Moreover, if we end up with complete deglaciation of the ice sheets, the CA central coast would turn into a big peninsula all the way down to Paso Robles as the central valley becomes a huge bay.
Yeah. I'd look at how fast the ice has to melt in order for that to happen. Perhaps 21000 might be more likely. Spoiler alert : 2100 is just 85 1/2 years away. At the current rates, the ocean will have risen...gasp....10 inches.
Current consensus estimates put the expected rise at 2100 to be more like ~1 meter (http://www.theguardian.com/environment/climate-consensus-97-...). That's enough to, for example, permanently flood 1/3 of the roads of the Gulf Coast, erase several island nations and 1/3 the world's airports from the face of the earth, and render large parts of New York and Miami unlivable due to storm surge. Gasp indeed.
I doubt your estimates of the impact. For example, of the 124 airports in Florida, only 2 are below 1 meter elevation (St George Island and Key West International), only 16 are below 3 meters. So I doubt 1/3 of the worlds airports would flood, or for that matter 1/3 of the roads in the Gulf Coast.
Sorry, you are partially correct. I looked up the airport stat and it's specific to the Caribbean, not worldwide. Regarding the other claim however:
“It is estimated that a hypothetical 1 m rise in relative sea level projected for the Gulf Coast region between Alabama and Houston over the next 50-100 years would permanently flood a third of the region’s roads as well as putting more than 70% of the region’s ports at risk,” the IPCC said.
Note that ocean rise in tropical / subtropical regions is also exacerbated by thermal expansion of water. How much this contributes I'm not entirely sure.
Florida in particular also has a little issue you may have heard of with sinkholes. The geology is generally limestone, and this can be undercut by water and other effects. There's also the matter of saltwater intrusion on freshwater supplies and flora, as well as other secondary effects of seawater rise.
Manhattan island will inevitably be protected by Dutch-style hydro infrastructure. What the construction thereof will do to my tax rate is another matter entirely.
By 2070, 56 million people in Kolkata, Mumbai, Dhaka, Guangzhou and Ho Chi Minh City will be exposed to flooding. 10 million people will be exposed in Miami, New York, New Orleans and Virginia Beach. [0][1]
http://www.globalwarmingart.com/wiki/Special:SeaLevel