EarthLab summer interns share how their projects supported an upcoming economic analysis on the cost savings of spending time in nature and highlight the vital role science plays in shaping effective green space policy.
Written by Solveig Smith, 2025 Nature and Health Science Communications Intern
When policies are grounded in solid evidence, everyone benefits. Research-backed decisions lead to smarter programs, better infrastructure, and tangible improvements in public health and well-being. Think about cleaner air thanks to updated emissions rules, food safety standards that prevent sickness, or expanded public transit that eases congestion.
Research isn’t enough on its own. It has to reach and resonate with those who make decisions. That’s why it’s so important for researchers to clearly and effectively communicate their findings to policymakers. While it may take a while to build meaningful relationships, hone communications strategies, and attend public meetings, the effort culminates in policies that enhance public health and well-being.
At the Center for Nature and Health (the Center), interns in the 2023 EarthLab cohort sought to find out how the Center could better engage in evidence-based policy. Through research, interviews, and literature reviews, they found stakeholders—including government officials, nonprofit partners, and private sector donors—were looking for concrete numbers on how access to green spaces reduces healthcare costs.
Fast forward to the summer of 2024, where another cohort of interns conducted a comprehensive literature review. They poured over peer-reviewed papers from around the world to tabulate how spending time in nature can reduce healthcare costs and provide other quantifiable co-benefits, such as increased quality of life, improved mental health, increased productivity, reduced premature deaths, and more.
One outcome of the interns’ groundwork is the upcoming economic analysis, Quantifying the Cost Savings of Spending Time in Nature, led by an interdisciplinary team at the University of Washington. The project will calculate the financial savings of time spent in nature in Washington state. With quantifiable cost savings, policymakers, community-based organizations, individuals, and other stakeholders can better advocate for increasing equitable engagement with green and blue spaces. Shaped in part by the interns’ work, studies like this attempt to answer stakeholder needs while centering expert advice.
During a summer 2025 informational interview, the Center’s former interns Rohini Achal and Hope Flanigan shared how their internships contributed to evidence-based policy. Rohini is pursuing a master’s in public health from Johns Hopkins Bloomberg School of Public Health and is a population health policy analyst for AHCA/NCAL. Hope recently graduated from the UW School of Public Health with a degree in public health-global health and is interning with the Tacoma Tree Foundation.
Interview responses have been edited for brevity and clarity.
Q1: As a policy intern in 2023, what did your research, policy review, and interview process look like? What were your primary findings?
Rohini Achal: For our project, we reviewed over a hundred pieces of text. It wasn’t just studies. It was legislation, bills, and all sorts of things. I remember, in relation to this project, that there wasn’t much research on the cost savings of spending time in nature. Tennessee had an interesting program—Healthy Parks, Healthy Person Tennessee—where they were trying to reimburse folks for time spent in nature. Few people had studied that in the U.S. Our recommendation, which is pretty much the recommendation of every researcher, is that you need more studies. That’s where the Center is going with this upcoming project. We need more financial data, especially to get buy-in from insurers. The majority of what I do now is health insurance-based, and for insurance plans, the bottom line is financial. You need tangible evidence and statistics demonstrating that time spent in nature benefits human health while simultaneously lowering healthcare costs.
Q2: In 2023, your final intern project included a list of evidence-based policy recommendations for the Center for Nature and Health. How did you land on these recommendations?
Rohini: We were looking at ways for the Center to get involved in the policy world, especially at the state and local levels. The main goal was how we could insert ourselves into the policy landscape. As for the recommendation to study the monetary impacts of green space on health, we heard from stakeholders that healthcare policy requires buy-in from insurance plans. We found that it was important, more broadly, to ensure policymakers have an understanding of the tangible economic benefits or risks of adopting the nature-related policy.
Q3: As a Healthcare Cost Savings intern in 2024, your final project included a literature review on the co-benefits of time spent in nature. What did your research and literature review process look like? What were your primary findings regarding research trends on this subject?
Hope Flanigan: Our project started with having conversations about what the literature review would be used for. It required a lot of conversations about paring down our exclusion and inclusion criteria, while still getting a useful end product. My co-intern and I searched databases together, read through the papers, and talked to better understand them. It’s a difficult area of research to synthesize findings because there is a lot of developing methodology. The majority of studies were within the United States, the United Kingdom and Australia, and largely white and affluent populations. This research is largely focused on those populations. There’s a long history of redlining and environmental racism that contributes to this divide in access to nature. It’s important to expand representative research.
Overall, we saw significant improvements in mental health conditions and reduced healthcare costs in varying degrees. A lot of savings were measured in preventable deaths and diseases. Then across the papers, there was the equigenic effect. That is, areas of lower socioeconomic opportunity, or historically marginalized communities, often see greater benefits when having access to green space compared to predominantly white or affluent areas.
