A native of Halifax, Canada, Galbraith completed an undergraduate degree in Earth and Planetary Science at McGill University in 1997. He then worked as an exploration geologist in Peru, a journalist, and on polar expedition cruises before undertaking a PhD in Oceanography at the University of British Columbia, completed in 2006. This was followed by three years of postdoctoral research at Princeton University, developing and using Earth System models. Galbraith worked at McGill University as an assistant professor in Earth System Science from 2009-2015, and as full professor and Canada Research Chair in Human-Earth System Dynamics from 2019-2025. He was with ICREA at ICTA, at the Universitat Autònoma de Barcelona (ICTA-UAB), from 2015-2019 and returned in 2025.

Over the past century, humans have emerged as a dominant component of the Earth system. Yet, there are few scientific attempts to address the human and non-human parts of our planet within a unified framework. I use data analysis, mathematical models, and theory to better understand and predict the coupled human-Earth system. My current work includes quantifying global human activities through time use, exploring the dynamics of the global technosphere (all non-living human creations) including material and energy flows, and understanding metrics for human wellbeing—all building toward an approach I call Earth System Economics.