Sian Kou-Giesbrecht

Assistant Professor

Phone:  +1 902 431 9277
Mailing Address: 
Dalhousie University
6287 Alumni Cres
PO BOX 15000
Halifax NS B3H 4R2
Life Sciences Centre
4th floor, Ocean Wing
Rm. 4613
Research Topics:
  • Terrestrial Ecosystems and Biogeochemistry
  • Carbon and Nitrogen Cycling
  • Climate Change
  • Earth System Modelling


MA, MPhil, PhD, Columbia University, 2021
BSc, McGill University, 2016


My research explores the impacts of global change on terrestrial ecosystems, nutrient cycling, and the terrestrial carbon (C) sink and ultimately their feedbacks to climate change. I employ an interdisciplinary approach by scaling empirical ecology to Earth system models (ESMs). My research seeks to both enhance our fundamental understanding of terrestrial ecosystems empirically and improve terrestrial biosphere models (TBMs), which are used within the framework of ESMs to project climate change and inform climate change policy by the Intergovernmental Panel on Climate Change (IPCC).
The terrestrial C sink currently sequesters a quarter of anthropogenic CO2 emissions in vegetation and soil biomass, thereby exerting a pivotal control on atmospheric CO2 levels and climate change. However, the terrestrial C sink requires nutrients such as nitrogen to fuel C sequestration because nutrients form the building blocks of organisms alongside C. A major challenge has been resolving the degree to which nutrients will constrain C sequestration under global change, especially as elevated atmospheric CO2 levels stimulate photosynthesis and correspondingly increase nutrient demand (“CO2 fertilisation”). My research addresses the overarching question: To what extent will nutrients limit the terrestrial C sink under global change, and how does this feed back to climate change? Essentially, will the terrestrial C sink continue to sequester a quarter of anthropogenic CO2 emissions, or will this fraction increase or decrease given nutrient limitation?