Globally, shipping is responsible for 2-3% of all greenhouse gas emissions (GHGs) emitted by human activity  - close to 1 billion tons of CO2 per year. This titanic, outsized influence is mainly due to a lack of regulation or other incentive for shipping lines to improve their energy efficiency and upgrade their fuel source from the heavy fuel oil typically used today. This cheap, dirty “bunker fuel” not only produces relatively more CO2 per unit of energy than gasoline or even diesel : it also contains high amounts of toxic compounds such as sulphur oxides and nitrogen oxides; one large container vessel can generate the annual sulphur dioxide emissions of 19-180 million cars .
The objections raised by the industry to calls for reform have mostly focused on the financial implications of “cleaner” sources of energy, and the inherent problem of retrofitting existing vessels to make use of them. Nevertheless, effective 2020, the International Maritime Organization (IMO) has imposed a 0.5% cap on sulphur oxide concentrations , in an effort to kickstart much-needed environmental reformation within shipping. The IMO’s decision has sent a shockwave across a rigid industrial zeitgeist that views major disruptions such as this as challenging and unnecessary, and shippers’ immediate concerns for profitability in the fuel cap’s wake, whilst arguably short-sighted and introspective, are nonetheless realistic.
Irrespective of fuel quality, though, there are other aspects of modern shipping which possess significant room for improvement. The movement of empty containers, which creates no value for shipping lines, has been a longstanding burden for the industry; the costs associated with repositioning these empty containers is in the region of US$15-20 billion per year , and up to one-third of all container journeys are being made empty .
Whilst the energy cost of moving a full unit is naturally higher, an empty container still weighs 2-4 metric tonnes , and still requires transportation by road/rail/sea as well as handling by (still mostly diesel-driven) cranes. Corollary factors, such as path inefficiency and equipment breakdown, only add to the environmental burden of containerized transport. All in all, at least 10% of the container’s total emissions could be prevented merely by ensuring it spends less time in unnecessary transit, using systems and techniques available today.
Pro rata, each 40’ container shipped is responsible for roughly 2-4 metric tonnes of CO2 in associated emissions; half of this will come from the first and last road-based portions of its journey, which represent only a small fraction of the total distance travelled.
Many of those who read that last statement will now be wondering “so what?”; indeed, it is difficult to internalize the real-life consequences of this “load of hot air”. Here’s a more grounded comparison: every time you move a 40’ container, say, from Beijing to London, you’ll need at least 150 young trees to grow and “work” for a whole year, just to compensate for the emissions produced. To compensate for the total carbon cost of moving their boxes around the world, container owners would have to collectively plant and nurture a forest the size of Belgium .
The merits of covering Belgium in a sea of trees to tackle climate change are debatable, particularly for the people of Belgium. Nonetheless, what is clear beyond doubt is that wasting time benefits no one; we haven’t got much left . Regardless of your personal opinion on the sulphur cap, shipping emissions and the advent of sustainable logistics - repositioning poses a clear and immediate problem to everyone who owns or operates a container. Despite the industry’s continuous efforts at fleet optimization, there is still a very long way to go.
Shipping lines have little to lose and plenty to gain from taking a closer look at how their boxes move, why their boxes move, and what they could do better that they’re not doing already. From these small changes in strategy, in fact, we all have plenty to gain.
 Cabuzel, T. (2019, July 1). Commission publishes information on CO2 emissions from maritime transport. Retrieved October 17, 2019.
 Volker Quaschning (Ed.). (2015, June). Specific carbon dioxide emissions of various fuels.
 Aminoff, T. (2019, January 22). Does one ship pollute as much as 50 million cars?
 Sulphur 2020 – cutting sulphur oxide emissions. (n.d.).
 Sanders, U., Riedl, J., Kloppsteck, L., Roeloffs, C., & Schlingmeier, J. (2015, November 17). Think Outside Your Boxes: Solving the Global Container-Repositioning Puzzle.
 Wollenhaupt, G. (2018, October 30). Uber for empty containers could solve repositioning challenges.
 - DSV (Ed.). (n.d.). Dry container dimensions.
 Based on figures from: Carbon Neutral (Ed.). (2017). FAQs.
 Watts, J. (2018, October 8). We have 12 years to limit climate change catastrophe, warns UN.