In Esa’s Cryosat mission sees Antarctic ice losses double, the BBC report claims that West Antarctic ice loss amounts to .43mm of sea level rise per year… 4.3 cm per century. This feeds a current narrative of the collapse of Antarctic glaciers.
But is it a collapse?
The volume of the Antarctic ice sheet is 25.4 million km³ and 10% of this is in West Antarctica. The ice locked into Antarctica is the equivalent of a 58m rise in the sea level – in total. So on a pro rata basis, West Antarctica is worth a 5.8 meter rise.
On these figures, the West Antarctic ice sheet would take 13500 years to melt. This collapse is a slow one. So how trustworthy are these figures?
Another study noted in Consider Clashing Scientific and Societal Meanings of ‘Collapse’ When Reading Antarctic Ice News shows a level of sea rise of about 10cm (4 inches) per century – but it may take several centuries to get to that level; well within the time frame of other larger climactic changes e.g. the Mini Ice-Age of 1250 to 1850. This is quite different to the figure in the BBC article. At 10cm per century, the West Antarctic ice sheet would finally vanish in 5,800 years. As far as the East Antarctic ice sheet is concerned, scientists seem satisfied that these aren’t for melting any time soon. Funny things, figures.
Talking about ice ages, the disturbing thing to me is that the recent Mini Ice-Age dovetails so closely into the present day that I wonder how it’s possible to construct a reliable control period of ‘climate-equilibrium’.
To put this into some kind of context, sea levels at the end of the last ice age rose some 120 meters in 10,000 years. that’s 1.2 meters per century. At the height of that thaw, seas rose 100 meters in 6 000 years. During that period the pulses (i.e. acceleration due to de-glaciation events) meant that it rose as much as 2.5 metres in a century. An event was when a pent up inland sea, such as Lake Bonneville, was released.