Anthony Watts explains that it is. The sea would have to rise around 65 metres to reach that level, and rising at the same, constant rate it has risen for the last 150 years, 2.77+/-0.009mm/yr, it would take 23,537 years; but the water level rise is unlikely to last so long: an ice-age is likely to supervene. He does not like the expressions “denialist” or “denier”: that page also distances him those he says deny the greenhouse effect itself.
No doubt elsewhere he has dealt with tundra methane and the ice caps, but this post by itself is not enough to refute the picture. I found the BBC announcing that if the Antarctic ice sheet were to melt, mean sea level would rise by 58m, enough to wet Liberty’s skirts. It is 26.5m cubic kilometres, or 26.5×10^18 litres.
The BBC also deals elsewhere with global warming, and does not say such melting is likely. I went googling. A calorie of energy, or 4.18 joules, raises one gram of water by 1°C. 4180 joules raises a litre of water by 1°. It would take a lot of energy to melt the Antarctic.
The question is, how much additional energy is retained in the system because of greenhouse gases. Once I read of the Stefan-Boltzmann response and feedback loops and the
understanding that in one billion years’ time the Sun will be 10% brighter, producing a runaway greenhouse effect and extinguishing life on Earth, I am well beyond claims I can assess myself.
I read that “The rate of ice loss from Greenland has increased almost five-fold since the mid-1990s”. That article does not tell us the rate of ice loss. This article does not appear to come from “deniers”, and says the current melt of Greenland ice contributes one hundredth of an inch to sea-level rise per year.
It also discusses melting of polar ice. A million square miles of perennial sea-ice has disappeared in thirty years. That does not in itself raise sea-levels- ice displaces the amount of liquid water it would become if it melted- but that ice is no longer reflecting solar energy into space: instead it is liquid water, absorbing much more of the solar energy.
Liberty paddling is a viscerally scary image. Does NatGeog give detail to justify scaring us like that? With seas four feet higher than they are today—a distinct possibility by 2100—about two-thirds of southeastern Florida is inundated. The Florida Keys have almost vanished. Miami is an island. A four foot rise is much less than a 65m rise, but it would change the lives of coastal people in all continents sufficiently to give poetic licence to the picture of Liberty. Scaring people would be justified.
So the question is, is that a “distinct possibility”? If the rate of rise of sea level remains constant, as Anthony Watts implies, and North Carolina Republicans prohibit questioning, sea level rise will be eleven inches. Without a science degree, I believe the rate of rise will increase. How scared should I be? I haven’t a clue.