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Sea Ice & CO2 Levels

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  The Importance of Sea Ice

 
 

This simulation shows how increasing CO2 levels may affect sea ice thickness at the poles. Visualizations are shown for both a control run, where CO2 levels remain constant, and an experimental run, with CO2 levels increasing at 1 percent per year. The 50-year control run reveals no perceptible change in ice thickness. However, after 140 years of integration the increasing CO2 run obtains a quadrupling of atmospheric CO2 and shows a dramatic reduction in sea ice thickness at the North Pole. The ice thickness is depicted with a blue to white color mapping, where white represents the thickest ice.

     
     
Control Run, Monthly, Jan 170 - Jan 220
     

North Pole - Arctic

 

South Pole - Antarctic

     

QuickTime | MPEG

YouTube

Simulated Arctic sea ice thickness from the CCSM2 control run assumes present day atmospheric greenhouse gas levels and shows monthly variations due to natural variability of the climate. A large annual cycle is clearly apparent, and year-to-year variations in the ice cover are also seen. This is consistent with observations.
 

QuickTime | MPEG

Animations of monthly averaged data for the southern hemisphere also clearly show a large annual cycle.
     

Control Run, Jul-Aug-Sep Averages, Year 170 - Year 219

     

North Pole

 

South Pole

     

QuickTime | MPEG

By averaging over the Northern Hemisphere Summer months (July-August-September), the seasonal influences are dimished, making the interannual changes more evident. This control run animation reveals interannual variability (consistent with observations), but there is no perceptible change in ice thickness over the 50 year period.
 

QuickTime | MPEG

 

     

CO2 Run, Monthly, Feb 220 - Dec 369
     

In the CO2 runs, year 220 is present day and atmospheric CO2 is assumed to increase at 1% per year.

After 70 years of integration, CO2 levels have doubled from their present day levels, and there are large open water areas present within the Arctic basin during the late summer (September). By this time, the annually averaged global surface air temperature has warmed by a little over 1C. However, the warming in the Arctic is greater than 3 times this amount, and is the largest on the globe.

After 140 years of integration, CO2 levels have quadrupled from their present day levels, and the Arctic is largely ice free in the summer months. This has important implications for climate as well as effects on socio-economic conditions. Some nations, for example, are very interested in the possibility of opening shipping channels across the Arctic and exploiting this connection between the Atlantic and Pacific Oceans. Also, the disappearance of the ice pack could have a negative impact on wildlife such as seals and polar bears which use the ice pack for breeding and hunting grounds.

     

North Pole

 

South Pole

     


Sept 220


Sept 369

QuickTime | MPEG
(click images to enlarge)

A further animation shows the monthly averaged sea ice under a transient climate change scenario in which atmospheric CO2 increases at 1% per year. The large annual cycle is still observed, but the ice cover also steadily thins over the simulation.
 


Sept 220


Sept 369

QuickTime | MPEG
(click images to enlarge)

In the Southern Hemisphere, the sea ice does thin under the climate change scenario runs, but the changes are typically smaller than those observed in the northern hemisphere. This is likely due to changes in ocean heat uptake.
     
CO2 Run, Jul-Aug-Sep Averages, Year 220 - Year 369
     
North Pole   South Pole
     


Year 220


Year 369

QuickTime | MPEG
(click images to enlarge)

These visualizations show the JAS averages and include a red line that depicts the maximum extent of 1 cm thick sea ice from the summer averaged control run. Interannual variability is evident again, but there is a very perceptible change in ice thickness over the 150 year period.
 


Year 220


Year 369

QuickTime | MPEG
(click images to enlarge)

 

     
   
Model  
Model Name:
CCSM2
Data  
Data Size: A single monthly history file of ice model output is ~ 35MB. The ice concentration shown in the animation is only one field out of 57 data fields and 15 grid information fields on this file (all of which are on the same grid).
Data resolution: ice and ocean model grids at 320x384
atmosphere and land model grids at T42 (~ 2.875°)
CPU: NCAR's Blackforest (104-processor IBM SP)
CPU Hours:
700 CPU hours/model year
Wall clock hours: ~ 4 model years per wall clock day
Coverage  
Time Evolution:
50 year control run, 150 year CO2 run
Time Resolution:
Monthly and Jul-Aug-Sep Averages
Real World Dimensions:
Global
Project  
Scientific Credits:
  • Marika Holland, CGD/NCAR
  • Cecilia Bitz, U. Washington
  • Bruce Briegleb, CGD/NCAR
  • Elizabeth Hunke, LANL
  • Bill Lipscomb, LANL
  • Richard Moritz, U. Washington
  • Julie Schramm, CGD/NCAR
Visualization Credits
  • Fred Clare, NCAR/CISL
  • John Clyne, NCAR/CISL
  • Tim Scheitlin, NCAR/CISL
Date Created:

2003-02-01

Date Catalogued:
2003-03-05
Rights:
© 2002, UCAR, All rights reserved.