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The Nicholas School of the Environment welcomes Liyin He as an assistant professor in the Division of Environmental Sciences and Policy. He, who officially joined the faculty on Jan. 1, uses data from satellites and other remote-sensing instruments to understand how climate change affects crop production and human health, with the goal of improving agricultural management practices and policies and climate change mitigation efforts.

“I’m interested in the impact of climate change on human activities. For example, if there is continued warming and more carbon dioxide in the atmosphere, we anticipate it will have an impact on crop yield, which will then affect global food security,” He said.

As an undergraduate at Nanjing University in China, He took an introductory remote-sensing course and was hooked. While pursuing a Ph.D. in environmental science and engineering at the California Institute of Technology, she developed a new remote-sensing method to evaluate plant health.

A common method of assessing vegetation involves measuring plant density, or greenness. However, clouds, soil and even abundant growth can affect accurate measurements. He’s approach avoids those problems. The technique uses satellites to detect fluorescing molecules emitted during photosynthesis, the process by which plants convert sunlight into energy. This solar-induced fluorescence provides a more precise picture of plant health that can subsequently be used to predict crop yield, He explained.

Monitoring photosynthesis can also enable other climate-related insights, such as how much carbon dioxide is being absorbed by land-based ecosystems and how plants are responding to droughts and natural disasters, according to He.

As a postdoc at the Carnegie Institution for Science, He expanded on her graduate work to develop models that predict how different management practices, such as , can mitigate the effects of climate change on crops. She also expanded beyond plants to humans, using satellite data to study links between .

“We can use remote-sensing data to identify unequal exposure to heat stress or air pollution for groups with different incomes or risks,” she explained, “and we can find suitable or effective strategies to help them address these risks. I really feel passionate about this work.”

The promise of transdisciplinary research drew He to the Nicholas School. Using AI, machine learning and satellite remote sensing, she hopes to draw connections between historical climate data and ecosystem responses to better understand how climate change will shape the environment.

He is particularly interested in parsing fundamental ecological processes and translating that knowledge into applications that benefit society. Her planned research will investigate ways to improve agricultural management to support food security; mitigate urban heat to bolster public health; and enhance forest management to increase carbon sequestration.

“If we can develop some empirical relationships based on historical data sets, then we can help guide future management practices and develop policies to mitigate climate change,” He explained.