2023 New York City Marathon Travel-Related Carbon Footprint Analysis

TLDR: Sardar Azimov, an avid marathon runner, explores the environmental impact of his running hobby, focusing on the 2023 New York City Marathon. He analyzes travel-related emissions, highlighting the significant carbon footprint of such events. The article emphasizes the challenge of estimating accurate emissions due to various calculation methods. It also notes the study’s limitation of excluding travel impact by non-participants. This suggests the need for more research in comprehensive environmental assessments of large-scale live events.

Running towards sustainability: Uncovering the environmental footprint of marathons

I’m not just an enthusiast of marathons; since 2016, I’ve completed 16 of them. My journey extends beyond achieving personal goals like completing the six World Marathon Majors.

Of the 16 marathons I have run, only five were local races. This led me to consider the environmental impact of my running hobby seriously. While my experiences have been enriching, my running-related travels made me acutely aware of the broader environmental implications, especially the significant carbon footprint associated with air travel.

This reflection led me to investigate the environmental impact of major sporting events. My curiosity about their ecological footprint inspired me to conduct an analysis, with expert support, focusing on one of the largest sporting events in the world. I chose the New York City Marathon, in which I participated in 2018, as a case study. The 2023 edition, being the largest event of the year, provided an ideal context for my research.

This study primarily focuses on estimating the environmental impact of the New York City Marathon, specifically in terms of participants' travel-related emissions. It does not delve into strategies for reducing these emissions. The emphasis is on raising awareness and providing data for reflection. Deciding how to reduce one’s carbon footprint, particularly in the context of participation in large-scale events like marathons, is presented as a personal choice. The article encourages readers to consider their impact and make informed decisions aligned with their values and environmental concerns.

The environmental footprint of marathon running

While the thrills and challenges of major marathons like the NYC Marathon captivate runners and spectators alike, these events also pose significant environmental challenges. Beyond the personal achievements and the communal excitement, there lies a lesser-discussed aspect of these events: their environmental impact.

The primary concerns echoed by various stakeholders, including local residents and environmental advocates, often center around the tangible aspects of running events — the waste generated during the race and the remnants left along the course. This visible impact, while critical, only represents a fraction of the broader environmental footprint of these marathons.

Despite commendable efforts to manage waste, as seen in the TCS Amsterdam Marathon’s implementation of waste-free areas and recycling hubs, and the London Marathon’s initiatives like on-demand bib printing and carbon levies for international participants, a more significant issue looms large — the impact of transportation, particularly air travel.

As highlighted in an Athletics Weekly article, despite proactive green initiatives, the overall environmental footprint of these events is heavily influenced by the emissions from participants’ travel. This is especially true for international marathons, where thousands of runners, along with their supporters, converge from around the globe, often by air. This mode of travel, essential for the international character of these events, paradoxically poses a substantial challenge to their environmental sustainability.

According to a study from a group of researchers published in the International Journal of Environmental Research and Public Health, almost 83% of the carbon footprint of marathon events is attributed to travel. This figure becomes particularly striking considering that 37% of participants in events like the New York Marathon are international travelers.

Intrigued by this substantial impact, I embarked on a project to quantify the overall carbon footprint of all 51,933 participants (with 51,402 finishers) in the 2023 NYC Marathon, aiming to share my findings with a wider audience and raise awareness about this critical issue.

Travel impact analysis of NYC marathon participants

In-depth examination of participant travel emissions: Methodology applied

In this section, we delve into the meticulous methodology adopted to analyze the travel emissions of 51,933 participants in the New York Marathon. The process encompasses a series of sophisticated steps, each designed to contribute to a comprehensive understanding of the environmental impact of this iconic event. From data collection to the final emission summation, each step is crucial in accurately representing the marathon’s carbon footprint. This detailed approach enhances our finding’s precision while having significant limitations.

