The biggest cruise ship globally poses a climate risk

The world’s largest cruise ship, Royal Caribbean’s Icon of the Seas, is set to embark on its maiden voyage on January 27, promising to usher in “a new era of vacations.” However, as massive ships like the Icon add more energy-intensive amenities, concerns about emissions from the cruise industry are rising.

The Icon of the Seas is an impressive vessel, measuring over 1,000 feet in length, weighing around 250,000 gross registered tons, and featuring 20 decks, 40 restaurants, bars and lounges, seven pools, six waterslides, and a 55-foot waterfall. While it aims to redefine luxury cruising, it also underscores a significant environmental challenge—the greenhouse gas emissions associated with cruise travel.

A 2022 analysis by Bryan Comer, the director of the Marine Program at the International Council on Clean Transportation, compared the carbon footprint of a cruise to a hotel stay plus air travel, considering cruises as floating hotels. The study found that a person taking a 1,200-mile cruise on the most efficient cruise line would be responsible for about 1,100 pounds of CO2, roughly double the emissions of a round-trip flight and a stay in a four-star hotel.

Moreover, many cruise passengers fly to their cruise departure ports, contributing to the overall carbon footprint of their vacations. Stella Bartolini Cavicchi, a marine policy advisor at OceanMind, notes that flying to a cruising port results in a “carbon-intensive holiday.”

Royal Caribbean claims that the Icon is designed to operate 24% more efficiently than the international standard for new ships, which already must be 30% more energy-efficient than those built in 2014 according to International Maritime Organization (IMO) regulations. The cruise line plans to monitor the ship’s performance over the next six to 12 months to ensure it meets its efficiency targets.

In 2022, Royal Caribbean’s direct emissions totaled 5.5 million tons of CO2 equivalent, slightly up from 5.3 million tons in 2019. Despite environmental concerns, the cruise industry has seen a resurgence in popularity after pandemic-related restrictions were lifted. The Cruise Lines International Association predicts that passenger volume will reach 36 million in 2023, up from almost 32 million in 2022.

Cruise ships not only emit greenhouse gases but also release black carbon, a soot-like substance that absorbs sunlight and contributes to the melting of glaciers, particularly in Arctic regions where cruises are becoming more common. While cruise ships account for about 1% of the global fleet, they are responsible for 6% of black carbon emissions.

Cruise companies have pledged to achieve net-zero emissions by 2050, with many replacing oil-based fuels with liquified natural gas (LNG). However, investigations have revealed that LNG-powered ships may leak methane directly into the atmosphere, a potent greenhouse gas. Cruise operators are urged to explore more sustainable fuels, such as methanol, to reduce their environmental impact.

The maritime industry, including the cruise sector, is facing pressure to reduce emissions. The International Maritime Organization (IMO) has introduced measures such as the Energy Efficiency Ship Index (EEXI) and the Carbon Intensity Indicator (CII) to assess and improve the energy efficiency of ships. However, the cruise industry is advocating for metrics that consider their unique operational challenges, emphasizing the need for fair and accurate assessments.

As the cruise industry continues to grow, finding a balance between providing luxurious experiences for passengers and minimizing environmental impacts remains a critical challenge. The focus on sustainability and the development of cleaner technologies will be key in ensuring that the cruise industry evolves responsibly in the face of climate change concerns.