But look at what the authors say, that we don't know the processes.  We don't even know all the measurements.  Anyone who thinks we really thinks they know what is going on is probably full of it.  I was just reading an academic article about the anthropogenic impacts on jellyfish today, and the authors had to conclude that we didn't have a clue.  So I think some of the piss & vinegar is a little bit misplaced.  

The key passage is "Nevertheless, alternatives to model-based approaches, such as empirical analysis and expert elicitation, were available for exploring uncertainty in 21st-century and long-term sea-level rise..."

Mathematically, that makes absolutely no sense.  I mean come on, man, I've got Monte Carlo, neural networks, and all kinds of stuff to measure uncertainty - but that only applies to today's measurements, not the models to project the future.  Bingo, hit the nail on the head.

Wow, scored some points but it's like predicting hurricanes - Mother Nature does what she does and damn all the nice stuff of mice and men.  /sam

Onward through the fog

Sea levels are rising, and will continue to rise even under the best circumstances.  The IPCC estimates give an additional 17 cm (max) due to scaled up discharge, which is woefully inadequate based on paleo data.  Expect at least 1 meter by the end of the century.

at the rate of 1 mm per year. expect that there is a very real possibility that all these horrendous sea rises you keep predicting might not happen.
what will you do? turn to god? become a republican? pack your bags and travel the (perfectly healthy) world? nobody knows...

Right on.  Until relatively recently in geologic time-frames, the sea had been dropping.  18,000 years ago in Texas the sea was over 600 feet higher; 5000 years ago is was maybe 20 feet higher than the current datum.  We're in a regime of sea level rise now, barely detectable if you control for astronomical and storm tides, but yes, since about 1944 we have excellent data to back that up.  Even a review of one tide station over its history, you can tell it is not a linear process - or natural log either.  The trend is definitely up.

The question about sea ice seems moot to me, since that ice is already floating in the water.  Effects of a melt in pack sea ice would therefore be minimal.  However, glacial ice, and continental shield ice, now that's a different story.  That's why scientists are very concerned about the Greenland and Antarctic glaciers - and less so about non-polar glaciers.

Onward through the fog

I suppose there's two ways to deal with the future:

You prepare for what very well could happen.

You go to the closet and hide under a bunch of coats.

Actual current sea level rise is about 3.3 mm per year.  Since temperatures are moving higher, you can expect faster sea level rise in the future due to the thermal expansion of the ocean and increased melting of glaciers and ice sheets.  Since it is intuitively obvious that ice does not melt linearly, you can expect some geometrically increased melting in the future.  Whatever the rate is, it is considerably higher than what any model has predicted, based on their failure to predict what we have already observed.