1. Comprehensive Data Collection: The analysis commenced with the extraction of detailed participant data, encompassing 51,402 finishers (we don’t have the data on 531 runners who did not finish the race). This crucial first step laid the groundwork for an extensive environmental impact assessment.
2. Sophisticated Data Processing: Utilizing advanced algorithms like ngram and Levenstein, the data underwent a rigorous clustering process. This resulted in a meticulously cleaned database, streamlining the subsequent location matching.
3. Accurate Location Matching: Matching against a database of cities with populations over 500, the process identified 1,950 unique non-matched locations, while successfully matching 8,400. This differentiation was key to accurate distance calculation.
4. Precise Geolocation: The Haversine formula, augmented by tools like OpenStreetMaps, was employed to geolocate all data points, ensuring accurate distance measurements for each participant.
5. Detailed Distance Assessment: The study calculated the precise travel distance for each marathon participant, considering both their origin and destination.
6. Mode of Travel Analysis: In distinguishing between air and car travel, it was posited that distances less than 500 km were likely covered by car. A 30% increase was applied to these distances to account for additional travel.
7. Rigorous Carbon Footprint Calculation: The analysis utilized EPA data for car emissions and employed two distinct methodologies for flight-related CO2 — one from the Travel Impact Model used in Google Flights and another incorporating ADEME’s methodology, which includes contrail impacts and variable CO2/km for different flight lengths.
8. Comprehensive Emission Summation: The culmination of this process was the summation of all emissions, offering a comparative analysis of the two flight impact assessment methods.

Average CO2 emissions per km traveled used

Flight emissions

The absence of standardized methods for calculating flight emissions poses a significant challenge, particularly for individuals without a scientific background. The discrepancies between various methods lead to a wide range of estimates, complicating efforts to ascertain the real environmental impact of air travel accurately. This complexity underscores the need for unified and accessible approaches to emission calculations, facilitating better understanding and more effective decision-making regarding travel-related carbon footprints.

Two distinct models were employed in the analysis to emphasize the variance in emission calculations: one included the impact of contrails and the other excluded it. This approach was taken to illustrate how including or excluding certain factors, like contrails, can significantly alter the estimated carbon footprint of air travel.

A) With contrail

In the case of the calculations including carbon contrail impact, to further refine the travel impact analysis, specific CO2 emission factors were applied based on travel distance brackets. These factors, expressed as kilograms of CO2 per kilometer per traveler, are crucial in calculating the precise environmental impact for each distance range:

• Under 600 km: 0.3124 kg/km
• 600–1000 km: 0.275 kg/km
• 1000–2000 km: 0.2313 kg/km
• 2000–2600 km: 0.1967 kg/km
• Over 2600 km: 0.1715 kg/km

An advanced online tool was utilized to accurately determine CO2 emissions for various travel distances. This tool incorporated methodologies from the ADEME 2021 model, which notably includes the impact of contrails. The process involved uploading a list of 500 major airports globally and estimating the total environmental impact of traveling from each of these airports to New York. Analyzing the distances and corresponding CO2 emissions per kilometer, the study derived average values for each defined bracket, ensuring a nuanced and comprehensive assessment of the carbon footprint associated with different lengths of air travel.

B) Without contrail

In assessing flight emissions without the impact of contrails, the study utilized Google Flights’ online estimator. This method offers a public-facing view of flight-related carbon emissions. For those interested in the finer details of this calculation method, Google Flights provides technical specifications and methodologies on their GitHub repository, ensuring transparency and accessibility of their model.

While the Google Flights estimator provides a convenient tool for calculating flight-related emissions, it’s important to note that omitting the impact of contrails might lead to an underestimation of the actual carbon footprint. This could potentially mislead travelers about the true environmental impact of their flights, possibly reducing feelings of responsibility or remorse for their carbon emissions. Such an approach, while user-friendly, raises concerns about the accuracy of public-facing carbon footprint tools and their influence on traveler awareness and decision-making.

Car emissions

For car travel emissions, the analysis incorporated data from the EPA’s study on Greenhouse Gas Emissions from a Typical Passenger Vehicle. An average emission factor of 0.25 kg of CO2 per kilometer was used.

Data analysis and findings

The section below provides an overview of different analyses performed on the datasets gathered. The location data covers finishers with matched locations (51,327 runners).

