World GDP is around 59 trillion dollars, says the CIA.
So how close to 59 trillion dollars worth of stuff is:
near enough to the coastlines to be flooded by rising sea levels
wrapped up in agriculture that could be affected by severe drought
on land that could subside due to coastal erosion
near enough to the oceans to be affected by a putative increase in cyclonic activity
etc.
?
Well, here’s some numbers for only Japan, and for only the “rising sea levels” problem.
109 trillion yen is (at today’s rates) about one trillion US dollars. But that’s just for Japan. If we scale it up to include all of the earth’s coastlines, and then try to account for all the other things besides rising sea levels, could we increase that by the factor of 60 needed to get to current world GDP?
Bear in mind that it would only have to happen once to diminish annual global GDP to a fraction of what it was before.
In the US, Katrina, damaging a small area of coastline that included one major city and a bunch of towns, did an estimated $100 billion damage. Scale that up to include flooding in all US coastlines and every single major city thereon, including the much more wealthy and fiscally valuable Houston, NYC, DC, Philly, Boston, Miami, Seattle, etc., then throw in all the oilfields. And the minor conurbations nearby (have you seen the real estate prices in Connecticut?). Add in Québec and Vancouver.
The UK and California are both just-about comparable, economically, to Japan - 3rd and 4th largest global economies, IIRC. Both have a majority of economic activity on or near to coastlines (London, LA, San Francisco, San Diego).
Then there’s the prospect of the Netherlands and Belgium completely disappearing, the loss of Marseilles, Nice, Cannes, Naples… And of course you can’t put a value on the loss of Venice.
And that’s just Europe and North America. It’s not inconceivable.
