Two environmental groups staged a protest in Seattle alleging that Carnival runs a fleet of "dirty ships" because of the use of heavy fuel oils.
But the company says the protesters are targeting a company that is already at the forefront of environmental stewardship.
Stand.earth and Seattle 350 activists were dressed as polar bears and dolphins as they demonstrated at Seattle's cruiseship terminal to urge the Miami cruise giant clean up its act.
Reduce HFO
The groups have been campaigning against New York-listed Carnival in a bid to persuade the world's largest owner of cruise ships to reduce greenhouse gas emissions and its use of HFO.
Sean Rudolph, Stand.earth's corporate climate campaign director, tells TradeWinds that the organisations want Carnival to lead the shipping and cruise industries in playing a role in fulfilling the goals of the Paris Climate Agreement.
"I think that Carnival is in the best position to realize this kind of vision for the cruise industry and shipping industry moving forward," he said.
Stand.earth and Seattle 350 say that Carnival has increased its climate pollution by 20% over the past decade, producing 2,111 pounds of carbon dioxide per passenger per trip in 2015. That's the equivalent emissions of driving a car 2,295 miles, which is most of the way across the US.
Carnival spokeswoman Jennifer De La Cruz said Stand.earth's statements are "inaccurate and highly misguided".
The company is an environmental leader in the cruise industry, having spent $400m on exhaust gas cleaning technology known as scrubbers in addition to ordering the first LNG-fuelled cruiseship.
"As the world’s largest cruise operator, our success is dependent upon the health of our environment and the world’s oceans," she told TradeWinds. "Carnival Corp has and continues to invest hundreds of millions of dollars in technology to mitigate our environmental footprint and conserve energy.
