Dirk Meussling/Star Clippers

Editor’s Note: Monthly Ticket is a CNN Travel series that spotlights some of the most fascinating topics in the travel world. In February, we’re exploring the people, places and journeys working to make tourism more sustainable.

CNN  — 

For travelers who love to cruise but also consider themselves to be environmentally minded, the concept of “green” cruising can seem counterintuitive.

Indeed, sustainability challenges abound in an industry known for its carbon-spewing vessels, excess waste production (spanning trash, sewage, and gray water), and port overtourism – not to mention environmental violations that have resulted in well-publicized penalties.

However, as stricter regulations and global environmental benchmarks set in – and consumers increasingly demand cleaner, greener vacations – there are cruise companies out there that are putting the hard work into making at-sea experiences significantly more sustainable.

“Every cruise line is investing in green initiatives, from looking at carbon footprint to refining emissions. It is top of mind for each cruise line,” explains Colleen McDaniel, editor-in-chief of cruise review website Cruise Critic.

And today, baseline sustainability practices like banning plastic straws or reusing linens simply aren’t enough to move the needle. The real innovators are the lines that are most aggressively chasing decarbonization goals via technological breakthroughs, especially around cleaner alternative fuels and greener infrastructure in port.

The cruise industry transported nearly 30 million passengers and contributed over $154 billion to the global economy pre-pandemic, in 2019; despite the hiccups of the pandemic, it’s on track to surpass those numbers by year’s end. Cruise proponents say that cruising can be a force for good, by supporting local economies and inspiring cruisers’ sense of environmental and cultural awareness.

Yet, the industry’s reliance on polluting heavy fuel oil (HFO) for its ships has put it at odds with the United Nations’ global net-zero emissions targets for 2050. Currently, cruise ships and other maritime vessels are responsible for nearly 3% of global greenhouse emissions each year. Considered to be worse than flying in terms of carbon emissions per passenger, a report by Pacific Standard revealed that a person’s average carbon footprint triples in size while on a cruise.

Ocean-going member cruise lines of Cruise Lines International Association (CLIA), the largest cruise industry trade association, have committed to reaching net-zero carbon emissions by 2050, and to reducing carbon rates by 40% by 2030 (as compared to 2008 levels).

As those goals are targeted, however, industry watchdogs say greenwashing abounds. “Many of the claims of sustainability are just greenwashing or are the same types of ‘sustainability’ measures that have been happening for years in land-based tourism,” says Marcie Keever, a director at environmental group Friends of the Earth, which puts out an annual cruise line “report card.”

Examples of this may be found as lines look to swap out carbon- and sulfur-emitting HFO for cleaner, alternative fuels. Lower-carbon liquefied natural gas (LNG) is being widely heralded as a “stepping stone” fuel solution, with more than half of the new cruise ships on order with CLIA members featuring LNG for their primary propulsion.

Yet, environmentalists and scientists caution that LNG it is a finite and polluting fossil fuel that may cause even more environmental damage than HFO long-term.

Simply put, “LNG is a dirty fuel,” says Dr. Mark Jacobson, director of the atmosphere/energy program at Stanford University, and author of “No Miracles Needed: How Today’s Technology Can Save Our Climate and Clean Our Air.” He says that while LNG’s “direct air pollution emissions are less than heavy fuel oil, they are still substantial – and its upstream emissions and footprint are larger than of heavy fuel,” owed to factors like unsustainable extraction practices (like fracking) and methane byproducts.

Experts like Jacobson say the industry’s focus should be more fully on emerging zero-emissions energy technologies. “The far cleaner solutions for ships are battery electricity and green hydrogen fuel cell electricity,” says Jacobson, citing that “in either case, all emissions from the ship – aside from water vapor in the case of hydrogen fuel cells–are eliminated.”

CLIA reports that more than 15% of cruise ships debuting in the next five years will be equipped to incorporate hydrogen fuel cells or electric batteries.

