By: Emmanuel Mayani
Picture a towering ‘carbon skyline,’ growing taller as each car on the road adds another layer of emissions. With over a billion vehicles worldwide, every mile traveled builds this skyline higher, making transportation a leading driver of the climate crisis.
Preliminary data from NASA indicates that 2024 was the hottest year on record, highlighting that global warming is neither distant nor abstract; it displaces communities, disrupts ecosystems, and threatens public health. The 2015 Paris Agreement called for limiting warming to “well below” 2°C. Still, transportation emissions have surged nearly 80 percent since 1990, significantly contributing to global warming and making it one of the most challenging and vital sectors to decarbonize.
Addressing this crisis requires both systemic change and individual action. As individuals, we have a leading role in overcoming this problem.
Nationally Determined Contributions (NDCs): Evolving Commitments
Before exploring what individuals can do, let’s first reflect on what governments have achieved so far and how they are expected to address transportation emissions through NDCs, which outline each country’s plan to combat global warming by reducing greenhouse gas emissions under the Paris Agreement. The first two rounds—NDC1.0 and NDC2.0—made significant progress in energy and agriculture but largely overlooked transportation. However, with transportation now accounting for one-quarter of global GHG emissions—80 percent of which comes from road transport—and consuming half of the world’s oil, countries are urged to prioritize this sector in their NDC3.0 submissions.
According to Our World in Data, emissions vary widely by region: the United States has some of the world’s highest per capita transportation emissions, at 5.0 metric tons, due to high car ownership and suburban sprawl. China, at 0.7 metric tons, and the European Union, with 1.5 metric tons, use extensive public transit to lower their totals. The United Kingdom is at 1.7 metric tons, with a good rail and bus network. India’s emissions are 0.2 metric tons, and Africa’s are 0.3 metric tons; emissions for both India and Africa are still relatively low due to lesser motorization.
As governments are expected to set high ambitions for reducing transportation’s Global Warming Potential by electrifying transport, improving fuel efficiency, and expanding public transit in the upcoming NDC3.0 submissions due in February 2025, it is essential to consider how individuals could play an equally important role. After all, much of this challenge stems from our daily reliance on private vehicles, making it essential to examine the growing impact of private transport on the climate crisis.
The Rise of Private Transport: A Growing Carbon Skyline
While car dependency is a global issue, the United States provides a key case study on the impact of private transport and the opportunities for change due to its exceptionally high vehicle ownership—ranking second only to New Zealand in private vehicles per capita. Urban sprawl and cultural norms of car ownership continue to increase private vehicle use. Vehicle miles traveled (VMT) increased 50 percent between 1990 and 2022—far outpacing population growth— private vehicle use contributing to nearly 60 percent of US transportation emissions. Notably, 70 percent of VMT occurs in urban areas, emphasizing the reliance on private vehicles in densely populated regions. This dependence contributes to increased congestion, higher emissions, and added strain on already challenging urban infrastructure, further intensifying the severity of the climate crisis.
The Environmental Cost: A Global Imbalance
Between 2010 and 2023, global annual emissions from passenger vehicles surged by about 20 percent, reaching 3.2 GtCO₂-equivalent—comparable to destroying over 3 billion acres of forest. That’s more than twice the size of the Amazon Rainforest, one of the world’s most vital carbon sinks, which spans approximately 1.4 billion acres. This staggering loss contributes to extreme weather, accelerates rising sea levels, and drives biodiversity decline, deepening the climate crisis.
This impact is not uniformly distributed; car-dependent nations and regions emit disproportionately, so policy solutions must be tailored to local realities. However, beyond policy, individuals also have the power to drive meaningful change.
Introducing Individually Determined Contributions (IDCs)
Referring to NDCs, an outline of a country’s commitment to climate action, we can think of IDCs as the small, daily personal actions we can take to create a healthier planet. Regarding transportation, IDCs for transportation are simple, everyday choices that reduce our reliance on private vehicles.
For example, walking or biking just one mile instead of driving saves around 0.8 pounds of CO₂, equivalent to charging a smartphone about 30 times. We can help shrink the towering carbon skyline by continuously performing these small actions. By relying less on private vehicles, people reduce emissions and encourage their communities to adopt more sustainable transportation options. This good example results in healthier communities from increased physical activity, better air quality, and economic savings due to reduced fuel consumption, which improves public health, quality of life, and environmental resilience.
2025 Resolution: Building Better Habits for a Sustainable Planet
As we step into the new year, let’s commit: We can begin by eliminating one car trip per week—walk, bike, or take the bus. Link errands together or carpool with neighbors to reduce trips. Gradually raise your goals and celebrate each milestone. Work with others to hold each other accountable. By year’s end, you will take pride in the total harm you have prevented. Although small steps may seem insignificant, they could inspire your friends to do the same, creating a snowball effect across communities. As these habits become more solidified, they build momentum for even more environmental goals.
A Hopeful Future
Even as the carbon skyline looms above us, we can tear it down. Every private car trip we avoid, every mile we walk or bike, shrinks its height and brightens our common horizon. Embracing IDCs paves the way for cleaner air, healthier communities, and thriving ecosystems while complementing NDCs to accelerate global progress. Our actions and national commitments can transform our planet into a healthier, sustainable home for current and future generations.
Reader Questions:
What IDC can you commit to today to reduce your transportation emissions? Who can you invite to set IDCs with you and make an even more significant impact?
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The Institute for Climate and Sustainable Growth is a collaborator of the UChicago Sustainability Dialogue, but is not responsible for the content.