Loan Diep, a Research Scientist active in New York City, explains the consequences of the changes within the National Nature Assessment (NNA), the importance of transnational research on climate adaptation, strategies to support research, and nature-based solutions in cities like the city-wide tree planting initiative in Freetown (Sierra Leone).
ClimateAdaptation.life: The National Nature Assessment (NNA) has been recently terminated. What are the possible consequences for climate change adaptation measures?
Loand Diep: The NNA was initially launched by the Biden-Harris administration in 2022 as a national project and led by the U.S. Global Change Research Program, a network of 15 federal agencies that tackle environmental issues. The NNA was conceived as the first ever assessment of its kind, on the benefits provided by natural resources across the country. It’s brought together about 170 scientists, collaborating on different chapters: climate projections, human health, equity, and more. When the new administration came to power on January 20 of this year, it adopted an executive order that terminated it. But the NNA is continuing, independently. This type of assessment is important to prepare for climate change, halt biodiversity loss and inform future decisions on managing natural resources - without it, we are essentially moving in the dark.
What are the parts of the society which could be mostly exposed to the change? How does it relate to politics in the US and globally?
Everyone is exposed to climate change, but groups that suffer from structural inequities, often correlated with race and economic status among other factors, face higher risks because climate change aggravates pre-existing struggles. Take New York City: 49% of the population lives in environmental justice areas. These are disadvantaged communities that are more vulnerable to heat stress and flooding because they live in exposed areas and also may lack the means to prepare or respond to extreme events. Black New Yorkers are two times as likely to die from heat-related causes as white New Yorkers. They are also more exposed to polluting infrastructure like waste generators and hazardous storage facilities. These are linked to exclusionary zoning, disinvestment, and overall histories of oppression and discriminatory practices in the U.S., but comparable issues have also existed in other cities worldwide. It’s important to keep raising visibility around these often-misunderstood issues so we act to best address them.
In general, what was/is the role of NNA in assessing and understanding nature and climate change? Why is it important to assess nature to understand climate change and possible related damages?
First of all, it’s important to clarify what we mean by “nature”. Every ecosystem is complex, with its own dynamics, and understanding how each responds to external pressures helps us see the role nature plays as a buffer under stress. Trees, for instance, allow water to infiltrate soils, absorb carbon, and while mitigate storms. When we lose them, ecological health keeps degrading, and we also lose the protection they provide and put lives at risk. But all these processes are extremely complex, and that’s why assessments are so valuable: they allow us to evaluate how different ecosystems react under different conditions, and how we can prepare effectively for climate change.
How can the research be done also without federal funding? Could eventually other countries take over the central role of the US in understanding climate change and designing measures to adapt to climate change?
Funding for research can come from different sources. The NNA now benefits from new streams of support. Many scientists have been part of the process on a voluntary basis, a model similar to the IPCC, which has its pros and cons. The NNA itself focuses on the United States, but there is a real need for other countries and regions to carry out their own assessments and design measures tailored to their contexts. That’s the point we have wanted to convey in this commentary piece. Ensuring that such processes are adequately supported, both financially and institutionally, will be key to making them inclusive, representative, and impactful.
Would you be able to assess the ripple effects of NNA's termination on research activities in other geographies? In general what's the effect of slower research on climate adaptation?
Slowing down research on climate change means slowing down action and increasing risks of damage caused by climate events. When the NNA was launched this increased hope that it would spur similar initiatives in other countries. However, this type of assessment requires political initiatives, resources and capacity. Thankfully the NNA initiative is continuing and is now called “United by Nature”. It is difficult to predict the range of direct and indirect effects of the project’s termination beyond the immediate impacts that were observed at the onset of the decision and during the subsequent limbo period, but overall, it would certainly have represented a missed opportunity, including given the months of hard work already invested. Most fundamentally, we cannot afford such delays: the urgency of the moment leaves little time to lose.
Are there other institutions/subjects that could help create a network to jointly work on climate change adaptation measures?
Many institutions, including non-governmental ones, have been ready to step up to support the continuation of the work conducted by the United by Nature teams. But beyond initiatives like United by Nature, there are many other ways that people have shared learning and took climate action. Some of them are more bottom-up and focus on integrating different ways of knowing, and gather knowledge on lived experiences from people on the frontline. At the end of the day, universities, city networks, grassroots organizations, Indigenous groups, and youth movements all play a role. Each brings different strengths, whether it’s with data analyses, local knowledge, or the ability to mobilize communities. What really matters is creating spaces where these actors can learn from each other, align their efforts, and combine resources. Our global network NATURA aims to serve this purpose of building bridges.
