html
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Rays slide for sun path
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Roland Longbow wikipedia freeware
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Earth in the BalanceImpact of Sun on Temperature
400 300 200 100 0
Global Radiation (W/m2)
GEBCO
Temperature in the Beaufort Sea
The annual cycle of global radiation (brown line)
and surface air temperature (blue line) at a grid
cell location in the central Beaufort Sea. Values
were drawn from the Arctic Meteorology and
Climate Atlas gridded fields for global radiation
and two-meter air temperature. http//nsidc.org/ar
cticmet/factors/
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Earth in the BalanceCryosphere/Sea Ice
2003
1979
Sea ice extent in the Arctic has a huge impact on
albedo - reflectivity of Earths Surface
2010-2030
2040-2060
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UAF ACIA
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UAF ACIA
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Earth in the Balance
The snow and ice that cover the Arctic reflect
about 90 of the sun's energy, so the Arctic is
constantly losing heat.
http//www.aquatic.uoguelph.ca/oceans/ArticOceanWe
b/Currents/frontpagecur.htm
However, the ocean currents also exchange heat
currents from the Atlantic bring warm water into
the Arctic, while currents traveling southwards
discharge cold water.
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Earth in the BalanceImpact of the Sun on Oceans
and Ocean Circulation
www.ssec.wisc.edu/data/sst.html
Low latitude oceans are warm and move heat to the
poles
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Earth in the Balance
James Maslanik / University of Colorado
What makes this a habitable planet? What results
from the contrast between the tropics and the
poles?
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What controls changes in the oceans and the
atmosphere?
White water vapor Orange Precipitation
http//www.vets.ucar.edu/vg/CCM3T170/index.shtml
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Earth in the Balance Heat Distribution
68 100
Slide source Kevin Trenberth
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Earth in the BalanceHeat Transport
Two ways to move heat Ocean currents and
Atmospheric Circulation
Gulf Stream
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Low latitude oceans are warm and move heat to the
poles
The Gulf Stream
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Low latitude oceans are warm and move heat to the
poles
Leckie and Yuretich
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Seasonal Movement of the ITCZ
January (N. Hemisphere winter)
July (N. Hemisphere summer)
Source Pinet
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Earth in the Balance Thermohaline Circulation
The great ocean conveyer of heat and salts
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Earth in the Balance Thermohaline Circulation

• Warm waters move northward by winds,
• lose heat to the atmosphere by evaporation,
• become saltier, cool and
• sink to the deep ocean

WHOI
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Earth in the Balance Thermohaline Circulation
WHOI
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Arctic inflow
Arctic outflow
The North Atlantic Current provides about 60 of
the inflow to the Arctic Ocean bringing warmer
water from the Atlantic Ocean. Some water also
moves into the Arctic Ocean from the Bering Sea
and the Pacific Ocean, by way of the Bering
Strait.
Water flows from the Arctic Ocean into the
Pacific and Atlantic Oceans, as well as into a
number of surrounding seas. By far, the greatest
volume of water leaves the Arctic Ocean through
the passage between Greenland and Spitsbergen.
http//www.aquatic.uoguelph.ca/oceans/ArticOceanWe
b/Currents
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The Changing PolesClimate Change in the Media
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The Changing Poles Timeless Arctic Marine
Transport
ACIA
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The Changing Poles Arctic Marine Transport
INSROP (1999)
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The Changing Poles Arctic Marine Transport

• Reduced sea ice is very likely to increase marine
  transport and access to resources.
• ButWow!
• In 2007, we reached what was predicted for 2070
  only a few years ago!

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The Changing Arctic Greenland

• Increase in snowfall
• Increase in melt at edges
• Melt exceeds snowfall
• Yearly Melt Enough liquid water to fill a 51
  km3 lake
• 30 miles x 30 miles x 70 deep
• or
• add .005 to the world ocean

• Laser altimeter measurements from aircraft
• GPS Tracking of ice movement

Steffen et al., 2004 GRL
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The Changing Arctic Alaska
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The Changing Antarctic

• Ice Shelves
• floating
• melting does not raise sea level
• buttress ice sheets covering Antarctica (hold
  the ice back)

Wilkins Ice Shelf
Wilkins Ice Shelf begins break up in March,
2008--will it continue next year?
http//nsidc.org/news/press/20080325_Wilkins.html
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The Changing Antarctic
Larsen B Ice Shelf Collapse (2002)
National Geographic Society map
Approximately equal to the size of Rhode Island
http//nsidc.org/iceshelves/larsenb2002/index.html
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Seasonal changes cause zigzags in CO2 in the
atmosphere. Driven by Northern Hemisphere in
Spring - photosynthesis drops CO2, in Fall -
decomposition causes increase in CO2
http//scrippsco2.ucsd.edu/home/index.php
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Carbon Dioxide The last 300 years
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There is no analog for the future we face we
need no regrets strategies to reduce
vulnerability(NAS, 2002)
Carbon Dioxide The last 400 thousand years
IPCC Projections 2100 AD CO2 (450-1100) CH4
(1500-3700)
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Petit et al. (1999) Nature 399429-436
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Climate Change and CO2
From NOAA

• For hundreds of thousands of years, the Earth has
  imported heat in the tropics and exported heat
  via the poles maintaining a balance.
• We are certain that as CO2 goes up and down, the
  temperature of the earth follows.
• The loss of reflective surfaces in the Arctic
  with increasing global temperatures leads to
  positive feedbacks that warm the earth even more.
• CO2 is rising fast because of us Mother Earth is
  responding.

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NO REGRETS STRATEGIES (National Research
Council Report, 2002)
to reduce vulnerability and increase adaptation
at little or no cost, by nudging research and
policy in directions that will increase the
adaptability of systems

• Energy Policies - to slow climate change
• Ecological Policies -- land use coastal
  planning
• Forecasting of weather and weather related events
• Institutions -- water systems, insurance, and
  statistical data for policy reform

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Geological Past and Study of Depositional and
Biological Systems of Environmental Change