Unless the number of each of those "billions" is only 2, then that's just about the entire human species.

If 90% of humans were killed in a nuclear exchange (or any other mass death event), we'd still have a population considerably higher than it was 2000 years ago.

If 99% of humanity were killed, we'd still have a population considerably higher than it was 3000 years ago....

England have about 16.000 miles (kilometers? I don't remember) of coast. The proposed generators will take about 30 miles. There will be plenty of coast left to all marine species. It's not a full perimeter siege, it's just a few barricades here and there.

The USA has thousands of miles of coastline too. Alas, salmon were only interested in a tiny fraction of those thousands, and the dams built on that tiny fraction were a major problem for salmon.

So, what's going to be the problem fish/crustacean/whatever for these installations?

it may not be continuous 24/7 but you get it between 4pm and 10pm

Some days you do, some you don't. Tides happen at about 12 hour and 40 minute intervals. So the period that you have tidal power drifts around the clock over a lunar month....

During the peak production hours of the tidal generators, the coal and oil plants can be shut down, decreasing pollution and cutting production costs.

Hmm, 14 hour uptime per 24 hours and change. Which means up for seven hours, down for 5.3 (or so) hours, up for seven hours, down for 5.3 (or so) hours.

First off, you can't shut down a coal power plant and restart it in only five hours. And it will operate at considerably (for values of "considerably" that vary from 10% to 30%) reduced efficiency for some hours after startup

Secondly, pollution from coal plants are 30%-50% (or so, depending on type of pollutant) higher during the 24 (or so) hours immediately after startup.

Which means that you're basically reducing efficiency of your coal plant in exchange for getting more pollution out of it.

In other words, that won't work.

Note that both points in your quote are quite true.

The North Vietnamese never beat the US on the battlefield and lost the war with the US.

Alas, once the US went home, there was a SECOND Vietnam War, with the sides being USSR+North Vietnam vs South Vietnam. The North won that one.

It's one of the things that can happen when you decide to quit fighting unilaterally.

I've never noticed that non-religious types were less prone to hypocrisy than the religious variety, actually.

As to the nine-year-old thing, "accepted customs of our tribe" actually covers that - it WAS perfectly normal to marry females approaching puberty there and then. Now, not so much (though I have read the marriage of 13-15 year old girls wasn't uncommon as recently as 200 years ago).

though there were idiots like Columbus who were convinced the world was much smaller then the generally accepted size.

There is a certain amount of evidence that Columbus lied about how big he thought the world was, in order to convince the Spanish crown to finance his expedition.

It's not like the New World was completely unknown in Europe before Columbus - FLemish fishermen were drying fish in Newfoundland before Columbus was born. And it's quite possible that Columbus knew that.

If so, and in light of Spain's interest in breaking the Portugese monopoly on trade with the Far East, a little "creative interpretation" of the world's size might have been sufficient to convince the Spanish Crown that a trip west was a worthwhile investment....

Isn't population growing mainly due to latency?

Not quite.

In the developed world, population growth is negative absent immigration. Currently, this applies to China, the EU, and the USA. Last I bothered to check, the projections were for continued global population growth up to the 10-15 billion range, followed be a decline to a stable population in the 5-9 billion range.

Note that that "stable population" presupposes that the entire world is "developed" by that time.

If owning robot overlords can assure you all you ever need without working, it's obvious everybody will want these, but only the most fortunate will afford it, leaving the rest of us in misery.

If we don't have robots making our shit, then we'll still be making it the old-fashioned way, which sort of implies we'll be working for a living.

At least until we can set up robot factories of our own, of course.

Look at it this way - if the robots can make enough stuff for everyone to have everything they want, then everyone will be "rich". Of course, the real problem in that case is that we'll stop measuring "wealth" in "things we own"....

Also note that even if the (currently) wealthy types make just enough stuff for themselves and leave the rest of us to rot, there's nothing actually stopping the rest of us from building our own robots to make shit for us....

Yes, and now that the rentiers will make even more money for no labor, the displaced workers are doubly fucked.

And how, pray tell, will the rentiers make even more money if noone can afford to buy what they make because they're unemployed?

Oddly, we seem to have managed to get past the introduction of the assembly line without the sort of problems you're predicting - humanity is still here, its population is still growing, and technology is still advancing.

Quit wasting my fucking tax money on your hair-brained ideas.

Harebrained.

Brains don't have hairs, but hares have brains....

Wasn't that Senator Obama?!?!?!

Not in JAN 2014 it wasn't. Or did you think he was elected President late last year?

If they paid more taxes I would pay less

No, if they paid more taxes, the government would increase its spending to match the increased revenues.

So there's coastal cities and there's "flat as a pancake cities that are 1 meter above sea level"

And then there's New Orleans. Average height above Sea Level is MINUS 0.5 meters. Range is 6m above to 2m below.