Jump to content
Snow?
Local
Radar
Cold?
IGNORED

Antarctic Ice Discussion


pottyprof

Recommended Posts

Posted
  • Location: St rads Dover
  • Weather Preferences: Snow, T Storms.
  • Location: St rads Dover
12 minutes ago, Methuselah said:

So it's 'situation normal', then? 😁

Nope read away from these first couple of pages, and you'll see there is significant ice melt on glaciers in Antarctica, and when sea ice is low, that increases, less protection from the seas.

  • Thanks 1
Link to comment
Share on other sites

Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.
Just now, alexisj9 said:

Nope read away from these first couple of pages, and you'll see there is significant ice melt on glaciers in Antarctica, and when sea ice is low, that increases, less protection from the seas.

You got me wrong, alexis. I mean situation normal, as in some folks not getting it! 😁

  • Thanks 1
Link to comment
Share on other sites

Posted
  • Location: West Yorkshire
  • Location: West Yorkshire

In relation to the discussion on historic sea ice - the paper is available here: https://ntrs.nasa.gov/api/citations/20140017193/downloads/20140017193.pdf

And on page 5:

Quote

The fact that our August 1966 is such an outlier indicates potential issues in the Nimbus August data. In addition, the drop in extent from July to August is not seen in the passive microwave record and is not physically likely. This issue may be related to the data quality, the effect of the timing of the imagery on the monthly composite estimate, limitations in the manual analysis, or other factors. AVCS data is not available for September, the month when the Antarctic typically reaches its maximum. On the other hand, in the 1972 analysis of the 1966 Nimbus II data, Sissala [14] reported an even lower August ice extent of 15.17 million km.

One potential explanation comes from the intra-month variability of the ice cover during August. Notice in Fig. 7 that there is significant variation in passive microwave ice extent in August, much more than in September. This is because the ice extent is still increasing in August as freezing occurs. So temporal sampling gaps or biases (i.e., sampling more early in the month vs. late in the month) can potentially bias a monthly composite estimate. Near the time of maximum extent in September both freezing and melting are occurring so there is less large-scale daily change and the potential for a sampling bias will be smaller. Qualitatively, we do see the high daily variability the Nimbus II data for August 1966. There is not signicant variability in the Nimbus I 1964 data in September, due in part, to the shorter 3-week record.

Though interesting, this is not  'slam dunk' proof that sea ice was lower in the 1960s than it is today. The current scientific consensus looks something like this:

  • Current sea ice levels show the greatest negative anomalies seen in the reliable satellite record (since 1979)
  • There may have been similarly large swings to today in the 1960s, but we can't really be sure because the data quality is very poor
  • More data is needed to attribute cause

The important thing is to go back to the original source, and understand any caveats and limitations.

In short, scientists are concerned about today's record low because it may indicate the beginnings of the trends we see in the Arctic emerging in the Antarctic. Despite the global warming signal, Antarctic sea ice has remained relatively stable until recently, so scientists are rightly concerned (IMO) about what this means for the future. It may be that this is just a natural cycle, and that at least for now, Antarctic sea ice will remain in a stable regime. But we can't really be sure either way.

Of course, whether or not this latest record low is attributable to climate change or not (which we may only be able to tell in retrospect), it doesn't change the broader picture of a global warming trend, which is attributable to the enhanced greenhouse effect.

  • Like 6
Link to comment
Share on other sites

Posted
  • Location: Crymych, Pembrokeshire. 150m asl
  • Weather Preferences: Extremes of all kinds...
  • Location: Crymych, Pembrokeshire. 150m asl

Another report….

WWW.THEWEATHERNETWORK.COM

Experts speculate that the Antarctic sea ice system has entered a new regime of much lower ice extent.

I always believed, as Alexis says above, that melting sea ice has no effect on sea levels but does allow faster glacial ice degradation and that accelerating glacial meltwater would increase sea levels globally.  In addition, I also understand that the reduction in sea ice affects the ice-albedo effect and promotes an increase in sea water temperatures, thereby accelerating the melting trend.  If the Earth has previously enjoyed a lengthy status-quo regarding sea ice levels it does appear that the balance is now tipping in favour of a gradual reduction of seasonal maximum sea ice in the Antarctic.

  • Like 2
Link to comment
Share on other sites

  • 1 month later...
Posted
  • Location: Yorkshire Wolds
  • Weather Preferences: Hot sun, storms & ‘Oh no can’t go into work - snowed in’ days
  • Location: Yorkshire Wolds
13 hours ago, Northwest NI said:

Great post!

what took you there. Work or some kind of expedition?

Expedition trip - of a lifetime! Always wanted to go but never thought possible then opportunity arose. Enjoyed all the landscape, wildlife & science bits on board 🤓. Weirdly I’m disappointed that we had the best run of weather, almost unheard of….a run of days of sunshine and little wind. Feel a bit cheated I’ve not experienced the ‘real’ Antarctic 😂…but made for a spectacular trip.

  • Like 6
  • Thanks 1
Link to comment
Share on other sites

  • 3 months later...
Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

The last two years have seen a very dramatic reduction in Antarctic sea ice:

 

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: on a canal , probably near Northampton...
  • Weather Preferences: extremes n snow
  • Location: on a canal , probably near Northampton...

More bad news....

 

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...