Showing posts with label open water. Show all posts
Showing posts with label open water. Show all posts

Thursday, September 19, 2013

Is the North Pole now ice-free?

Is the North Pole now ice-free? It could well be that, by the time you read this, there will be no ice left at all at the North Pole. The image below, created by Sam Carana from a nowcast from the Naval Research Laboratory, run on September 17, 2013 and valid for September 18, 2013, shows open water extending all the way to a spot very close to the North Pole.

As the color indicates, sea ice thickness in this area is virtually zero (i.e. ice-free). This development of an ice-free area at the North Pole has been discussed in earlier posts such as:
  • Arctic sea ice thickness falls by 2m in 21 days in some areas (June 13, 2013)
  • Open Water In Areas Around North Pole (June 22, 2013), describing areas around the North Pole where sea ice thickness had fallen to virtually zero, i.e. open water. 
  • Open Water at North Pole (July 22, 2013), descibing a wide corridor that had developed with very thin ice between the North Pole and Siberia. The post added that surface water on top of this thin ice could extend along this corridor, all the way from the North Pole to edge of the ice, in which case the surface water effectively becomes part of open water.
  • North Hole (September 2, 2013), describing areas close to the North Pole where ice volume had fallen to virtually zero, while pointing at how devastating the impact of sea surface temperature anomalies can be. 
This sea ice thinning in areas close to the North Pole has been one of the most important developments in 2013. Yet, many people keep watching sea ice extent.

Why was Arctic sea ice not smaller in extent in 2013 than in 2012?

The comparison below shows both volume and the extent of the sea ice for the same day in 2013 (left), respectively 2012 (right). Natural variability can make Arctic sea ice slightly smaller or larger than projected. There are many factors that influence things from year to year, such as weather conditions, sea currents and temperatures of the water in the Atlantic and Pacific Oceans; some factors are discussed in more detail below.

The above comparison shows a lot more ice north of Alaska in 2013 (above left) than in 2012 (above right). The comparison below shows that salinity levels in the Beaufort Sea were lower in 2013 (below left) than in 2012 (below right).

Seawater typically has a salinity level of over 3%; it freezes at about −2°C (28°F). Where mixing occurs with fresh water runoff from melting glaciers and permafrost, the water in the Arctic Ocean can become substantially less saline. Other substances added to the water, such as sand, can also cause a freezing point drop. The freezing and melting point of fresh water (i.e. zero salinity) is 0°C (or 32°F).  Less salinity means the water will remain frozen until the temperature reaches levels closer to 0°C.

Thinning continues

Heatwave conditions in Alaska caused greater melting of the permafrost. The result was more fresh water run-off through the MacKenzie River into the Beaufort Sea. This has contributed to keep sea ice extent larger in 2013. Yet, the warm water has also contributed to further thinning of the ice, reinforcing warnings that the sea ice looks set to disappear altogether within years. 

As illustrated by the above image by Neven, from the Arctic Sea Ice blog, average Arctic sea ice thickness (crudely calculated by dividing PIOMAS (PI) volume numbers with Cryosphere Today (CT) sea ice area numbers) has been very low in 2013.

The image below shows that annual minimum volumes appear to follow an exponential trend downward to zero, firstly reached in September 2015, followed by zero ice in the surrounding months over subsequent years.

Some people have objected against using PIOMAS data for such projections, with arguments ranging from suggestions that PIOMAS data were not reliable, that natural variability could prove such projections to be wrong, to questioning whether an exponential trend was appropriate. Nonetheless, it seems that over the years arguments in favor of an exponential trend have only become stronger:
  • Further measurements such as by CryoSat have confirmed that the PIOMAS data are indeed reliable and that the sea ice decline may well be even more dramatic. 
  • Natural variability goes both ways, it can either speed up or slow down ice melt. Had there been less runoff from the MacKenzie River, the sea ice in 2013 may not have been able to refreeze after being hit by cyclones several times. Next year we may not be so lucky and sea ice could disappear altogether, due to natural variability.  
  • Thick ice along the northern coast of Greenland is indeeed more persistent because of on-shore winds that cause the ice to drift and pile-up there. This would favor a Gompertz (or Sigmoid) trend in extrapolations (see image on the right). However, the new development of an ice-free North Pole shows that the sea ice is capable of breaking up abruptly, not only from the outer edges toward Greenland, but also starting at the North Pole and even moving from there toward Greenland. Moreover, as the 30-day animation below shows, thick sea ice north of Greenland can thin very quickly, suggesting it could well disappear altogether within one season.  

