The Carbon Footprint of Clinical Trials

Although the healthcare industry is responsible for saving millions of human lives, its current operations have a significant impact on the environment. More specifically, estimates suggest that 4.4 to 4.6% of worldwide greenhouse gas (GHG) emissions are released by the global healthcare industry.

In terms of the carbon footprint of clinical trials, one recent study estimates that the emissions attributed to the over 350,000 national and international trials are equivalent to 27.5 million tons of GHG emissions. To put this value into perspective, the emissions released by clinical trials alone are a little over 30% of the total emissions released by the nation of Bangladesh, which is a country home to over 163 million people.

Clinical Trial

Image Credit: Den Rise/

How do clinical trials cause increased GHG emissions?

Notably, almost half of all clinical trials investigate novel drugs, which account for up to 20% of the carbon footprint of the National Health Service (NHS) of England. Both upstream and downstream processes within the pharmaceutical industry contribute to their carbon emissions.

The upstream processes within the pharmaceutical industry that are associated with high energy costs include the manufacturing and researching of drugs, as well as the high transportation costs for drug distribution. Furthermore, manufacturing byproducts within this industry, which are often referred to as pharmaceutical waste, are also considered significant environmental problems.

In fact, a 2019 study estimated that an additional 23,000 to 105,000 metric tons of CO2 each year was generated from unused quantities of eyedrops, ocular injections, and systemic medications that are prescribed following cataract surgeries alone.

Aside from the production of drugs that are used in clinical trials, there are also several other aspects of the clinical trials themselves that contribute to their large carbon footprint. One recent study of a sample clinical trial found that the trial coordination center for this study alone was responsible for 39% of the trial’s total emissions, which was equivalent to 50 tons of CO2. Out of these 50 tons of CO2, 45 was directly linked to electricity usage, with the remaining 5 tons due to office waste disposal.

The next largest producer of CO2 in this study was the distribution of drugs and documents, which amounted to 35 tons of CO2. The majority of these emissions were due to airfreight of treatment packages or documents that were sent to hospitals. Trial-related travel, which was responsible for 29 tons of CO2, primarily included air travel, as well as hospital, stays for site visits, on-site data verification, and meetings.

Approaches to reduce the carbon footprint of clinical trials

In 2007, the sustainable Clinical Trials group published several guidelines for reducing the carbon footprint of clinical trials. These guidelines were found to improve the carbon efficiency of trials through a more rapid patient recruitment process, reducing the weight of trial materials, and allowing for data entry to be shifted to web-based. Through the implementation of these efforts, a 2009 study of 12 randomized trials found that the average carbon emission of these U.K.-based trials was equivalent to that of nine people in one year.

Despite these improvements since 2007, few additional efforts have been made to reduce the carbon consumption of clinical trials, aside from the U.K. National Institute for Health Research (NIHR) Carbon Reduction Guidelines. Thus, there remains an urgent need to develop tools that are capable of adequately measuring the carbon footprint of clinical trials and assist in the identification of exactly which elements of the trials are likely to be carbon-heavy.

Recently, NHS England has introduced the Sustainable Healthcare Coalition, which consists of triallists, clinicians, commercial suppliers, and others within the public health sector to reduce the carbon footprint of clinical trials to zero. To achieve this goal, this coalition has developed a novel tool that will be used to measure the carbon footprint of trials and provide benchmarking values.

Several other recommendations have been put forward to support this goal. For example, any individual who has a role in planning a given clinical trial should perform a systematic review to identify the value of the carbon that will be used throughout the trial. This information could be incorporated into the grant application that is accompanied by possible methods to reduce the carbon footprint, such as through the use of NIHR guidelines.

It has also been proposed that incentives could be provided to trials with lower carbon footprints. This would not only prioritize funding trials with lower carbon requirements but will also require researchers to justify the carbon footprint to their stakeholders.


Further Reading

Last Updated: Jun 6, 2023

Benedette Cuffari

Written by

Benedette Cuffari

After completing her Bachelor of Science in Toxicology with two minors in Spanish and Chemistry in 2016, Benedette continued her studies to complete her Master of Science in Toxicology in May of 2018. During graduate school, Benedette investigated the dermatotoxicity of mechlorethamine and bendamustine; two nitrogen mustard alkylating agents that are used in anticancer therapy.


Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Cuffari, Benedette. (2023, June 06). The Carbon Footprint of Clinical Trials. News-Medical. Retrieved on June 17, 2024 from

  • MLA

    Cuffari, Benedette. "The Carbon Footprint of Clinical Trials". News-Medical. 17 June 2024. <>.

  • Chicago

    Cuffari, Benedette. "The Carbon Footprint of Clinical Trials". News-Medical. (accessed June 17, 2024).

  • Harvard

    Cuffari, Benedette. 2023. The Carbon Footprint of Clinical Trials. News-Medical, viewed 17 June 2024,


The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
Children can boost vaccination rates by educating their grandparents