1) Distribution of runners: per country, per state (for the US) and per city

Overview per country

In the New York City Marathon, the participant data, post-cleansing and clustering, reveals a compelling global distribution. The United States leads overwhelmingly with 67.62% of runners, underscoring the marathon’s popularity and accessibility within the country.

The top five countries following the U.S. are Italy (4.39%), France (3.43%), the United Kingdom (3.24%), and Germany (2.07%). These figures not only highlight Europe’s strong representation but also reflect the global appeal of the marathon. The presence of countries such as Mexico, Canada, and Australia further emphasizes its international allure.

Collectively, the top 20 countries account for 94.5% of all participants. This concentration indicates distinct geographical trends in marathon participation and points to the New York City Marathon as a truly international event, attracting runners from across various continents. This global participation also plays a crucial role in considerations of the event’s environmental impact, especially regarding travel-related carbon emissions.

Overview per US state

In the New York City Marathon, participants from the United States show a concentrated distribution across states. New York State leads with 53.85% of U.S. runners. Following are New Jersey (9.96%), California (4.51%), Massachusetts (3.29%), and Florida (2.92%). Texas, Connecticut, Illinois, Pennsylvania, and Colorado also feature in the top ten, with percentages ranging from 1.32% to 2.68%. Collectively, these top ten states represent 84.8% of the U.S. participants in the marathon.

Overview per city

The distribution of marathon participants by cities complements the earlier analysis of countries and states. Dominating the city list is New York City, with 8,835 runners, aligning with the state of New York being the most represented in the U.S. participation. This is further supported by the presence of other New York cities like Brooklyn (3,257), Bronx (482), Astoria (378), Long Island City (320), and Staten Island (269).

Chicago (416), Jersey City (374), Boston (266), Washington (208), San Francisco (204), Hoboken (246), Denver (172), and Flushing (156) represent other U.S. cities, correlating with the earlier observation of significant participation from states like New Jersey, Massachusetts, Illinois, California, and Colorado.

Internationally, London (346) and Paris (240) are the most represented, consistent with the United Kingdom and France being among the top countries. Additionally, cities like Ciudad De México (190), Milano (169), Roma (158), and Madrid (155) align with the noted participation from Mexico, Italy, and Spain.

This city-wise data underscores the geographic diversity of the participants and mirrors the broader distribution trends observed at the country and state levels.

2) Total CO2 emissions

a. Global CO2 for all participants

In an analysis of the environmental impact of the New York City Marathon, a striking figure has emerged: the event’s total CO2 emissions, including the often overlooked contrail impact, amount to 54.3 kilotonnes. By extrapolating the data to the total number of participants, we can safely presume that the total emissions are closer to 54.94 kilotonnes (by applying the average emissions to all 51,933 participants).

This far exceeds the emission estimates from models that exclude contrails, such as Google’s travel model, which accounts for a mere 34.6% of this total. Such a discrepancy underscores the necessity of a comprehensive approach to calculating the carbon footprint of major events.

The methodology behind this analysis considered travel distances, distinguishing between participants traveling less than 500km — assumed to arrive by car at an emission rate of 0.25 kg of CO2 per km — and those who traveled further distances, likely by plane. This distinction is crucial, as air travel, especially international, has a significantly higher carbon footprint per individual, exacerbated by the high-altitude contrail effects that are often omitted from standard emission calculations.

In the environmental analysis of the New York City Marathon, the mode of transport chosen by participants is a crucial factor. Among the participants, 25,522 traveled by car, generating approximately 3.72 kilotonnes of CO2, which constitutes 6.85% of the overall emissions when including the impact of contrails. On the other hand, air travel, chosen by 25,805 participants, resulted in about 50.57 kilotonnes of CO2, accounting for a substantial 93.15% of the total emissions. This disparity underscores the disproportionate impact of air travel on the event’s carbon footprint.