What's the role of collaboration in defining climate change adaptation measures that really work? What's the role of science to make them replicable and financially sound?
Collaboration is essential because no single actor or discipline holds all the answers to climate adaptation. Some networks already work on connecting academic with on-the-ground knowledge, and that’s exactly what we try to do with NATURA: fostering collaboration for knowledge integration around nature-based solutions, with a focus on cities. We bring together people from different disciplines, sectors, and world regions (from universities to NGOs and community groups), because there’s no one-size-fits-all solution. Adaptation needs to be shaped by context.
Science plays its own role here, especially in helping us understand what actually works, under which conditions, and for how long. One of the key lessons from NATURA’s Global Roadmap for Urban Nature-Based Solutions project is the importance of monitoring and evaluation: without it, we can’t tell which approaches are effective, which can be scaled or replicated, and which are worth the investment. Yet monitoring and evaluation remain largely absent in cities across regions, and filling that gap is where science can make a real difference in ensuring adaptation measures are both replicable and financially sound.
And what is the potential of climate change adaptation measures in vulnerable urban areas like favelas and slums?
Climate adaptation measures like nature-based solutions are often most absent in the very places where they’re needed most: so-called “informal” settlements. In cities, these neighborhoods are frequently located in high-risk areas, exposed to floods, heat, air pollution and other hazards. At the same time, residents often lack reliable access to basic services like water and sanitation, as well as green spaces; all while facing constant threats of displacement. Today, an estimated 1.1 billion people worldwide live in what are considered informal settlements. If designed and implemented with sustainability at the heart, nature-based solutions there could help tackle these compounded risks together. What’s important to know is that many of these communities are already experimenting with their own adaptive greening practices at their own scale, from rooftop gardens to water harvesting, showing that greening initiatives don’t only come from formal planning. Yet in practice, the most elaborated and financially supported nature-based solutions are far more likely to be built in wealthier districts, which only widens the gap between those who benefit and those left out.
Is there any specific climate change adaptation measure that particularly impressed you in this field?
For me, the focus is less on any single technique and more on the approach and the process. The initiatives that tend to endure are those that take a systems perspective, bringing together social, political, ecological, and technological dimensions. The powerful example that I always present first is the city-wide tree planting initiative in Freetown in Sierra Leone, known as the #FreetownTheTreetown campaign. What stands out is not just the planting itself, but how the initiative was designed and sustained across multiple scales and made space for the participation of the population, including the most marginalized groups of the city. Much of its success is thanks to the vision and dedication of my late colleague, Eric Hubbard, who played a key role in helping the campaign take root and thrive.
Could you also briefly explain your role, your story and your relationship with climate change adaptation measures?
I am dedicated to supporting the green and sustainable development of cities, in ways that are socially inclusive. I strongly believe that we can’t tackle environmental issues without also addressing social inequalities, and vice versa, that nature is an essential part of the equation when it comes to redressing those inequalities. Through the network NATURA, my role is to support collaborations among people working along the same pathways for change. I currently work as a Research Scientist in New York City, but before moving to New York, I studied and learned from river management initiatives in informal settlements in Brazil. Although my work currently has a global scope, I am also looking to develop a stronger focus on local, on-the-ground actions in parallel.
Loan Diep discusses the termination of the U.S. National Nature Assessment (NNA) and its implications for climate adaptation research and policy. The NNA, launched in 2022 to assess the benefits of nature for climate resilience and human well-being, was halted by a change in administration but continues independently as “United by Nature.” Diep argues that losing such assessments weakens decision-making, increases climate risks, and delays urgently needed adaptation action.
The interview highlights that climate change disproportionately affects marginalized communities, particularly in cities like New York, where environmental justice areas face higher exposure to heat, flooding, and pollution. These inequities are rooted in historical discrimination and require sustained political and scientific attention.
Diep emphasizes the importance of assessing ecosystems because nature acts as a protective buffer against climate impacts. Research, even without federal funding, can continue through international cooperation, voluntary scientific networks, and support from non-governmental institutions, but delays in research slow adaptation and raise risks globally.
Collaboration across science, governments, communities, and grassroots organizations is essential to design effective and context-specific adaptation measures. Science plays a key role in monitoring and evaluating what works, making solutions scalable and financially viable. Nature-based solutions are especially promising for vulnerable urban areas, including informal settlements, but are often underfunded where they are most needed.
A standout example is Freetown’s city-wide tree-planting initiative, which combines ecological benefits with strong community participation. Overall, Diep stresses that climate adaptation must integrate social equity, local knowledge, and nature-based approaches, and that delaying research and action is a cost the world cannot afford.
