When it comes to global freight transportation, two modes stand out: maritime and aerial, with the former representing over 80% of trade volume. However, understanding the environmental implications associated with these transportation methods is essential. Analyzing the environmental impact of sea transport (slower but handling larger volumes) and air transport (faster but with smaller quantities) allows for an assessment of the various advantages and disadvantages of both methods from a sustainable perspective.
By Sea: Less Fuel, Fewer Emissions
Maritime transportation is known for its efficiency in carrying large quantities of goods over long distances. From an environmental standpoint, there’s no doubt: ships emit less carbon per unit of cargo transported than airplanes, thanks to their lower fuel consumption compared to air freight.
Moreover, technological advances in ship design and the use of alternative fuels such as biofuels contribute to reducing emissions and minimizing environmental impacts, at least concerning the energy source. Some major shipping companies are already incorporating biofuels into part of their container ship fleets, aiming to make transportation more sustainable and introduce green energy into their operations. As in other sectors, the year 2050 emerges as a significant target.
By Air: Faster, More Emissions
On the other hand, air transport has the significant advantage of speed and global connectivity but is also associated with higher environmental impacts. Airplanes emit substantial amounts of greenhouse gases, especially carbon dioxide (CO2), as well as pollutants like nitrogen oxides (NOx) and particles. The high fuel consumption and emissions per unit of cargo make air transport less environmentally friendly compared to maritime transport, at least in this context.
In terms of carbon footprint, maritime transport has a clear advantage over air transport. Estimates suggest that maritime transport produces approximately 15 to 25 times fewer carbon dioxide emissions per kilogram-kilometer compared to air transport. However, the airline industry has more advanced practices for offsetting the industry’s carbon emissions.
Not All About Emissions
Many specialists explain that, in reality, this clear advantage of ships may conceal some problems with maritime transport. These issues may be related, for example, to the polluting discharges they release into the waters: from cleaning chemicals to plastics, seas are filled with waste and products that harm them. Cargo ships share some responsibility for this.
In this context, the ship crews themselves are a pollution factor, especially in the seas. During trips that can last weeks or even months, the people who live and work on the ships also leave a considerable carbon footprint and pollution.
Additionally, another factor must be taken into account. Despite the vast distances ships can cover, once they reach the port, their products need to be distributed. In many cases, these transfers are made by trucks, significantly increasing the environmental impact of that cargo. Freight train projects that can compete with road transport and also reduce emissions are far from being widespread.
Goods That Can’t Wait
Another key factor has to do with the type of cargo being transported. The characteristics of air transport demand make it a sector facing a significant challenge, involving the transportation of high-value and often perishable products that can deteriorate during a long sea journey.
One example is medicines. Those requiring refrigeration or special care may be compromised if the transportation is not fast and efficient. With the emissions involved in their production, if they were to spoil, they would cause a much more considerable carbon footprint than air transportation. This is where air transport can be more efficient.
By Plane, Directly to Destination
Another significant advantage of air cargo transport is that it allows for a direct connection between the destination and origin. This can save thousands of kilometers of land transportation, reducing the amount of emissions that land transport, generally less efficient, may cause throughout the process.
While air transport offers fast and urgent deliveries, this often entails a higher environmental cost. The choice between maritime and air transport depends on various factors, including the nature of the cargo, urgency, cost considerations, and environmental priorities. In some cases, a combination of both modes, known as multimodal transport, can be used to optimize efficiency and minimize environmental impacts.
