When a tourist flies into Honolulu from the West Coast, that one trip might not seem like a massive environmental problem. In terms of carbon emissions, it’s the equivalent of driving 710 miles — about the distance from L.A. to San Francisco and back.

But the cumulative impact of tourists flying to and from Hawaii is enormous.

Take the 3.8 million visitors in 2017 from just the western U.S., Hawaii’s biggest tourist market. The carbon footprint of their round trip air travel is roughly like driving a car around the equator — 225,000 times.

That’s according to estimates made by Civil Beat using carbon calculators from a  United Nations aviation agency and the federal Environmental Protection Agency, as well as travel data from the Hawaii Tourism Authority.

While the millions of tons of carbon produced by flights to Hawaii may be invisible, it’s having a profound effect on the environment.

“The carbon footprint of aviation overall is one of our biggest — and dirtiest — climate secrets,” said Jeff Mikulina, executive director of the Blue Planet Foundation, which advocates for using clean energy.

The reasons are obvious. It takes an enormous amount of energy to propel a passenger airplane through the sky at 35,000 feet.

“The aviation industry is really carbon intensive, and with good reason,” said Josh Stanbro, executive director of Honolulu’s Office of Climate Change, Sustainability and Resiliency. “There are a lot of things we can electrify. But as of yet, air transportation isn’t one of them.”

Flights to and from Hawaii from the western U.S. produced 2.3 million tons of carbon in 2017. Flights to and from Hawaii from all over the world, produced approximately 6.3 million tons, according to the analysis. (An explanation of Civil Beat’s methodology is at the bottom of the story.)

That’s the equivalent of the CO2 produced by generating electricity for almost 1.1 million homes in a year, according to the EPA.

To capture that much carbon annually would take about 7.4 million acres of forest, more than the total 4.1 million acres of land in the Hawaiian islands.

Although only an estimate, it’s a stunning amount of CO2. But it’s not surprising given Hawaii’s remoteness and popularity as a tourist destination.

And it poses a conundrum for the state.

An industry that is the lifeblood of the economy also has enormous negative environmental impacts. It’s a problem too often ignored, said Mikulina.

Policymakers, the public and tourism executives have begun talking more openly about how to manage Hawaii’s roughly 10 million annual tourists rather than how to attract more of them.

But much of the discussion focuses on highly visible side effects: crowded beaches and hiking trails, damaged reefs, residential neighborhoods overrun with vacation rentals and the like.

The carbon footprint of aviation overall isn’t given the same amount of attention, Mikulina said.

“People seem unwilling to discuss it or fully disclose it because jet travel is an inescapable part of living on and visiting these islands,” he said. “It would serve our overall state climate goals if we could have more transparency and discussion about the huge carbon footprint of jet travel.”

Growing Interest In The Issue

There are hints that things may be starting to change.

In July, Honolulu City Councilwoman Kymberly Pine introduced a bill requiring Stanbro’s office to track the Oahu visitor industry’s efforts to promote sustainable tourism, including efforts related to transportation.

“It just seems that we have forgotten to target a lot of our policies to ensure a high quality of life for our residents,” Pine said during a hearing discussing the measure. “Having 10 million tourists in Hawaii — I never thought we’d reach that point.”

Globally, an increasing focus is on the aviation industry’s role in managing the environmental effects of tourism.

According to the International Air Transportation Association, an international trade group that represents 290 carriers, domestic and international flights in 2018 emitted around 895 million metric tons of carbon dioxide in 2018.

That was a 26% increase over 2013, when flights accounted for 710 million tons.

Concerns over such emissions are a big enough deal in Europe that there’s now a word, “flygskam,” to describe the practice of calling people out for globetrotting on carbon-emitting passenger jets, The Washington Post reports. Flygskam is Swedish for “flight shame.”

Among those flight-shamed recently is Prince Harry of Wales and his wife Meghan Markle, who have been criticized for taking private flights with a bigger carbon footprint than commercial ones.

Whether the flight shame movement catches on in Hawaii and the rest of the U.S. remains to be seen, but the airline industry is taking note. Flygskam was a major agenda item at a three-day airline summit in Seoul in June, according to Reuters, which reported, “Airlines scramble to overcome polluter stigma as ‘flight shame’ movement grows.”

“Unchallenged, this sentiment will grow and spread,” Alexandre de Juniac, the head of the International Air Transport Association, told some 150 CEOs at the summit.

The industry is responding in part by emphasizing the economic benefits air travel provides.

Nancy Young, the vice president for environmental affairs for the trade association that represents U.S. carriers, Airlines for America, declined to be interviewed on the record for this article.

But Carter Yang, an Airlines for America spokesman, provided a statement saying the industry supports “more than 10 million U.S. jobs and $1.5 trillion in annual U.S. economic activity.”

Yang also said the industry contributes “just 2 percent of the nation’s greenhouse gas emissions.”

