“If all the ships on Earth were a single country, that country would be the sixth-largest polluter in the world.” This shocking fact comes from a recent NPR report by the Short Wave science podcast that delves into the dirty business of shipping, which as an industry ranks just behind Japan in its pollution levels. This is partly because of the gargantuan scale of the shipping industry, but it’s also in large part because these massive ships burn a particularly dirty heavy fuel oil, also known as bunker fuel. 1

One of the World’s Dirtiest Industries – Maritime Shipping

The Third IMO GHG Study (2014) estimated that for the period 2007-2012, shipping emitted about 1,000 Mt CO2 per year, equaling approximately 3.1% of annual global CO2 emissions. The latest update to the study by CE Delft projects shipping emissions to increase by up to 120% by 2050 if other sectors decarbonise successfully.2 Shipping also contributes to climate change through emissions of Black Carbon, tiny black particles, produced by combustion of marine fuel. The highest amounts of black carbon particles are produced by ships burning heavy fuel oil. Black carbon accounts for 21% of CO2-equivalent emissions from ships, making it the second most important driver of shipping’s climate impacts after carbon dioxide.2

Importance of Renewables to Reduce Shipping Emissions

Although this industry is incredibly dirty, there are motions in place to try to change that. In fact, Maersk, the largest shipping company in the world, has promised to go zero carbon by 2050.1

One of the best renewable answers to maritime shipping’s dirty problem are hydrogen fuel cells. Thanks to their success in heavy-duty land vehicles, fuel cells are now being integrated into marine vessels. Fuel cells will play a key role in helping marine industries address greenhouse gas (GHG) emissions on the water, and in ports. Like batteries, fuel cells produce electricity with high efficiency through an electro-chemical process. Energy is stored separately in the form of hydrogen fuel. As long as fuel is available, the fuel cell power systems will produce electricity as a generator, and the only emissions from a fuel cell are water vapour and heat.3

There are of course other options to complement renewable energy, and one of them is port-based incentive schemes. Financial incentives at the port level could provide important lessons for the design of decarbonisation policies for the maritime sector.4

 Something needs to be done about reducing greenhouse gas emissions caused by shipping. We are hopeful that the world can see the damage being inflicted, and that all shipping companies will make the switch to renewable sources in the near future.


1Zaremba, Haley. (Nov. 8, 2019). The Renewable Solution To One Of The World’s Dirtiest Industries. Retrieved from Nasdaq.com: https://www.nasdaq.com/articles/the-renewable-solution-to-one-of-the-worlds-dirtiest-industries-2019-11-08

2European Federation for Transport and Environment AISBL. (2019). Shipping and climate change. Retrieved from transportenvironment.org: https://www.transportenvironment.org/what-we-do/shipping-and-environment/shipping-and-climate-change

3Mace, Alan. (March 28, 2019). Here’s Why Fuel Cells Will Power the World’s Marine Vessels. Retrieved from blog.ballard.com: https://blog.ballard.com/fuel-cells-marine-vessels

4International Transport Forum. (2018). Reducing Shipping Greenhouse Gas Emissions. Retrieved from itf-oecd.org: https://www.itf-oecd.org/sites/default/files/docs/reducing-shipping-greenhouse-gas-emissions.pdf