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Yale scientists led a study on the multi-hazard effects of climate change in the rapidly urbanizing Himalayan region — the culmination of years of multi-institutional collaboration and interdisciplinary research. 

The research team, consisting of primary contributor and graduate student Jack Rusk, Yale Professor of Geography and Urbanization Science Karen Seto, her lab members, the University of British Columbia, Kumaun University and partnering international agencies, published an article detailing their findings in the journal Science of the Total Environment on Sept. 13. The team credited their efforts to a generous monetary fund and satellite data from NASA. The grant was part of NASA’s focus on sponsoring studies that investigate how urbanization is changing the Earth’s surface over time, Rusk said. 

“Right after the Nepal earthquake [in 2015], it became clear that there is very little understanding of … the intersection between urban development and hazards,” Seto explained, speaking to the motivation behind the project. 

With increasingly unpredictable Californian wildfires and large hurricane events, the United States has seen its share of climate-related hazards in recent years. The researchers, however, discuss that the story is different when told from the perspective of developing countries. While urbanization is a “dominating force in the 21st century,” according to Rusk, its effects “are heterogeneously distributed.” 

In Nepal, urban development has attracted people to cities due to the relative abundance of education, economic and social opportunities and healthcare services, Rusk said. As a result, 49 percent of the population is highly concentrated within a small number of urbanized areas. These places suffer particularly high casualty counts and the destruction of infrastructure when hazards, namely floods, landslides and fires, strike, according to student project researcher Emma Levin ’23. 

In trying to carry out their research, the scientists found that the region’s highly mountainous topography not only made satellite observations challenging, but also contributes to the region’s vulnerability to certain hazards. According to Levin, people tend to live in areas where there are more risks, and that climate change is the driving force behind recent increases in the incidence and intensity of said hazards.

The project also emphasized understanding connections between how different hazards occur and interact with one another rather than focusing on individual risks. 

“The way that hazards are managed right now in the Himalayas … you may have one agency managing forest fires … and another land agency managing landslides because they have that mandate,” Rusk said, claiming that a specialized approach may not be effective. 

Solutions for one type of hazard can become tradeoffs that increase the possibility of another type happening. To help contextualize this relationship, Rusk gave the example of clearing vegetation to create firelines that can then prevent fires, only to leave behind bare soil susceptible to landsliding. 

In its study, the team drew upon both quantifiable research methodologies — including data science, mathematical equations and modeling from space — with other techniques, such as local workshops and interviews. The researchers also connected with partner organizations and social scientists in Nepal, according to Levin and Rusk. 

By offering resident perspectives and providing on-the-ground expertise that complemented satellite data, these partnerships were especially helpful during the pandemic, when the team of researchers was not able to stay in the Himalayas for extended periods of time. It was the constant coordination between the Nepalese and Indian organizations that allowed the researchers in New Haven to make sense of their observations from space.

Rusk believes that this combined approach shows that “big data science” is only one part of any scientific project. What is also central to the discussion is the human side of things — specifically, how this science “square[s] with the understanding of people on the ground, ethnographers and anthropologists” and making that information from space and the lab accessible to local experts, community members and government officials who can then collaborate to engineer potential solutions, he said. According to Rusk, multi-hazard approaches are currently being trialed in the Himalayas. 

The complete research paper can be accessed online here

BRIAN ZHANG
Brian Zhang is a first year in Davenport College.