
Shipping is one of the dirtiest industries, but these new innovations could make an important difference. The HullSkater is a magnetic crawling robot that cleans the hulls of ships. It removes biofouling -- the build-up of organisms which stick to ships and cause drag, which increases fuel consumption and carbon emissions. Scroll through the gallery to see more technology that could ease the impacts of shipping and sea travel on the planet.

Wind-powered ships: Wallenius Marine, a Swedish shipbuilder, is designing a wind-powered car carrier. It says the 650-foot-long vessel -- which has capacity for 7,000 vehicles -- cuts carbon emissions by 90%, compared to a standard car carrier.

Biofuels: Biofuels are one way to green the shipping industry. These fuels are made from plants, algae, animal waste, or waste materials, and are considered a source of renewable energy. The Mette Maersk, a container ship from Denmark, ran on a blend of fuel oil and biofuels, made from cooking oil, during a three-month round trip from Rotterdam to Shanghai.

Driverless boats: Norway has pioneered electric ferries since launching the world's first electric passenger ferry in 2015. Now some ferries in the city of Trondheim will be driverless, too. Developer Zeabuz says its autonomous zero-emissions ferries will launch next year.

Hydrogen powered boats: "Hydroville" is the world's first sea-faring vessel to burn hydrogen in a diesel engine. This means no carbon dioxide or sulfur oxides are released when the boat is used. The silent zero-pollution boat is built by Belgian company Compagnie Maritime Belge.

Underwater tunnels: To cut travel time in half, the Norwegian government is planning an ambitious $40 billion infrastructure project including submerged floating tunnels. The plan aims to improve the journey between the cities of Kristiansand and Trondheim and make the route "ferry-free."

Using shipping containers as farms: These tiny indoor farms grow food in old shipping containers in parking lots in Brooklyn, New York. Square Roots, the company that developed the technology, says its models use less food miles and create less food waste than regular farming.