Q4: In your respective projects, what challenges came up while researching and writing about this topic?
Rohini: We talked to so many people. There were also different opinions on what to do next. There were so many different directions we could have gone in. We learned you’re not always going to achieve consensus, but it’s still critical that everyone comes to the table and shares their knowledge. I’m learning that in my new job, too, and building on that knowledge.
Hope: It was challenging to sift through co-benefits research and pull out the pieces that speak to each other across the literature. It was definitely a skill that took developing. Another challenge was being flexible. I would spend a whole day reading research papers. Then we would have a meeting and we would decide none of these papers are going to be included. While you learn a lot, it’s not a part of the final product anymore and that flexibility is necessary. In school, you’re so used to getting a project, finishing it, and getting a grade. But this project was started the summer before by the past interns who identified this policy area. And then we spent a summer working on the research. Gaining a better understanding of how long things take was really crucial and eye-opening.
Q5: After spending a summer learning about these subjects, what were your takeaways regarding the healthcare savings and co-benefits of time spent in nature? Are there any authors or particular research that interests you most?
Hope: The internship really solidified my passion for connecting nature and health. In terms of a public health intervention perspective, urban greening and access to green space is one of the lowest cost, but highest benefit interventions we have for mitigating so many types of health problems. It helps with mental health, physical well-being, prevention of disease, and social inclusion. And it’s trees! If it’s in a community, it’s benefiting everybody. Even if people aren’t accessing it directly, it has greater positive ecosystem effects. I think it’s powerful in understanding how green space fits into healthy and thriving communities.
In terms of particular researchers, Douglas Becker, Matthew Browning, and Stephen K. Van Den Eeden come to mind. They were really prominent across the literature that we read, and most of their research was in the United States looking at Medicare level data and NDVI data on green space. Their research was interesting in terms of developing methodology and using publicly available data. I would love to see where that goes.
Rohini: Something I’ve learned through this experience—and through my work in politics and public health—is that there’s a lot of variation between states. The United States has an individualistic approach to policy, while public health takes more of a community and population approach. What may be traditionally thought of as progressive green space policy can align with an individualistic approach. In the Healthy Parks, Healthy Person Tennessee program, even though there is a system involved in prescribing folks to go out in nature, it’s up to individuals to go out and do it themselves. That’s different from policy that expands equitable access to green space for everyone.
Q6: How did your internship experience inform your next steps?
Hope: It made me excited to take a gap year, take a deep breath, and explore more options. One of those is environmental justice work. Through the Center, I became connected with the Tacoma Tree Foundation. That opportunity has been really great in terms of my own development. I feel more connected to the local context where I grew up and how I first became passionate about environmental justice.
Rohini: It really shaped what I’m interested in and what I’m not interested in. I didn’t know what my niche was. I think that EarthLab really helped me with how I wanted my career and future employment to look like. A lot of our project was reviewing legislation, reviewing policy and data, which is what I do now. I loved having that experience while I was still in undergrad because it gave me needed exposure to environmental policy early in my public health career. It also solidified that I love health policy!
Q7: The Center is beginning an economic analysis this fall. The goal is to produce estimates of healthcare savings in Washington state to inform policymakers about the benefits of expanding access to nature. It seeks to provide evidence for more policies and programs that support equitable access to green spaces. Did you envision the work you performed leading to a funded research project? How does that feel?
Hope: It’s a fun question to think about. Did we envision it? I would say, yes. We were hopeful and wanted it to go forward because we really believed in it.
In terms of how that makes me feel? Very proud to be a part of a project that’s been going on for so long, and that’s hopefully going to have an impact in Washington. I think that local context is super important. And it wasn’t something we really found in the research. I don’t think there were any studies that were specific to the Pacific Northwest, so it’ll be amazing to have that data and that research. Especially in my role now working on advocacy at Tacoma Tree Foundation, and understanding the importance of having that data to bring to decision-makers. I think it really does have a role in prioritizing funding for green space and urban forestry initiatives. Having those tangible estimates is really important.
Rohini: I don’t think Amy Flores, my co-intern, and I thought that at all. We were just thinking that if our paper gets shown to the Nature and Health Steering Committee, maybe someone will take it upon themselves to look more into any of our recommendations. I don’t even think we thought a fully-funded study was in the scope of things. We knew that we needed more comprehensive research. If further research indicates benefits, that’s even better. So it’s great, that’s awesome to hear, and I’m really happy that the Center is filling that gap!
Conclusion
Seemingly brief nine-week internships can have a long-term, worthwhile impact. As the Center explores more policy initiatives, future interns will continue to support projects like this. To get involved in successful policy, the Center listened to stakeholders, found research gaps, and will respond to them with meaningful data. Financial incentives can unite differing interests to produce change. This effort will hopefully translate into real community benefits and green space growth in the future.