Additional emissions from accompanying travelers

Important Clarification: This study’s emission calculations focused solely on the marathon participants. However, it’s worth noting that many runners are likely accompanied by friends or family members. If we conservatively estimate that 50% of runners had at least one additional person traveling with them, this could result in an extra 26 kilotonnes of CO2 emissions, for a total of 76.75 kilotonnes of CO2. This factor underscores a potential underestimation in the overall environmental impact of the marathon.

Comparing with other emissions

When comparing the marathon’s emissions to the annual carbon footprint of individuals from various regions, the findings are startling:

• For Europe, with an average of 6.4 tonnes of CO2 per person per year, it would take approximately 8,484 individuals to equal the marathon’s emissions.
• In North America, where the average is 16 tonnes of CO2 per person per year, around 3,394 individuals would account for the same emissions.
• Globally, with an average of 4.8 tonnes of CO2 per person per year, the emissions equate to the annual footprint of roughly 11,313 individuals.

This comparison casts a new light on the environmental cost of such events and acts as a call to action for incorporating sustainable practices and effective carbon offsetting measures.

For perspective, offsetting the marathon’s carbon footprint would require an annual absorption capacity of approximately 2.17 million trees. This estimate is based on the average CO2 capture of 25kg per tree per year, a natural contribution highlighting the magnitude of the event’s emissions.

Assuming a normal spacing for new planting of native mixed woodland is around 1,600 trees per hectare, it would require approximately 1,356 hectares to plant 2.17 million trees. This area is equivalent to about 1,233 Olympic-size fields (13.56 square kilometers or around 5.24 square miles). This highlights the land scale necessary for large-scale tree planting efforts to mitigate environmental impacts.

The New York City Marathon’s carbon analysis serves as a case study in the environmental impact of global sporting events, offering valuable insights into the balance between cultural and athletic celebration and ecological responsibility.

b. Emission per country (% of total CO2 emissions, average CO2 emissions per runner, performance global average vs country average)

The provided table offers an insightful look into the carbon footprint of the New York City Marathon participants by country. Here are the key takeaways from the data:

• United States Emissions: The U.S. accounts for the largest number of runners (67.6%) but a lower percentage of total emissions (22.63%), suggesting shorter travel distances for the majority of participants.
• High Emissions per Runner for European Countries: Italy, France, and Germany have significantly higher emissions per runner compared to the global average, with Italy’s emissions per runner at 245.1% of the global average. This is indicative of the greater distances traveled and potentially reflects a larger carbon footprint per participant due to long-haul flights.
• Significant Contributors to CO2: Despite having fewer runners, Italy (10.76%), France (7.55%), the United Kingdom (6.58%), and Germany (6.54%) contribute substantially to the total emissions due to the longer distances traveled from Europe to the U.S.
• Ratio of Global vs. Country Average: Countries further from the U.S. have a higher ratio compared to the global average CO2 emissions per runner, reflecting the impact of distance on carbon emissions.
• Carbon Intensity of Travel: The average CO2 emissions per runner for countries like China and Japan are among the highest, exceeding the global average by over 290%. This underscores the significant carbon intensity associated with transcontinental travel.

This analysis highlights the environmental impact of international participants traveling to the New York City Marathon and emphasizes the importance of considering sustainability in such events. Strategies to offset carbon emissions could include encouraging local participation, providing incentives for carbon offsetting, or supporting sustainable travel options.

c. Emission per US state (% of total CO2 emissions, average CO2 emissions per runner, average country vs average state)

Analyzing the carbon emissions of New York City Marathon participants at the state level, we find that the top 10 states account for 75.2% of all U.S. emissions associated with the event. New York, as the host state, while boasting the largest number of runners, presents a lower emission per runner, indicative of local participation and shorter travel distances.

In sharp contrast, California, with fewer participants, contributes a disproportionately high 19.07% of the U.S. total CO2 emissions. Runners from California have a CO2 emission per runner of 1,504 kg, far exceeding the national average due to the necessity of long-haul flights to the East Coast.

Texas and Florida follow suit, with their runners’ emissions surpassing 7% of the U.S. total, reflecting the environmental impact of significant interstate distances covered, likely through a combination of car and plane travel.

