Who doesn't love a vacation? We all enjoy taking a break from work stress, traveling to remote places, and enjoying beautiful scenery. However, do we know how much our travels contribute to CO2 emissions and greenhouse gas footprint on our planet? To be honest, I wasn't sure of the figures off the top of my mind. Therefore, I decided to do some research and share my analysis here. I will be starting a series called "CO2 Emission Analysis for Travel," which will cover topics such as lodging, flights, and car transportation.
In this post, I will be covering the first topic in my CO2 Emission Analysis for Travel series: lodging (profile). Specifically, I sought to answer the question: how much CO2 is emitted when you book a hotel room?
To begin, I researched the ESG or sustainability reports 1, 2, 3, 4 of each brand in FY ‘21, and extracted their figures on the scope 1, 2, & 310 carbon emissions. I also collected their annual revenues in FY '21, and made the assumption that the carbon emissions were evenly distributed through every revenue dollar. Next, I selected $200 as a typical rate for a hotel room, recognizing that rates vary based on many factors such as location, amenities, and season. Using this rate, I derived the carbon emission amount corresponding to $200 in revenue.
Additionally, my research on US hotels and buildings led me to assume that a typical hotel room measures 325 square feet 7 and has a height of 14 feet 8. I used these measurements to calculate a typical space volume for a hotel room.
To quantify the amount of space that would be occupied by the emitted carbon dioxide if it were collected in the same hotel room, I developed a metric called "room space occupation by carbon emission" (RSOCE).

Learning from the infographic above, we can compare the relative performance of carbon emission management across multiple hotel chain groups. Hyatt (profile, shop) leads the way with a low RSOCE of 59%. Marriott is right behind with 64%, and Hilton is trailing the 3rd place with 86%. The 4th place belongs to IHG, but it's RSOCE is way higher than all the rest, astonishingly at 220%. It'll be interesting to dig further and reveal the reasons behind the scene for the performance variations. If anyone has the interest or the expertise for that research, please reach out and let's cooperate.
Keep in mind that a concentration of barely 10% carbon dioxide 9 may cause humans convulsions, coma, and death! Coexisting with the carbon emission in the hotel rooms could get us killed 5 times, 6 times, 8 times, and 22 times, when we booked the room at Hyatt, Marriott, Hilton, and IHG respectively. Fortunately, we do not have to coexist with the emitted carbon dioxide in these rooms as it is released into the open air.
However, as responsible individuals, we must acknowledge our impact on our planet and take action to minimize it. We strongly encourage everyone to step up and influence these hotel groups to further commit to sustainability and invest in decarbonization. This is the mission of our ResponsiBee platform, and we welcome your feedback and collaboration.
We would also like to acknowledge and give credit to the hotel brands mentioned above for taking a good start on sustainability and transparency. We had to exclude some other major brands from this analysis as their data collection is lagging behind, and there was not enough useful data to compare them.
​FY '21 (MTons) | ​Hilton | Wyndham | Airbnb |
# hotels | 7,000 | 9,000 | N/A |
# hotel rooms | 1,070,000 | 836,000 | 5,600,000 |
Scope 1 emission | ​415,034 | 53,122 | 807 |
Scope 2 emission | ​1,778,303 | 174,654 | 0 |
Scope 3 emission | 4,168,146 | 1,185 | 255,674 |
One example is Wyndham. Its ESG reports 5 briefly listed its scope 3 carbon emission as little as 1,186 metric tons in 2021, while its scope 1 emission is 53,122 metric tons and scope 2 emission is 174,654 metric tons in 2021. It is not uncommon for companies to have challenges with data collection and reporting, especially for emissions that fall under scope 3. Wyndham's low scope 3 emissions figure could be due to several factors, such as limited data availability, incomplete data collection, or lower reliance on suppliers for their operations. However, it is important for companies to improve their data collection processes to accurately measure their impact on the environment and set meaningful sustainability goals.

Another example is Airbnb. Arguably, Airbnb is the largest brand in the lodging industry. There are 5.6 million active listings on Airbnb worldwide, which is more than all the hotel rooms of Marriott, Hilton, Hyatt, IHG, and Wyndham combined. But its scope 3 emission 6 is counted as only 6% of Hilton’s, which is not comparable to be part of this analysis.

It's important to note that while Airbnb may have a smaller scope 3 emission compared to traditional hotel chains, it still contributes to the overall carbon footprint of the travel industry. As a platform that allows individuals to rent out their homes and apartments to travelers, Airbnb's impact on the environment is indirect but still significant. However, as Airbnb continues to grow and disrupt the lodging industry, it is important for them to also prioritize sustainability and transparent reporting on their carbon emissions.
References
1. 2021 Serve 360 Report. Environmental, Social, and Governance Progress at Marriott International. (link)
2. Hilton 2021 ESG Report. (link)
3. World of Care, Hyatt, 2021 Environmental, Social, and Governance Highlights. (link)
4. IHG Hotels & Resorts. 2021 Environmental, Social, and Governance Databook. (link)
5. Wyndham Hotels & Resorts. 2021 ESG Report (link)
6. An update on Environmental, Social, and Governance (ESG) at Airbnb, Sep 2022 (link)
7. Typical hotel room size in the US (square feet). (link)
8. Typical building story height (feet). (link)
9. Deadly CO2 concentration. (link)
10. Scope 1, 2 & 3 greenhouse gas emission. (link)