NASA sea level briefing 2015/08/26

On Wednesday NASA had a briefing on sea level rise. I had no time to listen but this is the homepage for that briefing:
As Seas Rise, NASA Zeros In: How Much? How Fast? | NASA

. . . Residents of China's Yellow River delta are swamped by sea level rise of more than nine inches (25 centimeters) a year.
. . . ​

I know sea level rise is not uniform and even decreasing in areas of glacier rebound and faster where the land is subsiding but this is amazing.

Bob Wilson

 

Nothing much has changed in that respect:
http://tidesandcurrents.noaa.gov/sltrends/sltrends.html

I'm amused by the 10 year anniversary, Katrina stories that I have been switching off. In those 10 years, global sea level increased ~32 mm, 3.2 cm, ~1.25 inches. This is about the space between the mouth and nose. What I find more interesting is the effect on sea facing glaciers.

As the mean sea level rises, aside from undermining, the real issue is off-loading the weight and braking force at the bottom. Friction has a curious, non-linear behavior. The static coefficient is higher than the dynamic friction. Once motion starts, the drag force goes down, significantly. There is one mitigation.

There is an annual swing of ~10 mm during the year ending ~3.2 mm higher at the peak sea level of each year. The floating and near-floating ice sees a larger annual sweep than the annual increase. The annual, sea-level peak appears between July 1 and Sept 1 but Arctic melt and Antarctic freeze has another three weeks:

• Arctic sea ice melt had a surge this week
• Antarctic sea ice freeze flattened out this week

If we reach October 2015 without a major glacier event, then sea levels should follow the expected decline and the next risk will be five months later, March 2016, for the Antarctic melt season. Ice cracks both ways and Antarctica risks ice shelf break-ups.

One mitigation, we've seen northern Greenland have a lot of melt-days this year but the Summit station has not reported wide-spread, surface melt. The old Arctic sea ice still abutts the northern Greenland glaciers.

Bob Wilson

 

On a somewhat related idea:

A stadial freeze, predicted due to a collapse of the North Atlantic Thermohaline Current would follow in the wake of large-scale melting and discharge of large parts of the Greenland ice sheet. With further rise in atmospheric CO2 this would constitute a transient stage in global warming.

Source: How to make sense of 'alarming' sea level forecasts​

I have not studied the 'North Atlantic Thermohaline Current' but noticed from the Unisys sea surface temperature (SST) the summer cold spot southeast of Greenland which has been evident this 2015. Reports are the effect on the thermohaline current is from freshwater melt effect. Now I'm wondering if it is seasonal?

Another puzzle to noodle out of the Unisys SST data. I've been more interested in the Pacific Northeast-Central, warm water blob because of the effect on our west coast cousins.

Bob Wilson