Dr. Lemos began her career as a Visiting Scholar for five years after her Ph.D. at MIT at the Udall Center for Studies in Public Policy at the University of Arizona. Dr. Lemos holds the title of Senior Policy Scholar at the center, which she has held since 2000. During this period, Dr. Lemos was a visiting professor at Columbia University in Oracle, Arizona, during the Biosphere II Earth Semester. Along with this, while at the Udall Center for Studies in Public Policy, Dr. Lemos was also a Post-Doctoral Fellow at the Latin American Area Center at the University of Arizona, a position she held for two years. From 1998 to 2002, Dr. Lemos was also an Adjunct Professor in the Department of Architecture and Planning at the University of Arizona. After her Post-Doctoral Fellowship, Dr. Lemos held the position of Assistant Research Professor of Latin American Studies for 4 years and then transitioned into an Assistant Professor of Latin American Studies. From 1999 to 2001, Dr. Lemos was also a Faculty Fellow on the Global Environmental Assessment Project at the John F. Kennedy School of Government at Harvard University.

After her time in Arizona, Dr. Lemos moved to Michigan, where she took a position with the University of Michigan School for Environment and Sustainability as a Faculty Associate. Dr. Lemos worked in this position for one year before she took a tenure track position as an Assistant Professor of Natural Resources and Environment. After four years, Dr. Lemos was promoted to Associate Professor, and then six years later, received a full Professorship. Dr. Lemos, along with still being a Professor, is currently the Associate Dean for Research and Engagement. During this period, Dr. Lemos was a James Martin 21st Century School Fellow at the Environmental Change Institute at Oxford University.

Dr. Lemos has received many prestigious fellowships and grants, such as the Kalvi Fellow from the US National Academy of Sciences, the National Science Foundation Distinguished Lecture, the Governor's Award for Environmental Excellence in Indiana from the US Department of Agriculture, and the MacArthur Program in Transnational Security Summer Research Grant. Dr. Lemos has authored dozens of peer-reviewed papers since 1998 and national and synthesis reports such as those of the National Research Council and a lead author of the Intergovernmental Panel on Climate Change (IPCC) on the Climate Resilient Pathways Chapter. Dr. Lemos currently sits on advisory boards such as the Environmental Research and Education with the National Science Foundation, the Socio-Environmental Synthesis Center, the University of Leeds, the Federal Committee on Sustained Climate Assessment, and the Research Application Laboratory with the National Center for Atmospheric Research.