Speaking for myself…when I try to think of Antarctica, then besides all those beautiful images I’ve seen, and besides having no real idea what minus a hell of a lot feels like, all I have is words like “vast” – or “forever”. And that’s about it. In other words, I can’t grasp it – I can’t comprehend the scale of the place.
So when I hear that the West Antarctic Ice Sheet is melting, all I can conjure up is images of what might constitute “melting” (pools of water, calving events)…and then blank.
The West Antarctic Ice Sheet covers an area of just under 2 million square kilometres? – blank.
The thickness of the ice covering Western Antarctic is up to 2000m or 2 km thick? – kinda blank.
When the West Antarctic Ice Sheet disintegrates it will raise sea levels by about 3m….now, that I can kind of envisage, at least in terms of my locality.
In an attempt to get some kind of conceptual grasp of what we’re referring to when we talk of Antarctica, I tried to think of something I might at least partially “get” that I could sit alongside it in terms of scale.
So I did a quick search to see what land area is covered by cities, thinking that might give me some vaguely graspable reference point. I mean, we’ve all seen the aerial views of New York, and many of us have traveled through endless kms of conurbation, right?
So anyway, the land area covered by all of the worlds urban development is about 3.5 million square km. That’s according to a study done by Columbia University that some are saying is a huge over-estimate in terms of area.
Regardless. If I take every single urban experience I’ve had, be it London, Paris, New York or Auckland, and I add beside that, Shanghai, Mumbai, Tokyo, Buenos Aires…then when I’ve finished tallying up all the endless horizons of concrete and steel, (images provided) I can fit the whole damned lot on to West Antarctic and Greenland (the other major source of sea level rise) and still have half a million square km of ice left over.
That’s ‘everything built’ by humanity fitting onto the surface area of ice that’s currently melting.
I can get that conceptually. Sort of. All of that ice melting is like all of our cities dissolving (or some such). Except, not quite. We need to do something with what this mega city comprised of concentrating all the world’s cities/built up areas into one place looks like.
The ice on Antarctica (Western) is up to 2km thick. (Greenland ice is between 2km and 3 km thick) The Twin Towers were just over 500m tall. So take every piece of built up area (the suburb you live in – Everything) and imagine there is nothing except Twin Tower after Twin Tower after Twin Tower – and then multiply the height x2…or x3 to get some rough approximation of the volume of ice we’re talking about.
Now compromise the foundations of all those exaggerated “Twin Towers”. They’ll stay standing…for now. But their collapse isn’t a matter of ‘if’, but ‘when’. That’s essentially the state of affairs for the Western Antarctic under current climatic conditions.
The IPCC and all government reports on sea level rise acknowledge that ice melt from Western Antarctica has not been taken into account when they say there might be a 1m rise in sea levels this century. That’s about 3m of additional sea level rise that’s been waved off to the side.
And here’s the fun bit.
Whereas it has been suggested that such a colossal amount of ice would take thousands of years to melt down (as though we were talking of some big ice cube just melting off into the ground), when researchers take processes like “ice cliff failure” (max possible height for an ice cliff being about 100m) and hydro-facturing – (think water and crevasses) – and factor them into modeling, then the collapse of the West Antarctica Ice Sheet occurs over decades, not centuries, and certainly not thousands of years.
And we know the fuse has been lit. Exactly like having compromised the foundations of the buildings in our imaginary city, the only thing we don’t know (and probably can’t ever know in advance) is when the collapse will begin
If you’re reading this and thinking that scientists have just modeled for a worst case scenario, and so have exaggerated some processes to get a nice OMG! result, you’d be wrong. What they have done is made the models emulate the known conditions from the last time the world’s atmosphere contained this much CO2 – three to five million years ago during the Pliocene when temperatures were around 2 – 3 degrees C warmer and sea levels about +25m higher.
By the way, there was no irony intended when I suggested looking at expected ice melt in terms of all of the worlds cities falling over. But it’s there, given that the foundation (however defined) for many of those cities will be knocked out by rising sea level.