Research Themes

The ocean's role in long-term climate equilibration

My current work dives into the role of the ocean in pacing the climate's long-term adjustment to contemporary anthropogenic forcing. We find that the time the climate takes to equilibrate to modern-day forcing varies widely (by many hundred years) across different global climate models. These differences drive uncertainty in our best estimates of future global warming across the coming centuries. In this project, we show that the main source of this uncertainty derives from oceanic processes and their effect on ocean heat uptake and release. This work is discussed further in Newsom et al., in prep.

Constraining 21st century climate warming via the Ocean Heat Uptake Efficiency

The ocean plays a central role in setting how quickly, and how much, the climate warms in response to anthropogenic greenhouse gas forcing. This role is quantified by the "Ocean Heat Uptake Efficiency," a metric describing how deeply ocean processes convey heat into the ocean's interior. This metric varies widely across state-of-the-art global climate models, driving uncertainty in projections of 21st century warming. My research works to reduce this uncertainty by linking the Ocean Heat Uptake Efficiency to the a measurable feature of the global ocean called the the "pycnocline". We show that variance in pycnocline depth drives ~70% of the uncertainty in heat uptake efficiency across models, a robust relationship that can be leveraged with observations to constrain future climate change. For more on this topic, see Newsom et al., 2023 and Gregory et al., 2023. For a broader discussion of 21st century ocean heat uptake, see my collaborative work in Cheng et al., 2022.

Impact and drivers of ocean warming patterns

Another aim of my research is to better understand the processes setting, and set by, ocean warming patterns. This includes warming both at the ocean surface and within its deeper layers, where the majority of heat from anthropogenic forcing is stored. For more on this topic, see Newsom et al., 2022 and Newsom et al., 2020.

Global ocean heat transport and overturning across climate states

Another theme of my work is understanding how the large-scale circulation of the ocean, known as the Global Overturning Circulation (GOC), evolves with the climate state and influences climate changes by transporting vast quantities of heat. This work identifies processes that control the GOC and global heat transport and investigates how these controls vary with the climate state. For more discussion on this theme, see Nayak et al., 2024, Newsom et al., 2021, Newsom and Thompson, 2018, and Holmes et al., 2019

Southern Ocean sea ice and circulation in climate

The Southern Ocean plays an outsized role in the global climate system and global ocean dynamics, mediating heat and carbon sequestration and transport across a range of timescales. Another facet of my research concerns the circulation and dynamics of Southern Ocean, and particularly how these dynamics are influenced by Southern Ocean sea ice. For my work in this area, please see Newsom et al., 2016, Abernathey et al., 2016, and Armour et al., 2016.

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