It was kind of Charlie Stross, a participant here on HN
http://news.ycombinator.com/threads?id=cstross
to take time out from writing his latest novel to post the interesting blog post shared here. Thanks too to the HN participants who shared the link and have commented already while I was coming back from work. I especially like about this post that Stross looked back at Earth 500 years ago to show readers what time scale he is talking about, and that he was boldly definite about technological and social changes.
I will be boldly definite in disagreeing in part with one of Stross's conclusions in this interesting post. Stross writes, "I'm going to assume that we are sufficiently short-sighted and stupid that we keep burning fossil fuels. We're going to add at least 1000 GT of fossil carbon to the atmosphere, and while I don't expect us to binge all the way through the remaining 4000 GT of accessible reserves, we may get through another 1000 GT." I fully agree with this premise. There are no effective incentives in place today, nor any likely in the next few decades, to prevent further consumption of fossil hydrocarbon fuels, and that will surely result in a substantial increase in atmospheric conentration in CO2.
Stross's next step in prediction is, "So the climate is going to be rather ... different." That's a safe prediction any time, because over 500 year time scales, we have often observed climate change in historic times. Over longer time scales, but since Homo sapiens populated much of the earth, rock art in the Sahara Desert shows that the Sahara was once much less arid than it is now, and cave art in Europe shows that the climate of Europe was once much more frigid than it is now.
Stross goes on to write, "Sea levels will have risen by at least one, and possibly more than ten metres worldwide."
An interesting series of online maps shows projections of flooded land based on various degrees of sea level rise for places of interest such as New York City,
http://geology.com/sea-level-rise/new-york.shtml
San Francisco,
http://geology.com/sea-level-rise/san-francisco.shtml
the Netherlands and England,
http://geology.com/sea-level-rise/netherlands.shtml
and Chesapeake Bay.
http://geology.com/sea-level-rise/washington.shtml
In all cases, the maps default to showing seven meters of sea level rise and do not project any civil engineering projects to protect existing infrastructure.
Having read Matt Ridley's blog post "Go Dutch"
http://www.rationaloptimist.com/blog/go-dutch.aspx
back when it was published, I wonder if the most dire predictions about the Netherlands are true, or if the Netherlands, the land of polders,
http://static.nai.nl/polders/e/index.html
can continue to be "living proof to climate pessimists that dwelling below sea level is no problem if you are prosperous."
Stross writes, "Large chunks of sub-Saharan Africa, China, India, Brazil, and the US midwest and south are going to be uninhabitably hot."
I live in the United States Midwest, and my mother grew up in a hotter part of the United States Midwest during the Dust Bowl era. Most of her family is still near the family farm on the windswept Great Plains. I don't expect any part of the earth to become uninhabitably hot. We have, according to the best developed models of influences on world climate, a sure prospect of a generally warmer Earth, warming currently lethally cold areas into areas that will be habitable. My experience living in subtropical east Asia suggests that we will have more warming of cold areas than turning hot areas into unbearably hot areas from global warming.
Stross continues, "London, New York, Amsterdam, Tokyo, Mumbai — they're all going to be submerged, or protected by heroic water defenses" and my prediction is that New York, at least, will be fully protected by civil engineering projects. New York City is sufficiently prosperous to attract some of the world's brightest minds to live there (I know some young people who have moved there recently) and the current city administration actively encourages making New York City a technology hub. New York will thrive, whatever the climate.
http://abcnews.go.com/blogs/technology/2012/11/new-york-can-...
Stross wraps up this prediction by mentioning, "Venice and New Orleans (both of which will be long-since lost)." Venice and New Orleans have been in long-term decline for quite a while, from bad governance, and will surely suffer further relative decline, regardless of sea levels. There will still be a great port at the mouth of the Mississippi-Missouri river system, and it will be a thriving and cosmopolitan city, but it may well be in a different place along the river delta from the current location of New Orleans. Venice may basically vanish.
There is much more interesting content in Stross's post, but allow me to explain why I think the high end of global warming predictions (and thus the high end of sea level rise predictions) is unlikely. We already have a known model for induced global cooling from the "natural experiment" of volcanos erupting and ejecting much dust high into the atmosphere. If the climate change we now experience produces more pain than gain (where I live, at 800 feet above sea level in a continental dry, cold winter climate zone, global warming has so far mostly produced gain), then there will be political and economic incentives to sequester greenhouse gases, or directly shade the Earth with high-altitude dust, or to do whatever else science discovers to slow and perhaps eventually reverse global warming. Over a 500-year time span, I would expect enough of an increase in understanding of climate models to bring about a world climate that is more moderate in more places than today's. Thanks for the chance to think about the far future.