Caring for Patients While Caring for the Planet: Understanding the Carbon Footprint of Clinical Research

Clinical trials must innovate to keep sustainability alongside safety, speed and efficacy as a core consideration.

Clinical trials are essential to advancing medicine, but they come with an environmental impact that has been historically overlooked.

Research shows a single clinical trial can generate up to 3,000 metric tons of CO₂ equivalent gasses (mT CO₂e)—about the same as the annual emissions of 176 energy-hungry Americans. When you consider the scale of a single pharmaceutical company’s clinical pipelines, the carbon footprint can rival that of entire island nations like the British Virgin Islands or Turks and Caicos.

As climate change accelerates, we must ask ourselves: How do we advance human health without compromising the health of our planet?

Climate change is a health crisis

The Intergovernmental Panel on Climate Change (IPCC) is clear: The climate crisis is also a public health emergency.

From clean air to safe drinking water and stable food systems, human well-being is deeply dependent on natural ecosystems. Rising temperatures are expanding the reach of infectious diseases, threatening agriculture, disrupting access to safe water, and displacing vulnerable populations.

In short: Planetary health and human health are inseparable, interrelated and interdependent.

What’s causing emissions in clinical trials?

While the industry has made major strides in patient-centricity and scientific innovation, the environmental impact of clinical trials has historically gone largely unaddressed and has likely increased as trials have gone global and gotten larger.

Jason LaRoche and colleagues recently published in BMJ Open an overview of the carbon footprint for seven industry-sponsored trials across various phases. The findings were eye-opening:

• Small Phase 1 trial: ~17.6mT CO₂e – on the order of the annual carbon emissions¹ of someone from North America
• Large Phase 3 trial: Over 3,100mT CO₂e – on the order of driving 700 gas-powered cars for a year

For context, the average American produces about 14mT CO₂e per year. These trials far exceed that footprint, especially as scale increases. Further, a 14mT lifestyle is broadly considered unsustainable, and many suggest we need to begin stepping this down toward 5mT¹ and eventually zero.

So where do these emissions come from in a clinical study? The study identified five primary contributors:

1. Investigational product and drug product manufacturing/distribution (~50%)
2. Patient travel (~10%)
3. On-site monitoring visits (~10%)
4. Laboratory sample processing (~9%)
5. Sponsor staff commuting (~6%)

In the analysis, patient travel was the only hotspot that consistently appeared in all seven trials considered. Additional hotspots often include investigator meetings, site utilities, and shipping of supplies and biological samples based on additional literature and our internal data analysis.

Why we need carbon calculators

One of the biggest challenges in reducing clinical trial emissions is knowing where to look. Not all studies have same key drivers of emissions or “carbon hotspots.” When you step on a plane, you know the greenhouse gas emissions that come from burning the jet fuel far outstrip the emissions from your onboard cup of coffee. However, every time you celebrate first patient, first visit, we can’t blindly attribute emissions based on the above breakdowns without some analysis. For example, we can’t say that all studies will have investigational products as a hotspot: What if you are running a noninterventional study?

That’s where carbon assessment tools, such as clinical trial carbon calculators, play an important role. These tools help sponsors, researchers, sites, clinical research organizations and other stakeholders:

• Approximate emissions from study operations to investigational product manufacturing
• Identify high-impact areas, or “carbon hotspots,” like travel, manufacturing or utilities
• Compare study designs (e.g., site-based vs decentralized) in terms of environmental impact
• Support data-driven decisions early in trial planning that align with sustainability goals

For example, a site-based Phase III study with numerous visits over a long period of time, may see much higher emissions from facility energy use, patient travel and staff commuting, compared to a decentralized observational study with limited on-site visits.

Having a clear understanding of these drivers allows trial designers to consider meaningful changes—like remote monitoring, digital recruitment, or centralized labs—to reduce emissions without sacrificing quality or compliance.

A shared responsibility

Sustainability in clinical research isn’t just the job of trial sponsors. It involves the entire ecosystem:

• Vendors offering more efficient transportation, packaging and event planning
• CRAs and staff optimizing travel to reduce visits where possible
• Protocol designers minimizing unnecessary burden on patients and resources
• Sites managing energy use and waste, and encouraging remote monitoring visits and patient travel options

Collaborative efforts, like industry working groups and environmental advocacy initiatives, are beginning to elevate this conversation and provide practical guidance. Raising awareness and setting expectations early in the trial life cycle is critical for progress.

Toward a more sustainable future

Clinical trials are a cornerstone of human health innovation. But as we move forward, we must also innovate how we conduct them, keeping sustainability alongside safety, speed and efficacy as a core consideration.

Because at the end of the day, a healthy future for people depends on a healthy planet.

Let’s ensure the way we advance medicine also protects the world we live in.