There are many important steps to take when traveling by plane, from packing a pair of compression socks to ensuring your passport is up to date if flying internationally. But there’s one important action item that many travelers overlook ― calculating your carbon emissions.

No matter how much you try to reduce the environmental footprint of your vacation or work trip, the fact remains that flying produces significant carbon dioxide emissions. According to the International Council on Clean Transportation, air travel accounts for about 3% of global carbon emissions, and the Environmental Protection Agency has estimated that flying produces 10% percent of all U.S. transportation-related emissions.

That’s why many airlines, booking platforms and third-party companies have started offering “carbon offsets” to help travelers neutralize their environmental impact. But these offerings have been criticized over their actual impact (or lack thereof), with some even calling them a “scam.”

Below, experts break down how carbon offsetting works, what you should know about its impact and other factors to keep in mind when it comes to your travel emissions.

“A carbon credit is a science-backed, third-party audited certificate that says that one ton of carbon pollution has been avoided or removed from the atmosphere,” Campbell Moore, managing director of carbon markets at The Nature Conservancy, told HuffPost. “‘Offsetting’ is the act of using the carbon credit. So, if I fly to a friend’s wedding across the country, and as a result one ton of carbon dioxide goes into the atmosphere, I would buy a carbon credit and use it to offset the one ton of carbon pollution I put in the atmosphere by flying.”

Basically, it’s presented as a way to compensate for the carbon dioxide emissions you produce by flying or through other activities by reducing an equivalent amount of carbon dioxide elsewhere.

“Some offsets use nature-based solutions ― like preserving or planting forests,” explained Jodi Manning, vice president of marketing and corporate partnerships at the carbon offset nonprofit Cool Effect. “Others use technological solutions, like carbon capture or replacing carbon-emitting energy sources with green technology.”

She noted that carbon offsetting has become increasingly popular in recent years, with Cool Effect’s first-quarter analysis this year showing a 186% year-over-year increase in travel offset purchases compared to 2022.

“Not all carbon credits are created equal,” Moore said. “The science on how to measure the carbon benefit of a carbon credit project is changing really rapidly. This is a good thing but means that some types of carbon credits are based on newer, stronger science than other types which are still catching up on the science.”

It’s not just individual travelers engaging with offset programs. Large companies and governments also play a big role in this practice’s growth, as the majority of Fortune 500 companies have made a public commitment to reducing their climate impact.

“A good corporate climate target focuses on reducing direct carbon pollution from the company’s business ― for example, by switching to EVs or renewable energy ― and then uses carbon offsetting to clean up remaining carbon pollution that is too expensive or technologically impossible to address in other ways,” Moore said. “Governments often use carbon offsetting as a policy tool as well because, when designed well, it can speed up overall climate progress and reduce the cost.”

Many companies tout their use of third-party organizations to verify their carbon offsetting projects and ensure the money is properly invested and impact correctly measured. There’s much talk of how these programs help expand clean energy infrastructure and save vulnerable ecosystems.

But a lot of climate experts have cast doubt on the effectiveness of these carbon offsets.

“The problem is ― can you be sure that what you’re paying for is really reducing emissions in the way that it says it is?” said Stephen Porder, a professor of ecology and evolutionary biology and associate provost for sustainability at Brown University. “You can’t be sure that a dollar spent on an offset is actually keeping CO2 out of the atmosphere. And there is no offset as good as not emitting that CO2 in the first place because there’s always some uncertainty or time lag or other issue associated with it.”

He offered the example of preventing deforestation. If someone is about to destroy an acre of forest but they’re suddenly offered money not to do it, they might accept the money in that moment and stop the process.

“But you don’t know if they come back next year and burn it down or go to another piece of land and burn that down,” Porder said. “You don’t know if your dollar really made an impact in the long term. Right now, it’s a voluntary market with very fluid rules. It’s not being regulated very well, and even where it is regulated very well, it’s hard to anticipate the problems that could come up.”

There are real concerns about whether carbon offsets actually capture or reduce emissions or ward off future emissions. The low cost of carbon offsets also gives experts pause.

“There’s no real agreed-upon price for this carbon,” Porder said. “Let’s say my wife and I want to fly from the East Coast to Paris for a vacation. I went online to various different carbon calculators, which tell me how much carbon I should pay for. But the offsets they’re offering me are $20-30 for that flight. That’s way less than the damage caused by the flight.”

