Earth’s thermostat: revisiting the controls on the long-term carbon cycle

19 January 2018
Sala d'Actes
Given by: 
Dr. Laurence Coogan
Position at: 
School of Earth and Ocean Sciences, University of Victoria, British Columbia, Canadà


The textbook model of the long-term carbon cycle suggests that increased atmospheric CO2 levels lead to increased surface temperatures and, in turn, to increased rates of continental chemical weathering and hence CO2 draw-down. This negative feedback is thought to have maintained a habitable climate on Earth's for >3.5 Gyr. This talk will question this model and argue that low-temperature alteration of the upper oceanic crust in off-axis hydrothermal systems plays a key role in both the long-term carbon cycle and in controlling ocean chemistry. This model, if correct, has broad implications for understanding the Earth System and Earth history.


Brief biography

My research focussed on the role of the oceanic crust in the Earth system. Specific projects range from understanding mantle melting and melt evolution at mid-ocean ridges, through on-axis "black smoker" hydrothermal systems, to low temperature alteration of the oceanic crust. I use field studies on land (ophiolites) and at sea (including cabled observatory), analytical (geochemical), experimental and modelling studies depending on the question being addressed.