Environmental regulations have greatly reduced the amount of sulfur in
gasoline. This has created many benefits. But did you ever
wonder what happens to all that sulfur? Perhaps not, if it was
never clear to you why you should care.
The reason you should care is this: Sulfur is present in coal and
in most liquid fuels. When it is burned, it oxidized, much as the
carbon is oxidized. Carbon becomes carbon dioxide; sulfur becomes
sulfur dioxide. When sulfur dioxide enters the atmosphere, it
becomes a strong acid: sulfuric acid, which is battery acid. This
is one factor that contributes to href="http://en.wikipedia.org/wiki/Acid_rain">acid rain, among
Regulations in the USA and elsewhere have resulted in a great reduction
in domestic sulfur emissions. In part, this is because oil
refineries limit the amount of sulfur that goes into gasoline and
diesel fuel. But the sulfur, being an element, does not just go
away. Have environmental regulations solved the problem?
Hardly, explains Fred Pearce, environmental consultant to New Scientist
16 ships create as much pollution as all the cars in the world
By Fred Pearce
21st November 2009
...We've all noticed it. The filthy black smoke kicked out
by funnels on cross-Channel ferries, cruise liners, container ships,
oil tankers and even tugboats.
It looks foul, and leaves a brown haze across ports and shipping lanes.
But what hasn't been clear until now is that it is also a major killer,
probably causing thousands of deaths in Britain alone.
As ships get bigger, the pollution is getting worse. The most
staggering statistic of all is that just 16 of the world's largest
ships can produce as much lung-clogging sulphur pollution as all the
Seems improbable, at first glance. But then, there are some
really big ships out there. Pearce explains that the largest
ships are a quarter-mile long. The biggest are the href="http://en.wikipedia.org/wiki/Emma_M%C3%A6rsk">Emma MÃ¦rsk-class
container ships. Their main engines weight over 2,300 tons, and
produce 114,800 hp (84 megawatts). They also have five smaller
engines that together produce another 40,000 hp.
Pearce explains how these things are powered:
Because of their colossal engines, each as heavy as a small
ship, these super-vessels use as much fuel as small power stations.
But, unlike power stations or cars, they can burn the cheapest,
filthiest, high-sulphur fuel: the thick residues left behind in
refineries after the lighter liquids have been taken. The stuff nobody
on land is allowed to use.
James Corbett, of the University of Delaware, is an
authority on ship emissions. He calculates a worldwide death toll of
about 64,000 a year, of which 27,000 are in Europe. Britain is one of
the worst-hit countries, with about 2,000 deaths from funnel fumes.
Corbett predicts the global figure will rise to 87,000 deaths a year by
The article does not describe the effects of the sulfur emissions upon
the oceans. That is where the majority of the emissions
occur. The International Maritime Organization "limits" the
emission of each ship to 5,000 tons of sulfur per year. Someone
else can do the math, but this would seem to be a factor that
contributes to the href="http://scienceblogs.com/islandofdoubt/2009/01/blowing_the_whistle_on_ocean_a.php">acidification
However, most of what I found on that subject attributes the
acidification to carbon dioxide.
Pearce does make a questionable claim, however:
The recession has barely dented the trade. This Christmas,
most of our presents will have come by super-ship from the Far East;
ships such as the Emma Maersk and her seven sisters Evelyn, Eugen,
Estelle, Ebba, Eleonora, Elly and Edith Maersk.
London-based Drewry Shipping Consultants forecasts a
year-on-year fall of 10.3 per cent in containers moved this year,
compared with 4.6 per cent growth in 1982, the previous worst year
since 1956, when container shipping started.
To be fair, the FT article was published after Pearce's article, so I
don't fault him for this.
So, is the recession going to be good for the environment? Pearce
addressed that question in a separate href="http://www.newscientist.com/blogs/shortsharpscience/2008/10/what-does-the-credit-crunch-me.html">article:
Global recession is going to have two effects - pulling in
opposite directions. The economic downturn will reduce fuel burning and
so cause a slackening off in the recent inexorable rise in emissions of
carbon dioxide. It happened in the 1930s; it will happen now.
That's the good news. The bad news is that, as the cost of fuel plunges
(oil is back under $80 a barrel already), the incentives to use less
and to switch to renewables will evaporate. Cheap coal will trump clean
coal - let alone solar panels and wind turbines.
Conservation costs money. Money is increasingly hard to
get. Nobody can predict how the two forces will play out.
Will the decline in economic activity lead to lasting, overall
reductions in pollution? Or will the need to cut costs result in
a return to dirtier ways of doing business, offsetting the