Given the technological limits and lack of transparency about how many companies are actually using this money, Porder emphasized that carbon offsets can do more harm than good by “alleviating our guilty consciences” rather than actually reducing CO2.

“I could look at the menu of feel-good options, check a box and pay that money, and it might do some good things in the world depending on what I think is good for the world,” he explained. “But it’s not necessarily pulling the same amount of carbon out of the atmosphere that I’ve emitted by flying. I think there are individuals, corporations, universities and governments who use carbon offsets to trick themselves or others into thinking they’re cleaner than they actually are. But there are also others who use them in the hopes of doing good.”

Although the current market for carbon offsets leaves much to be desired, there have been many efforts to improve transparency and effectiveness that will no doubt continue into the future.

But in the meantime, there are better ways to reduce your environmental footprint as a traveler ― like by cutting down on unnecessary transportation emissions.

“I’ve really cut down on my flights and stopped flying across the country to give talks,” Porder said. “Young people in Europe have started to eschew flying and driving solo.”

Consider whether travel is really necessary in a given situation. For a work trip, ask if you can effectively conduct this meeting via Zoom instead ― or if you might be able to travel in a way that produces less carbon, like by taking the train instead of driving or flying.

“Travelers should always make a concerted effort to reduce the impact of their travel,” Manning said. “Avoid air travel when possible, but if you must fly, choose economy seats and opt for airlines that utilize biofuels.”

Indeed, your cabin class choice can impact your carbon footprint because business class seats take up more space and tend to reduce the occupancy rate of a plane.

“Travelers can also reduce the environmental footprint of their travel by packing lightly, selecting nonstop flights, and more,” Manning added.

Although purchasing carbon offsets might not truly mitigate the environmental damage of flying, you should still calculate your carbon emissions when you travel ― and then use that to take action in your own life.

“The first step is to become more aware of the issues and understand your impact as a traveler,” said Kaitlyn Brajcich, senior manager of communications and training at Sustainable Travel International. “Our online carbon footprint calculator offers an easy way for travelers to calculate the emissions from flights, vehicles, and boat travel. Our website also provides a wealth of information about the issues and tips for sustainable travel.”

There are plenty of calculator options online, including Conservation International’s Flight Carbon Calculator and BlueSkyModel’s, which breaks down the average emissions per mile flown.

“Once you’ve calculated the amount of carbon, you’ll want to charge or sort of ‘tax’ yourself a reasonable amount ― probably around $200-400 per ton,” Porder advised. “Then do something else in your own life with that money to reduce emissions. So if you drive a car, put it toward an electric vehicle. Or save it to replace your home’s insulation and invest in a better option for heating your home in the winter. Tax yourself and make an actual difference in your everyday emissions that you can feel sure about.”

If you don’t own a car or house, he suggested putting that money toward an organization doing something to help other houses reduce their energy use. He pointed to one of his students, who calculated how long she’d need to eat a vegan diet to make up for her summer vacation flight. (It was about six months.)

“The key to recognizing greenwashing is to ask if an organization or individual is fundamentally going after the sources of their own emissions, while perhaps also buying offsets as a short-term strategy and during that transition,” Porder said. “But if they’re just buying offsets in perpetuity and there’s no modification to how they emit in their personal lives, then they’re not taking it that seriously.”

If you’ve exhausted all your options for reducing emissions in your own life, you might be able to research and find a carbon offset program with enough third-party verifications and support from experts to feel comfortable handing over your money. But it might take time for such programs to develop into a strong option.

“We can’t let the perfect be the enemy of the good,” Porder said. “But we can’t let the bad in ― the things that give us the latitude to continue to emit where we’re emitting. That’s the worst-case scenario.”

Remember that the environmental footprint of the travel industry goes beyond individual travelers’ emissions as well.

“It’s great when people take responsibility for their carbon footprint,” Moore said. “But if we are going to save the world, it’s going to be because we change the big systems that matter ― government policy, corporate behavior, etc.”

He recommended contacting your elected representatives to say you want them to support low-carbon transportation policy, in addition to opting for low-emissions travel options in your life and finding ways to offset any carbon pollution that remains.

“Even a perfect carbon market will be just one tool in our climate toolkit and must only be used to address carbon pollution that remains after a government, company or individual has first taken ambitious action to reduce their carbon footprint,” Moore said. “There is much work to be done to improve every climate solution. We’re in a global crisis and inaction is not an option.”