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Arctic Sea Ice Hits Record Low Extent
mdsolar writes "Arctic sea ice has hit a record low extent for the period of satellite observation. Further, this record has been set in August when the minimum annual sea ice extent (and the prior record) has always come in September. Further still, the ice is still retreating as rapidly as it was in June and July when normally the decrease of sea ice extent slows in August. It is thus possible the the final minimum sea ice extend for 2012 will be seen in October rather than September as has always occurred in the past. More than one monitoring effort agree on the existence of a new record."
If you read response #4 of this update from Real Climate, you will see that the National Snow and Ice Data Centre hasn't called the record low yet (as of 26 Aug 2012 at 12:04 PM), since they use 5-day moving averages on their graphs. The graph referred to by the realclimate.org update and I think in the OP is based on daily data. The response is from Walt Meier of the NSIDC. I'll quote it here:
These are daily values, not the 5-day average, which is not quite at a record yet. Using a 5-day average removes some of the noise due to weather and other effects that cause small errors in the daily values. Thus the 5-day estimate is a more robust measure of sea ice changes. We will make an announcement on our web site when we have passed the current record: http://nsidc.org/arcticseaicenews/
Walt Meier
NSIDC
I think however that there are other data series that do agree that the record has been broken, even with 5-day averages. Here is my favourite data compilation for Arctic Sea Ice. It contains many different graphs from different sources. Taken together, the data paints a disturbing picture.
This and no other is the root from which a tyrant springs; when first he appears as a protector - Plato (423 to 327 BC)
By October the air temp is around 13 degrees Fahrenheit. The max is 18 degrees and the minimum is 8 degrees. Days with Min Temp Below Freezing 31. http://www.climate-zone.com/climate/united-states/alaska/barrow/ Are you still gonna stand by your statement of melting in October??
Do you realize how much time and energy it takes to raise a mass of water even one degree? It's why water temperature is always behind air temperature. You can have 90 degree days all through June and still have cold water temperatures yet still be swimming in September when air temperatures are cold. Water is a wonderful heat sink.
Explorers have unsuccessfully sought a Northwest Passage for a lot longer than climate satellites have been orbiting the Earth, so it seems likely that the current minimum dates back to pre-industrial times, at least.
But if you're arguing that "we need more research", then by all means advocate for that to your congressional representatives. House Republicans have been trying to slash climate research funding for a long time. They're also trying to prohibit the National Institutes of Health from funding health economics studies. I wonder what issue that might relate to?
See no evil, hear no evil...
Actually the true statement IS that "this has never happened before". Ok, maybe it did happen in the interglacial periods before the last ice age, but not in the last 1450 years for which we have ice cores and other proxy data... and by that point there is no reason to not assume it to be true for the rest of our current interglacial unless you have some good argument to the contrary. You don't NEED the rather super-precise satellite observations we have for the last 33 years to make this kind of statement.
If this weren't so tragic it would be really funny seeing you deniers all flailing madly about for a way out of this one.
With regard to the Arctic melt of recent years, the VOLUME has been on a steady downward trend with little to no recovery. Extent is probably the easiest to measure but, by itself, it can be very misleading and is heavily influenced by waves and winds.
Pain is merely failure leaving the body
You are absolutely right. Volume and area are more telling than extent but as you say extent's the easiest to measure and volume the most difficult. With the launch of Cryosat in April 2010 volume measurements are much more accurate now. That page I cited has graphs for extent, area and volume.
Cryosat uses SIRAL (a synthetic aperture radar/inferometric radar altimeter) to measure the altitude of sea ice over sea level to get the volume. Since ice is about 9% less dense than water you can tell how much ice there is by how high it sticks out of the water. If a 5 cm layer is at the surface then Cryosat will show an elevation of a little less 0.5 cm. I don't think there is such a thing as submerged lumps of thick multiyear ice because something would have to be holding it down to keep it from floating at the surface. There may be some relatively small areas that are held under water by mechanical pressure but they still contribute to the overall ice elevation in the area.