The Dense States of America (Map)
strangemaps.wordpress.com
strangemaps.wordpress.com
That being said, a more relevant question is what the societal effects would be. My first question is how this would affect crime rates. A quick search seems to indicate that crime rate may go up with population density, though other factors are, of course, more highly correlated (such as poverty).
Some of those other factors also correlate highly with high density areas. No clue what the causative links are ... could be that density has no effect, or even reduces crime rate, I suppose - I'm way to lazy to research it for ta quick hn comment!
I do know that being too close to too many other people makes me think about perpetrating violent crime, though! ;)
The problem comes for people like me: I enjoy my small city experience. I live a short walk from downtown, but have a house w/ yard (and a big garden), and a garage/workshop (mostly workshop as I don't actually have a car). Such space uses are unrealistic as density goes up.
A 1 megaton nuclear bomb detonated near the surface has a blast radius of about 1.7 miles. Pretty much nothing is left within this circle. Meaningful lethal damage only continues out to about 2.7 miles.
A 1.7 mile radius translates to roughly 9 mi^2. A 2.7 mile radius is roughly 23 mi^2. To carpet bomb New Hampshire, you'd need a lot of nukes. About 988 of them in fact.
Now 25 megatons is more interesting... you'd need about 68 of those to ensure <2% survival rate, or 25 of them if you are satisfied with <50% survival rate.
Of course, with good placement and strong winds, you could effectively kill 99% with only about 12-15 one megaton bombs. All that radioactive dust from the mushroom cloud comes down somewhere, and with a 15mph wind, that means a lethal dose within 90 miles of ground zero,
One nuclear launch can easily land well over a dozen nukes with considerable tonnage.
The real question is what's more cost effective 1000 1-megaton nukes or 70 25-megatons? 1000 megaton total vs 1750 megaton total.
This ignores that a larger area with similar population density would require much more robust transportation systems than currently exists in, oh, the world. Have a happy mental visualization:
Take every car in America on the road right now. Divide by, say, 100, assuming that most are driving ~ 1 hour, and the new density would make their trips within 6 minutes after such a change, and the transport system fits 10 people into the space of one car.
Now, cram them into New Hampshire. And imagine rush-hour traffic.
Second, it is using the current population density of Brooklyn, and that is with the current transportation infrastructure. If your foreseeable maximum travel distance was 100 miles, none of this would be necessary. It is very unlikely you or 99% of the people would need cars. Transportation would be optimized for mass transit/walking/biking. It would probably feel less crowded than current day brooklyn.
Business travel (ie, flights, currently). Less than shipping, but still frequent.
Vacation travel. More frequent than business, but likely shorter distances (still often above 100 miles, though). Though I know of over a dozen people in my circle of friends who have travelled over 1000 miles to get to their spring / summer locations. And these are relatively poor college students.
The problem isn't based around an expected increase in frequency (though there would be, as things are closer), it's that a large number of people do need such large-scale transports, and shoving more of everything together brings up new problems (look at Chicago, the roads & tracks are fairly nightmarish in many places).
Shipping could have a parallel system at the high speed and moderate speed, using shipping containers and (while we're at it) automated transfer systems for the containers. Maybe the whole place could be rigged up like a giant FedEx shipping center, with hundred-mile-long conveyor belts.
Pretty much the same goes for most of your food too.
Water is the only thing that would get tricky. But large chunks of the northern hemisphere have A LOT of water. Think Seatle, or for that matter, ALL of New England, especially northern New England.
This would result in mind bogglingly large population growth, which Earth can't take right now. We need LESS dense populous, not more.
You'd need government or fences or armed forces preventing people from expanding- it is natural for people to expand.
Maybe I am incorrect in thinking so, but my idea was that while the birth rate may be lower, we'd (in the end) approach a higher net population density if we slowly sprawled from a single super-dense hub.