NASA has excellent videos explaining Arctic sea ice


Less summer sea ice = less cooling albedo = more warming

Tipping Arctic sea ice 08 Lenton sea ice comparison nsi

NASA animation 1979-2011

sea ice extent



NASA animation 1979-2012

multi year ice


The Arctic acts as a thermostat for the global climate.

We can expect to see Arctic change have global environmental and socioeconomic consequences. ( Don Perovich, Dartmouth University expert on sea ice 2012)


The science is covered in some detail by earth. Arctic sea ice fluctuations pose significant impact on local climates.  Changes in sea ice cover alter surface heat and radiation fluxes, surface and atmospheric temperatures, precipitation characteristics, storm tracks, cyclonic activity, as well as local and synoptic scale atmospheric circulation. These modifications are known today to propagate to the lower latitudes with potentially significant consequences for global climates.


There are in fact several contributions to the sea ice melt positive feedback, that results in more warming,


  • Loss of snow and sea ice reflectivity of solar energy (ice albedo feedback)

           - both thinning and loss of extent reduces sea ice albedo.

  • Thin sea ice also lets more solar energy through the ice warming it from inside

  • Heat energy absorption by exposed dark open water and land surface

  • Loss if sea ice insulation of water.

  • Latent heat of ice


The feedback increases the Arctic regional warming, Northern hemisphere warming and lastly to some degree global warming.


The whole feedback process is also self accelerating, because more local Arctic warming directly melts more ice and snow.


Latent heat of ice

This is a big factor though it is still not taken on board by many environmental scientists. The point about summer conditions is that as long as there is SOME ice present on the sea surface, however thin the layer, then the ocean temperature below it is held to 0 degrees C because the absorbed solar radiation melts the bottom of the ice rather than warming the water. Also the atmospheric temperature is held to close to 0C because warmer air melts the surface snow layer on top of the ice and is thereby cooled. The sea ice, even when thinned, continues to act with 100% efficiency as an air conditioning system for ocean and atmosphere alike. BUT, as soon as the sea ice layer goes, this process ceases and the sea can warm up rapidly (to typically 7C by the end of summer - which is not much colder than the North Sea), as can the atmosphere (which speeds up Greenland ice sheet melt when that warmed air passes over Greenland). Latent heat is an enormously powerful buffer - the amount of heat that you have to pump in to melt 1Kg of ice will subsequently heat that same amount of melted water to 80C.


So once the ice goes away entirely there is a big jump in temperatures in the upper ocean and atmosphere (with dire consequences for permafrost), and it is very difficult to see how one can ever go back to an ice-covered summer ocean once this has happened. (Prof Peter Wadhams personal communication).


sea ice feedback eoearth feedback aa si sea ice alb photo melt ponds

         Important Research


14 Feb 2014 PNAS Arctic thaw significantly worsens global warming. Since 1970s +2C  48% albdeo loss = 25% of CO2 warming


 Feb 2013 Nature ..sea-ice extent on Arctic  greenhouse-gases

Frans-Jan W. Parmentier



Feb 2013 The past shows Arctic always 3X faster -amplification inevitable.        2 studies

Miller / Ballatyne


2009 PNAS Notz. The future of ice sheets and sea ice: Between reversible retreat & unstoppable loss 


2009 Could Arctic Sea Ice Retreat Drive Changes in Air Pollution Levels? &OH A. Voulgarakis

Arctic increase rad absorbed NASA