Modern turboprop aircraft [deliver] outstanding reductions in fuel consumption, greenhouse gas emissions and noise.

I'd love to see some figures justifying that statement.  It is common wisdom, but I just don't see it.  I know someone who flys Dash-8s (now "Bombardier Q Series") for a living, and have looked at actual flight plans.  For example, a DHC-8-300 on a 406 nm route, 2:02 gate-gate, fuel burn 2457 pounds.  At 6.84 pounds per US gallon that's 359.2 US gallons, or 1.130 nm/USgallon or, finally, 1.284 statute miles per US gallon, commonly referred to as "mpg".  Even a plane with all 50 seats filled will thus have an efficiency of 64.22 mpg (or, as stated on my page 59.3 mpg gasoline-energy equivalent for comparison with gasoline-powered cars).

This compares to a figure for JetBlue's A320 fleet as a whole of 69.7 passenger-mpg and Southwest's 737 fleet as a whole of 59.8 passenger-mpg.

Yes, the -400 is supposed to be more efficient, but really - how much more?  ANA operates DHC-8-400s as well as A320 and ranks them at roughly equivalent efficiency.

http://www.ana.co.jp/eng/aboutana/corporate/csr/report/pdf/e2004.pdf

I'm not trying to be difficult, just trying to get to the truth of the matter.  I'm prepared to believe that turboprops are more efficient over very short routes, as jets are particularly inefficient at lower altitudes, but there is little scope for improvement here as there are very few short routes in the world served by large jets.

Just as turbo props are more efficient, so are ships.

I'd also like to see some proof of this as well.  I thought so too, but I have yet to find any confirmation of the fact.  The only ocean going ship providing passenger service (as opposed to "cruises") that I've found the numbers for is the Queen Mary 2.  Amusingly, its fuel consumption works out to almost exactly 10 yards per gallon.  With 3090 people on board that's 17.3 passenger-mpg, which is barely better than the Concorde managed.

In some ways it makes sense to me that trans-oceanic travel may actually be more efficient by air than by sea, as the space (and thus mass) per passenger must necessarily be much larger on a ship.  If you could get people to sit in commercial aircraft density seating in a ship that is at sea for weeks then no doubt you would find it is vastly more energy efficient.