Another promising sustainability development is the industry’s move toward zero-emissions docking. The vast majority of today’s new ships are being designed with capabilities to power off their fuel-burning engines and plug into the local grid while in port – reducing air pollution and related health issues in the process. The caveat: Only 29 of the 1,500-odd ports visited by CLIA ships presently offer compatible infrastructure.

While there may be a long way to go yet – “cruising continues to be one of the dirtiest vacation choices,” cautions Keever – here are five cruise lines that are leading the pack with their eco-conscious initiatives.

Hurtigruten

Ole Martin Wold
Hurtigruten was the world's first cruise company to phase out single-use plastics onboard.

This 130-year-old Norwegian adventure travel company incorporates a sustainability ethos at its core. A green-energy leader, Hurtigruten sidelined HFO for its small-ship fleet over a decade ago, in favor of alternative, greener fuels like marine gasoil and biofuels.

In 2019, they launched the world’s first hybrid battery electric-powered cruise ship (and are in the process of converting the rest of their expedition fleet to hybrid battery power), with plans for the world’s first zero-emissions cruise ship by 2030.

They’ve also enabled fleet-wide shore-power connectivity to eliminate emissions while in port, and were the first cruise company to phase out single-use plastics onboard.

Ponant

Gilles Trillard
The first cruise line to achieve Green Marine certification, Ponant also offsets 100% of its emissions.

Luxury French line Ponant rolled out an emissions-slashing hybrid expedition ship (running on LNG and electric battery power), the 245-passenger Le Commandant Charcot, in 2021, and has plans for a “zero-impact” ship by 2025.

The first cruise line to achieve Green Marine certification, Ponant also offsets 100% of its emissions.

Plus, all Ponant ships are equipped with shore-to-ship power connections in port; the line has stopped using single-use plastics; and environmental impact studies are conducted before designing any itinerary.

Star Clippers

Star Clippers
Star Clippers' tall ships operate exclusively on wind power up to 80% of the time.

Sometimes, when it comes to sustainability, what’s old is new again.

Monaco-based sailing company Star Clippers operates a trio of tall 166- to 227-passenger sailing ships that operate exclusively on wind power up to 80% of the time (and utilize low-sulfur gas oil otherwise).

Small ship size means lesser overall impact, as well as access to less-touristed ports–in Costa Rica, for instance, Star Clippers was the first cruise line to be certified as “Pura Vida Pledge”-approved by the Costa Rican Tourism Board in recognition of their eco-credentials.

Havila Voyages

Havila Voyages
Havila Voyages' hybrid ships can operate on battery-power for periods of up to four hours.

This 2022-debuted Norwegian cruise line has launched two of four planned hybrid ships, running itineraries along Norway’s coast.

Havila Voyages has the biggest passenger-ship batteries at sea, allowing their ships to voyage – for periods of up to four hours – into the country’s UNESCO-protected fjords, silently and emissions-free.

Plus, the batteries can be recharged in port with clean hydropower energy from the local grid, and are strong enough to power the ships while they’re docked. While the ships currently also use LNG power, Havila aims to ultimately run emissions-free, with vessels that’ve been designed to cross over to hydrogen power once the technology is available.

Explora Journeys

Explora Journeys
Explora Journeys will launch the the world's first LNG-powered vessel to feature hydrogen fuel cells in 2027.

This new luxury cruise brand from Swiss-based shipping company MSC Group launches this summer, but will really make waves in 2027 when it debuts the world’s first LNG-powered vessel to feature hydrogen fuel cells, along with methane slip-reducing technology.

In partnership with Italian shipbuilders Fincantieri, Explora Journeys’ pioneering ships (the first that of two that are planned for the fledgling line) will have significantly reduced greenhouse emissions while at sea and emit little more than water vapor and heat when idle in port.

Other highlights for the brand include a single-use plastics ban and underwater noise reduction certification (as not to disturb marine wildlife).