Notably, states like Washington and Colorado, despite having smaller contingents of participants, show high emissions per runner. This pattern points to the considerable carbon footprint of cross-country flights from these states.

New Jersey, geographically close to New York, illustrates the environmental benefits of proximity, with its runners averaging a low 100 kg CO2 per runner, reinforcing the influence of travel distance on emissions.

This state-level emission analysis mirrors the findings of country-level emissions, where distance significantly affects the carbon footprint. Similar to how European countries like Italy and France have higher emissions per runner due to the distance traveled, states like California and Texas show the same trend within the U.S.

Collectively, these insights into the state and country-level emissions of New York City Marathon participants highlight the considerable environmental impact of long-distance travel, whether by air or car. They emphasize the need for event organizers to consider and encourage sustainable travel options and for participants to be conscious of their travel choices in reducing their carbon footprint.

Broadening the Perspective: Global Emissions Across Different Sectors

While air travel, responsible for about 2.5% of global CO₂ emissions, is often a focal point in climate discussions, its overall contribution to climate change is higher, accounting for approximately 3.5% of effective radiative forcing. This difference is mainly due to non-CO₂ climate impacts, such as contrails, which are significant contributors to global warming.

However, it’s important to contextualize aviation’s role within the broader spectrum of global greenhouse gas emissions. Other major sectors contribute significantly to the global carbon footprint:

• Energy Use in Buildings: Accounts for 17.5% of emissions, split between residential (10.9%) and commercial buildings (6.6%).
• Fugitive Emissions from Energy Production: Contribute 5.8%, with oil and gas (3.9%) and coal (1.9%) as primary sources.
• Agriculture and Fishing Energy Use: Represent 1.7% of emissions.
• Direct Industrial Processes: Cement production (3%) and chemicals & petrochemicals (2.2%) contribute significantly.
• Waste: Wastewater (1.3%) and landfills (1.9%) together account for 3.2% of emissions.
• Agriculture, Forestry, and Land Use: This sector is responsible for 18.4% of emissions, with significant contributions from various subcategories like deforestation (2.2%), crop burning (3.5%), rice cultivation (1.3%), and agricultural soils (4.1%)​​​​​​​​.
• Livestock & Manure: Emit 5.8% of greenhouse gases, primarily from enteric fermentation in ruminants and the decomposition of animal manures​.

Understanding the relative contributions of different sectors is crucial for developing effective strategies to address climate change. While individual actions, like choosing local marathons over international ones, are important, systemic changes across various sectors are vital to significantly reducing global greenhouse gas emissions.

Conclusion

My transition from a marathon enthusiast to an environmental advocate highlights an important message for the running community and event organizers. The environmental impact of marathons is not confined to the realms of waste management at events. A significant part of this impact is attributable to transportation emissions, especially air travel, which accounts for about 2.5% of global CO2 emissions.

This broader outlook necessitates a paradigm shift in our approach. Tackling the environmental impact of marathons requires a holistic strategy that transcends local event management and embraces global changes across all sectors. While individual actions, such as opting for local events and leveraging innovative carbon offset technologies, are valuable, they are just pieces of a larger puzzle. Substantial change hinges on systemic transformations across various sectors, including energy, industry, agriculture, and waste management, to meaningfully reduce global greenhouse gas emissions.

The New York City Marathon, with its estimated 54.3 kilotons of CO2 emissions, provides a stark perspective when compared to global flight emissions. It represents about 0.0059% of the total CO2 emissions from global flights. This comparison underscores the importance of addressing air travel emissions in the context of larger environmental efforts.

This in-depth analysis of marathon-related emissions mirrors the greater challenges in mitigating climate change. It calls for action not only from the running community but also from global citizens and policymakers. A conscientious approach to our carbon footprint in all life aspects is imperative, coupled with supporting broader changes that pave the way for a sustainable and environmentally conscious world.

Individual efforts are crucial, but they must be part of a more expansive, global strategy aimed at achieving significant reductions in greenhouse gas emissions across all sectors. Collective action and systemic change are vital to effectively tackle the pressing issue of climate change.