For Hawaii, the percentage appears to be much higher than that. A 2019 report by Honolulu’s sustainability office estimated aviation accounted for 13% of Oahu’s carbon emissions.

The Elemental Excelerator, a business development organization that works with innovative renewable energy and transportation companies, among others, estimates the percentage at more than 20%.

In addition, Hawaii’s aviation industry outpaces all other sectors in its petroleum use.

The industry gobbled up 30.2% of the petroleum used in Hawaii in 2017, the State Energy Office reported in July using the most recent available data. That compared to 28.4% for ground transportation and 24.5%  for electric power.

In raw numbers, the amount of carbon dioxide produced is massive.

Using fuel data from the federal Energy Information Administration, the Honolulu sustainability office pegs the amount of carbon produced by the aviation industry for Oahu alone to be about 1.88 million tons annually. However, the office only looked at domestic fights, and accounted only for the outbound leg, said Rocky Mould, energy program manager for the sustainability office.

In an attempt to estimate the carbon footprint of flying millions of tourists to and from Hawaii, Civil Beat used a more expansive scope, looking at round-trip flights from everywhere.

Considering the broader scope of Civil Beat’s analysis, Mould said, “The number seems pretty good, I have to say.”

Carbon Neutral Growth By 2021?

The airlines are taking the issue seriously.

Hawaiian Airlines is a case in point. The carrier has invested in a new fleet of fuel efficient Airbus A321 neos, which it says emit 16% less carbon than previous generation planes. The carrier also is reducing its use of jet fuel to power aircraft waiting at the gate by using more efficient external electricity instead of power generated by the airplane.

Hawaiian estimates this could save approximately 620,000 gallons of fuel annually and cut CO2 emissions by 5,933 metric tons. That’s roughly enough fuel to fly the airline’s wide-body fleet for a day, the airline says.

In another initiative, United Airlines allows travelers to buy carbon credits to offset the impact of flights. To neutralize a roundtrip flight between Los Angeles and Honolulu costs $6.30. The money goes to help preserve forests around the world in partnership with Conservation International, an environmental organization.

Internationally, the United Nations International Civil Aviation Organization is promoting a plan to cap the growth of aviation carbon emissions starting in 2021. Known as the Carbon Offsetting and Reduction Scheme for International Aviation, or Corsia, the plan has received support from the world’s major carriers, including the U.S. industry.

Locally, Hawaiian Airlines is working in a consortium with other Hawaii companies and the Nature Conservancy to determine whether a carbon offset market can be developed in Hawaii, said Ann Botticelli, a Hawaiian spokeswoman.

Known as the Hawaii Green Growth Sustainability Business Forum, the group’s members include major companies such as Hawaiian Electric Industries, Hawaii Gas and Alexander & Baldwin, Botticelli said in an email. The project is in its pilot stage but is “an exciting idea,” she said.

The Elemental Excelerator is also seeking to develop market-based solutions to carbon emissions by helping finance and advise promising companies that can help solve the problem.

One of these companies, Ampaire, has begun testing a small electric airplane that can be used for short flights within the islands. The plan is to begin testing flights between Kahului to Hana, Maui, around the beginning of 2020 in partnership with Mokulele Airlines, said Aki Marceau, the Elemental Excelerator’s managing director for policy and community.

Another company, called Signol, is taking a completely different approach, building on a case study of a Virgin Airlines project published in the Harvard Business Review.

The conclusion is that getting pilots to make small changes in the way they operate aircraft can have a big impact on reducing fuel use and carbon emissions. Signol describes its tool, which can nudge pilots to be more efficient, as “Fitbit for work.”

How much difference all of this will make remains to be seen, given the growing hordes of tourists.

“Efficiency has gotten better,” Stanbro said. “But the number of tourists is going up.”

How We Calculated Air Travel’s Carbon Footprint

Civil Beat used the latest annual visitor data from the Hawaii Tourism Authority along with carbon emissions calculators created by the United Nations’ aviation organization and the U.S. Environmental Protection Agency to estimate the carbon footprint of visitors flying to and from Hawaii.

Civil Beat consulted a number of tourism and climate change experts, including the United Nations International Civil Aviation Organization, before devising the following methodology to estimate the carbon footprint of tourists traveling to and from Hawaii.

Civil Beat first calculated the number of visitors to Hawaii by region based on HTA data from 2017, the most recent year annual data was available. Civil Beat next selected an airport in each of these regions to use as a benchmark. For example, the vast majority of air travelers from the Western U.S. Region come from California, so Civil Beat used LAX as the benchmark airport for that region.

To calculate the carbon footprint for each region, Civil Beat put the number of visitors into the ICAO’s carbon calculator using HNL and the corresponding region’s benchmark airport. Civil Beat repeated the procedure for the eight market regions identified by HTA.