GB54;842843424 said:
I'm not sure the issue is framed correctly. Global warming is going to make us all extinct doesn't work because people know it's probably not true and it probably won't happen to them. Otoh if you're in Florida and the sea is rising you can see that; or if you're in Alaska or Montana and the permafrost and glaciers are melting. Energy cost reduction and renewables are also good sells. People don't give a damn about global warming but they do care about their local environment. The environmental movement has become just another D.C. lobby and phrases too many things in ways that have no relevance- has there ever been a sillier word than "sustainable. If you reduce electricity and transportation inputs, you are a large way to reducing carbon emissions but people think driving their car to the farmer's market to buy five "sustainable" tomatoes is good.
You can't really see sea rising in Florida. The rate of ocean rise has been steady at 6" per century, over the last couple of centuries. Contrary to popular belief, the rate of increase in sea level has not gone up dramatically in recent times, the yearly rise is still measured in millimeters. Here is the measured rise over the last century and a half in NYC:
About 2/3 of this rise in NYC is due to the city itself sinking at a rate of 2.12 mms/year (satellite measurements). Since the local tide gauge is recording a sea level rise of 2.85 mms/year, the real sea level rise is only 0.83 mm/year.
Broader historic picture of sea levels, on a larger scale it was mostly about the last ice age warming up:
A lot of the issues with sea rise boil down to local geology rather than a global rise in ocean levels due to melting arctic regions. Plates shifting, or land settling due to buildings (in Venice for instance), or groundwater depletion.
During the last drought in CA, land settled as much as half a meter in parts of the SJ Valley. That shift is the equivalent of several centuries' worth of ocean water rise at the current rate, this kind of puts the global ocean level rise in perspective.
Ocean shores are geologically dynamic environments, beaches shift, erode. So when someone is "noticing" sea rise, it's due to those kinds of local geological shifts.
There is no permafrost in Montana, and in North America, temperatures were significantly higher in the last warm period of the 1930s. Most of the polar ice is in the Antarctic, about 8-9 times as much as in the arctic (where the relatively thin polar ice cap floats, thus not affecting ocean levels), and
in the Antarctic, the ice pack mass has been growing (link).
