Although most of the world’s cargo moves by ship, focusing on land may be the best way to reduce the carbon footprint of freight.

Transportation is already one of the world’s biggest sources of greenhouse gases, and its emissions are predicted to grow dramatically, says Josué Velázquez Martínez, research scientist at the MIT Center for Transportation and Logistics. A major reason why is freight: the planes, trains, trucks, cargo ships, and other vehicles used to move billions of tons of cargo around the world. Freight transportation makes up 8% of global greenhouse gas emissions and its carbon emissions may double by 2050.

Velázquez Martínez says the best way to reduce freight’s carbon footprint is to focus on what is called the “last mile”—the trucks and vans that carry goods from regional distribution hubs to local stores or homes. Even though most of the world’s cargo travels by sea, these land vehicles have an outsized impact on carbon emissions: road freight emits more than 100 times as much CO2 as a cargo ship to carry the same amount of stuff the same distance. And road freight is growing quickly, in part because of the rise of e-commerce, which has accelerated the number of packages delivered to homes.

Fortunately, trucks and vans are good candidates for the use of greener technology. Current alternatives to CO2-emitting oil-based fuels, such as battery-electric power, are not practical for huge vehicles like airplanes and cargo ships, but can easily power road vehicles traveling shorter distances within a city. However, simply building more electric trucks is not enough, Velázquez Martínez says. The world also needs large investments in clean energy sources such as wind and solar, so that the energy needed to charge all those trucks does not come from fossil fuels.

Because of the high cost of energy infrastructure and new vehicles, he adds, this strategy won’t work in every region or country. That’s why a crucial part of Velázquez Martínez’s research involves working with smaller companies to make their diesel-powered delivery trucks cleaner and more efficient. He does this by analyzing the best routes for trucks to drive and figuring out the ideal speeds for them to maintain so that trucking companies can reduce both the total number of miles driven, and their CO2 emissions per mile. “We’re using intelligence and analytics to try to make the best of already having a fleet that is not necessarily the best,” he says.

Another piece of the puzzle is us—the people who buy goods and, increasingly, have them delivered to our homes. “The consumer has a huge say in this,” Velázquez Martínez says. Today, the environmental impacts of e-commerce are mostly hidden from buyers. But he imagines a shopping experience in which a buyer could see, for example, how much less CO2 would be emitted if they chose a slower delivery method. That way, the shipping company might not need to put the package on an airplane or send multiple trucks to the same neighborhood on the same day.

Many major corporations, from Amazon to L’Oréal, have begun to make large renewable energy investments and commitments to emission reductions in their freight and logistics operations. Velázquez Martínez credits climate accords such as the Paris Agreement for this change, along with other factors: Companies now face pressure to emit less carbon from shareholders and investors, and from shoppers who want to buy from companies that embrace climate responsibility.

Published September 2, 2021.