Watch out U.S. airlines, the flight shaming movement is likely on its way to America.

That’s what the head of New York-based airline JetBlue told investors during the company’s fourth-quarter earnings call—the latest sign the aviation industry sees climate change as a growing threat to its business.

“This issue presents a clear and present danger if we don’t get on top of it,” JetBlue CEO Robin Hayes said on the call late last month. “We’ve seen that in other geographies, and we should not assume those sentiments won’t come to the U.S.”

n January, JetBlue became the first major U.S. airline to announce plans to become carbon neutral as a way to assuage customer concerns over the impact of commercial flying on the climate. In a press release, the airline said it hopes by July to offset greenhouse gas emissions from all of its domestic flights by funding projects that help reduce emissions elsewhere.

The very notion of “green” flights strikes some climate activists as absurd. Peter Kalmus, a climate scientist at NASA’s Jet Propulsion Lab and “low-carbon travel” activist, said there’s no more potent way hour-for-hour to warm the planet than flying. He considers offset schemes suspect, and he believes offsets might do more harm than good because they make people believe they can fly without contributing to climate change. Kalmus notes that he speaks only on his own behalf, not NASA’s.

But Peter Miller of the Natural Resources Defense Council told InsideClimate News that the offset market has made major strides toward becoming more standardized, transparent and effective.

Commercial aviation is responsible for 2.4 percent of the world’s greenhouse gas emissions and could account for up to a quarter of the world’s carbon budget by 2050, according to a 2019 study by the International Council on Clean Transportation.

JetBlue’s move follows those of a handful of European airlines—EasyJet, British Airways and Air France—that have made similar pledges to offset either domestic or regional flights through carbon offset schemes.

Carbon offsets allow individuals, companies or governments to essentially balance their greenhouse gas emissions by investing, for example, in efforts to plant trees or develop renewable energy to replace fossil fuels.

JetBlue said it will pay to offset roughly 8 million metric tons of carbon emissions that its domestic flights produce each year by investing in projects that include forest conservation efforts, landfill gas capture, as well as solar and wind power development.

JetBlue wouldn’t disclose the cost of its plan. But Sophia Mendelsohn, JetBlue’s head of sustainability and environmental social governance, said the airline isn’t passing the cost along to customers, noting that it’s “the cost of doing business” today.

Carbon offsetting is set to become a multi-billion dollar business over the next five years, reaching at least $6.2 billion a year for air travel alone, according to an analysis by Citigroup. That cost will be absorbed by the airlines or have to be passed along to the customers, Mark Manduca, who led the analysis, said in an interview.

A decade ago, the International Air Transport Association (IATA) set a number of ambitious targets to combat the industry’s contributions to climate change. They include an agreement that binds the group’s hundreds of member airlines, including JetBlue, to participation in offset schemes starting in 2027. In that sense, JetBlue is getting a head start in familiarizing itself with the carbon offset market, Mendelsohn said

But despite early pledges from JetBlue and other airlines to decarbonize, offset schemes—and carbon markets in general—have drawn criticism from Kalmus and other scientists, who say that offsets encourage industries and governments to continue polluting rather than cutting emissions. The critics also say such measures incentivize slower progress toward the kind of low-carbon economy needed to avoid climate catastrophe.

“Offsetting is worse than doing nothing,” wrote Kevin Anderson, a leading climate researcher, in the journal Nature. “It is without scientific legitimacy, is dangerously misleading and almost certainly contributes to a net increase in the absolute rate of global emissions growth.”

Offset schemes also lack consistent regulation internationally, Citigroup’s Manduca said. “Who’s actually regulating all this stuff? Water projects in Uganda. You have solar panels in India. You’ve got forest projects in South America. It feels very fragmented,” he said. This makes it difficult in many cases to know whether money for offsets is in fact going toward carbon reduction, or even how those reductions are being measured.

But many in the aviation industry see offsetting as a necessary step to reducing emissions as airline travel continues to grow—and they don’t have many other options.

Airline travel is also expected to double in the next 20 years, according to IATA estimates. And that growth will be particularly high in emerging markets like India and China.

Lower- or zero-emission planes, such as hybrids or electric, won’t come into play until the mid-2030s, said Chris Goater, IATA’s manager of corporate communications, and then only for shorter hauls. Until then, offsets are needed to close the gap between increasing flight numbers and emissions from current plane models, he said.

Peter Miller, who helps direct the Natural Resources Defense Council’s climate and clean energy program, said organizations like Climate Action Reserve, a voluntary offset registry for which Miller is a board member, help add transparency to the offset process. Climate Action Reserve keeps track of projects while ensuring they provide “credible, quantitative, validated, verified emission reductions,” he said.

“What has been established are these protocols that say, ‘If you want to do an afforestation project, this is what you have to do. This is how you will calculate carbon emissions. And this is how you will report and verify those emission reductions,’” Miller said. “That gives a lot more credibility and accuracy to the overall project and avoids the problem where everybody is counting things differently.”

Still, many still see refraining from flying as the better option. The flight shaming movement that started in Sweden in 2017 and gained worldwide attention with teenage climate activist Greta Thunberg’s refusal to fly to the UN climate summit last year, has arguably put a dent in air travel for some European countries. (The Swedish word flygskam, which was associated with a rail trip she took across Europe last year, translates as “flight shame.”)

Sweden saw a 4 percent drop in overall flights in and out of the country in 2019, according to an annual report released by the country’s state-run airport operator, Swedavia. Germany is also expected to see a drop in the number of flights by 2.9 percent this year.

But the movement has also spread beyond Europe, including to the U.S. and China.

The European Investment Bank released a survey earlier this year that showed most U.S., Chinese and European citizens are planning to fly less over the holidays in 2020 as a way to reduce carbon emissions and slow global warming. Nearly 70 percent of U.S. respondents said they would fly less this year to help mitigate climate change, the poll found. For China, the numbers were even higher at 94 percent, and in Europe 75 percent.

More than 23,000 people have signed a pledge online to not fly this year. The website, called We Stay On The Ground, began in Sweden. Today, it runs independent operations in the U.S., Canada, Peru and Australia, among others, according to the site.

Kalmus, the NASA climate scientist, said he hasn’t flown since 2012. As an academic, he said in an interview, avoiding flying has made attending conferences related to his work or even visiting family in other states very difficult, but that in the end, it’s worth it to help fight climate change.

Three years ago, Kalmus drove three days from his home in Los Angeles to attend an academic conference in Maine. “It was the first time I drove all the way from the West Coast to the East Coast and back,” he said.

In 2017, he launched his own website to promote the idea of not flying, or even flying less, and the site has since gathered nearly 600 people pledging to do so. Most of those pledges have come from either the U.K. or the U.S.

Like Anderson, another climate scientist, Kalmus doesn’t trust carbon offset schemes, saying that flying less or refraining from flying is a better option. And he expects more people will join the cause in years to come.

“Just five years ago, you weren’t seeing the massive wildfires in California and Australia you’re seeing now. Or the massive flooding in the Midwest,” he said. “That’s not going away—it’s only going to get worse. So, this movement isn’t going away either.”