Ever since the Hindenburg collapsed in flames in 1937 over New Jersey, killing dozens, airships have had a really bad rep. But some researchers believe that modern hydrogen-based zeppelins are much safer and could prove practical for carrying cargo across the world instead of using huge cargo ships, which are very taxing for the environment.

Writing in the journal Energy Conversion and Management: X, researchers at the International Institute for Applied Systems Analysis in Austria envision a future where gigantic airships, more than five times as long as the Empire State Building is tall, will soar high in the atmosphere carrying more than 20,000 tons of cargo.

Today, maritime shipping accounts for 90% of traded goods — and all those cargo ships are emitting a boatload of carbon emissions. Airships, on the other hand, would emit only a tiny fraction of that since they’d be essentially powered by jet streams.

The Northern Hemisphere polar jet stream is a belt of powerful upper-level winds that sits atop the polar front. An airship taking off from the United States would basically ride the jet stream, crossing the Atlantic Ocean to Europe. It could then catch the stream again to reach Asia, load cargo in China, then continue its journey crossing the Pacific to return home.

Although aircraft dominate passenger flights and shipping by air, there are still airships around. These are mainly used as huge billboards (i.e. Goodyear blips) and for luxury travel.

Unlike the Hindenburg, these zeppelins are safe because they employ helium, an inert gas, instead of the highly reactive hydrogen. The problem with helium, though, is that it’s the second lightest chemical element in the Universe — so light that it can’t be kept by Earth’s atmosphere, and thus floating into space whenever it gets the chance to escape.

Most of the helium we use today is found in gas pockets trapped inside the planet, typically obtained as a by-product of oil extraction.

According to a 2010 study, all of the known helium reserves should run out in the next 25 years. Bye, bye helium balloons — unless you’re prepared to pay hundreds of dollars for one.

Meanwhile, hydrogen is a renewable resource. You can obtain it by refining methane or, better yet, using solar panels to trigger electrolysis that splits water molecules, thereby obtaining hydrogen that is 100% clean for the environment.

Any airship meant for carrying cargo would, therefore, have to be filled with hydrogen — no other gas makes economic sense for this kind of application.

Carbon fiber, sensors, and other modern materials and equipment can mitigate many of the risks associated with hydrogen zeppelins. But that doesn’t mean people wouldn’t be scared.

Although exciting, cargo zeppelins face two huge challenges. One has to do with designing an airship that’s nearly a mile and a half long (2.4 km) — that surely won’t be easy or cheap to build. Secondly, the hydrogen component means there are many regulatory hurdles that have to be overcome. For instance, airships filled with hydrogen have been banned in the United States since 1922. Many other countries followed suit after the Hindenburg disaster.

The authors of the new study say that the cargo zeppelins could be fully autonomous and loading and unloading could be performed by robots. This way, no crew would be in danger if an accident were to happen.

But all of this means that it will be highly difficult to find investors willing to bet on such a high-risk technology. The prospect is appealing, nevertheless, as any kind of new approach to cutting shipping emissions is very much welcomed.

The United Nations Conference on Trade and Development expects trade to continue to grow in the coming decades. And as trade grows, carbon dioxide emissions from international shipping could increase by as much as 250 percent by 2050.