Sea ice can thin rapidly, even when it is multiple meters thick 

Earlier in 2013, much warm water entered the Arctic Ocean from the mouths of rivers, as discussed in the post Arctic Ocean is turning red. As said, this resulted in lower salinity levels in the Beaufort Sea that prevented cyclones from demolishing the sea ice altogether. Nonetheless, the joint impact of cyclones and warm water does appear to have caused rapid decline of the thick ice north of Greenland and Canada, as earlier discussed in an earlier post

Furthermore, sea surface temperatures have been recorded close to Svalbard that are far higher than even in the waters closer to the Atlantic Ocean. This phenomenon is illustrated by the image below, showing sea surface temperatures (top) and sea surface temperature anomalies (underneath). 

In some of these spots, sea surface temperatures are well over 10°C (50°F). Where does this heat come from? 

These hot spots could be caused by undersea volcanic activity; this is the more dangerous as the area has seen methane bubbling up from hydrates that have become destabilized; such dangers have been discussed repeatedly, e.g. in the post Runaway Global Warming. Hot spots can also contribute to even more dramatic thinning of the sea ice, including the thickest parts. 

In conclusion, there is no reason to assume that the sea ice in the Arctic will somehow magically recover. Instead, there are many indications that exponential decline of Arctic sea ice will continue. Less salinity may have temporarily prolonged the extent of the sea ice in some areas, but as sea surface temperatures keep rising, the ever thinner ice looks set to collapse within years, with dire consequences. This calls for comprehensive and effective action, such as described at the ClimatePlan blog.  

Related posts

- Arctic sea ice thickness falls by 2m in 21 days in some areas

- Open Water In Areas Around North Pole

- Open Water at North Pole

- North Hole

- CryoSat - New Dimensions on Ice

- Arctic Ocean is turning red

- Cyclone raging on thin ice

- Runaway Global Warming

- Climate Plan

Monday, July 22, 2013

Open Water at North Pole

Images from the North Pole Environmental Observatory are now showing large areas with open water at the North Pole. The image below is from Webcam 2, dated July 22, 2013.

[ click on image to enlarge ]
Furthermore, the number of spots with methane readings of over 1950 ppb appears to be rising. See related posts below to compare. Particularly worrying are the large number of spots over the Kara Sea. Also note the spot over Greenland in the top-left corner of the image below.

[ click on image to enlarge ]
The webcam shows water at the North Pole. Clearly, there still is some ice underneath the water, as is evident from the stakes that have been put into the ice to indicate the depth of surface water.

Surface water can build up as a result of melting as well as due to rain.

As the image on the right shows, the ice is getting very thin. In between the North Pole and Siberia, a wide corridor has developed where the ice is between zero and one meters thick.

Surface water could extend over this corridor, all the way to edge of the ice, in which case it effectively becomes part of open water.

The presence of water in areas close to the North Pole has been discussed in a number of earlier posts, such as this one.

The image below, from the Danish Meteorological Institute, gives some idea of the extent of the sea surface temperature anomalies that have been particularly prominent in the Kara Sea for some time.

Meanwhile, more water has appeared around Webcam2. Below are four later images, the top two images captured on July 24, 2013, the third one captured on July 25, 2013, while the bottom one was captured on July 26, 2013.

Note that the buoy associated with Webcam2, while originally positioned at the North Pole, has meanwhile moved away substantially from that location, as indicated by the image below, from

Ice thickness image run July 26, valid July 27, 2013
for scale, see image further above. Buoy data up to July 28, 2013, buoy position: 84.87 N, 4.29 W.

On the animation above right, the track is shown against a sea ice thickness map, showing sea ice at webcam2's current position that is two meters thick.

So, while satellite images may indicate that the sea ice is still several meters thick in many locations, huge amounts of surface water may be present on top. The albedo of water is far lower than ice, so less sunlight is reflected back into space and a lot more heat is absorbed by the water, further accelerating the sea ice melt. This spells bad news for the remaining sea ice, since the melting season still has quite a bit of time to go.

Let's end with a video uploaded at youtube by covering the period from April 16 to July 25, 2013.

Related posts

Open Water In Areas Around North Pole (posted June 22, 2013)
Watching methane over Arctic Ocean (posted July 20, 2013)
Heat, Fires and Methane (posted July 20, 2013)
High methane readings over Kara Sea (posted July 18, 2013)
Methanetracker (posted July 9, 2013)