CMI Best Paper Awards recognize work on carbon capture, irrigation’s climate impact

Morgan Kelly ・ High Meadows Environmental Institute

The Carbon Mitigation Initiative (CMI) recognized Tom Postma, a Ph.D. candidate in civil and environmental engineering, and Yujin Zeng, an associate research scholar in atmospheric and oceanic sciences, at the CMI Annual Meeting for outstanding published research.

Postma was awarded the Robert H. Socolow Best Paper Award for Doctoral Students and Zeng received the Robert H. Socolow Best Paper Award for Postdoctoral Fellows. CMI Director Stephen Pacala, the Frederick D. Petrie Professor in Ecology and Evolutionary Biology, announced and recognized both awardees April 27 during the CMI welcome and meeting overview session.

Since 2010, CMI has presented best paper awards to postdoctoral fellows working with CMI faculty members based upon their contributions to important CMI papers. CMI created the award for doctoral students in 2019. Both awards are named in honor of Robert Socolow, professor of mechanical and aeronautical engineering, emeritus, at Princeton and the codirector of CMI from 2000-2019. CMI is an independent academic research program based at Princeton and administered by the High Meadows Environmental Institute (HMEI) that includes 16 principal faculty investigators and over 50 research staff.

Postma was recognized for his CMI-supported paper, “Field-scale modeling of CO2 mineral trapping in reactive rocks: A vertically integrated approach,” which was published in the journal Water Resources Research in November. His co-authors included Postma’s adviser Michael Celia, Princeton’s Theodora Shelton Pitney Professor of Environmental Studies and director of HMEI from 2017-21.

The paper developed an efficient numerical method for simulating large-scale carbon capture and storage (CCS) in basalt formations. The chemical conversion of carbon dioxide into solid carbonate — a process known as mineral trapping — is the most stable and secure trapping mechanism in CCS. Small-scale experiments have shown that basalt formations could allow mineral trapping to occur on relatively short timescales (months to years) due to their large proportion of highly reactive minerals.

However, there are still open questions that need to be addressed before CCS in basalt can be implemented at a large scale, including how decades of chemical activity will alter the properties of the target formation. Postma and his co-authors developed an efficient way of simulating the combination of chemistry and two-phase fluid flow in the subsurface, which can help researchers address some of the remaining barriers to large-scale CCS in basalt formations without relying on time-consuming and computationally demanding simulation methods.

Since publishing the paper, Postma has worked on applying his new simulation method to gaining a better understanding of the behavior of the carbon dioxide-water-basalt system during full-scale CCS projects.

Zeng was awarded for his CMI-supported paper, “Possible anthropogenic enhancement of precipitation in the Sahel-Sudan savanna by remote agricultural irrigation,” which was published in the journal Geophysical Research Letters in March. His co-authors included CMI principal investigator Elena Shevliakova, a senior climate modeler at the NOAA Geophysical Fluid Dynamics Laboratory located on Princeton’s Forrestal Campus and a visiting research scholar in HMEI, and Sergey Malyshev, a visiting research collaborator in HMEI.

The paper used an earth-system model to examine the impact of expanded agricultural irrigation on precipitation in remote areas. The researchers found that irrigation in the Middle East and South Asia may enhance rainfall in a large portion of the Sahel-Sudan savanna that spans Africa south of the Sahara Desert. This enhancement arises through a change in the large-scale patterns of atmospheric moisture and temperature that exist from the Sahara to the tropical rainforests of Central Africa.

The study found that rainfall in the savanna was magnified to a similar extent as other human-made climate drivers such as greenhouse emissions suppress precipitation. This means that the expansion of irrigation in far-off regions should be considered as a possible factor affecting the risk of drought and famine in the Sahel-Sudan savanna. In addition, the region’s future water security could be affected by water management and ongoing groundwater depletion in South Asia and by the pace of rehabilitation of the war-damaged irrigation infrastructure in the Tigris-Euphrates valley.