The atmospheric concentration of CO2 today is 30% higher than when recording began in 1958, and the rate of the increase is faster now than in the last decade. The last time CO2 levels were this high was during the Pliocene 3-5 million years ago, when temperatures were around what they are now, (they may have been lower than today) and the world’s oceans were about 20m higher than they are now.
The ~20m increase in sea level will come from the West Antarctic Ice Sheet, Greenland and East Antarctic. A goodly proportion of that has the potential to come up fast, and sometime this century, due to the twin effects of hydrofracturing (when surface melt creates crevasses that reach down to bedrock – eg, Greenland) and ice cliff failure (a loss of structural integrity when ice cliffs are no longer buttressed by sea ice and the like – eg, Antarctica).
Ice melt from WAIS, East Antarctica and Greenland barely rate a mention in IPCC assessment reports and therefor do not factor in government responses to AGW.
Which might explain why we get the likes of Green Party co-leader James Shaw believing that –
New Zealand can lead the world in transitioning to a high-value, clean-tech, post-carbon economy that works for everyone.
Yeah – with just over 1m of sea level rise, we lose huge swathes of agricultural capacity due to all the world’s deltas being inundated and salinated – a loss of some 25% of the world’s crops according to Professor Peter Ward. [33:00] (The average ratio of sea level rise to horizontal migration of salt is 1:100 – ie, 1m of sea level rise is accompanied by a 100m band of coastal land/groundwater being salted). And then there is all that infrastructure sitting at or below sea level – roads, rail networks and, soon, (somewhat incidentally) a hospital in Dunedin.
Now call me dull or unimaginative, but I’m just not seeing the business opportunity in that.
And a projected 1m by 2100 is likely to be off the policy makers’ and politicians’ table pretty soon.
As I wrote recently, if we took all of the buildings we currently have – all of the towns and cities in all of the world – and placed them on the rock beneath the ice that is going to be adding to sea levels – then everything we have built everywhere would disappear under the ice; nothing would be poking out. And still we wouldn’t have covered all of the rock that’s sitting beneath the ice that’s coming our way.
We have only one opportunity to stop what we are doing. Or maybe it’s the case that we only had one opportunity.