How could we replace cargo ships (and airplanes) with a less pollutive way of intercontinental transportation?

Let’s take the opening paragraph from the attached article from wiki -

“The environmental impact of shipping includes air pollution, water pollution, acoustic, and oil pollution. Ships are responsible for more than 18 percent of some air pollutants”

That’s actually rather good, considering that international shipping transports 90% of everything that you and I and the rest of the world use. Ninety Percent of Everything by Rose George

As Austin Bugden rightly says, shipping is the most efficient way of transporting large volumes of cargo around the world, and it’s the reason why it is less polluting than vehicular traffic or any other means of transportation. There’s another article out there that states one ship produces more pollution than all the road vehicles in the world or something similar, but you wouldn’t be able to drive those vehicles if shipping didn’t get them to wherever they are used in the first place.

Car carrier - of which more later (image - VW)

In the days of sail, bulk cargoes were carried around the world by the trade winds, so called because trade used them as motive power for their ships. Whilst some of these were capable of 18 knots in a good blow, they could also be becalmed for two weeks outside a port waiting for a favourable wind to start their passage to the other side of the world. Two weeks… Think about that, and how far a powered vessel such as a container ship could travel at 20 knots in the same time. To save you working it out, it’s 6,720 nautical miles - about a quarter of the way round the world on the equator, whilst the sailing ship is still sitting outside Belfast (as happened to Moshulu in that great book “The Last Grain Race” by Eric Newby). On the way “east about” to Australia, the same ship could also sit in the “doldrums” for days or weeks on end, steadily running short of food and water.

Enter King Coal. The great Victorian and Edwardian engineers at the end of the 19th and beginning of the 20th century revolutionised sea transport by driving ships burning coal. The doldrums were a thing of the past, and steamships travelled the world, opening it up as never before, not only to cargo but also to passenger traffic.

RMS Mauretania 1907 - the last word in speed and pollution (Wiki)

King Coal ruled the waves until the early 20s, when large steamships such as Mauretania above converted to oil, and those large volumes of choking smoke were reduced considerably - though still continued on land (and still do in some countries).

Enter now on our watery stage, the diesel engine -

Not only large but also the most efficient engine known to man. The large-bore, single-acting, direct-reversing, 2-stroke marine oil engine (Wärtsilä-Sulzer).

Originally these engines burned a light distillate fuel called “diesel” (figures) but later in the century one CC Pounder of Harland & Wolff (yes, the Titanic people) pioneered the burning of heavy fuel oils in these engines. A ship also has, besides this large propulsion engine, three diesel generators of some 1–1.5MW each in a VLCC, which still burned diesel up until the late 80s, early 90s when even they converted to burning the much cheaper heavy oils. Even through the various oil embargoes by OPEC, and the fluctuation of crude prices worldwide ever since, the burning of fuel that no one else wanted except for building roads, meant that 90% of everything still arrived at your door on time and in sufficient quantities to avoid wartime queueing…

The steamships also burned this fuel, but their days were numbered, and the marine diesel engine’s efficiency has just about finished them off.

So, what’s next? IMO - the International Maritime Organisation - which makes the rules that I and others worked under in our lives as marine engineers and seafarers, has continually striven to reduce the amount of pollution at sea over the years since the inception of MARPOL in 1978 or thereabouts. MARPOL covers all pollutants at sea such as oil, garbage, plastics, sewage, dangerous chemicals etc., with far-reaching rules that are not the case on land, even though they should be as that’s where the majority of the world’s pollution comes from. IMO’s latest regulation covers marine pollution from “NOX and SOX” - oxides of nitrogen and sulphur - in an attempt to reduce the amount of sulphur and other by-products into the atmosphere from ships by 01/01/2020, so not long to go now until it comes into force.

This regulation has “put the cat amongst the pigeons” in the shipping industry, such that owners are faced with either burning expensive low-sulphur fuels, fitting a 5MUSD scrubber or scrapping, converting, or newbuilding to burning the “new” fuel LNG.

LNG is the cleanest burning fuel that is commercially viable at the moment (forget hydrogen and other schemes like nuclear, wind and solar). It’s relatively cheap and burns well in marine engines with little or no pollution. Paradoxically it allowed the resurgence of steamships for a few decades when LNG carriers burned the free cargo boil-off instead of expensive fuel oil in their boilers. Since 2008, these steam LNGC have been superseded by diesel engined LNGC which also burn the cargo but less of it, so it’s “goodbye steam” again.

So where are we now? Carnival, the largest cruise ship company is building ships powered by LNG, and that car carrier I mentioned earlier in this missive is a design for an LNG fuelled ship - Volkswagen to Charter Two LNG-Powered Car Carriers – gCaptain

So, once again, the marine industry leads the way, with the rest of the land-based world still wallowing in its own ordure whilst it continues to blame shipping for the pollution it causes!

I hope that this has set the record straight? If anyone can think of a less pollutive way of intercontinental transportation, I’d like to hear it.