Descent into the Ice House
Project website Descent into the Icehouse
Greenhouse
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Icehouse
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PI: Gavin Foster (University of Southampton)
Team: 5 institutions, 6 academics, 4 postdocs, 2 PhD students
Short Introdution of the Project:
For at least as long as the Phanerozoic, the Earth's climate has oscillated between two main modes, a globally warm and humid so-called 'greenhouse state', and periods of significant continental glaciation called an 'icehouse' state. Solid evidence for this grand climatic cycling is relatively scarce and scattered across geological archives of many sorts, becoming ever sparser and more difficult to interpret with increasing age. The relative roles of solar forcing, surface albedo, ocean circulation and greenhouse gas concentrations in controlling the long-term history of surface temperature of the planet are poorly understood, and above all the complex feedbacks exerted by the biosphere in response to global change are only dimly perceived. Reducing these uncertainties has become an urgent priority for Earth system science research given the nature of the uncertainties associated with predicting our future warm climate. This presentation will outline a recently funded proposal by NERC as part of the Life and the Planet theme that focuses on the most recent and best documented major climatic shift on Earth - the Cenozoic climate transition. Understanding of this transition has increased greatly in recent years, stimulated by vigorous debate, providing a platform for new research to better understand the interplay between the physical and biological components in the evolution of the Earth’s climate.
The primary objective of the proposal “Descent into the Icehouse” is to determine what led to the rapid switch at the Eocene/Oligocene boundary from the warm greenhouse state that characterised much of the Mesozoic and early Cenozoic, to the relatively frigid icehouse state that has characterised the last ~34 mys. Although the rapid growth of the Antarctic Ice sheet at ~34 Ma was a threshold event, this was the culmination of a cooling trend that began ~16 million yrs before. The most commonly cited driver of this long-term climate change is a gradual decline in the CO2 concentration of the atmosphere due to a subtle imbalance between silicate weathering (CO2 sink) and volcanic outgassing (CO2 source). Our current proxy records, however, do not support this assertion, suggesting either that factors other than CO2 control long term climate change or that our records of CO2 in early Cenozoic are inaccurate.
Our proposal aims to address the following fundamental questions:
1. What drives the evolution of climate on geological timescales?
2. What role do biological feedbacks have on the evolution of pCO2, and hence climate, on these timescales?
Team: 5 institutions, 6 academics, 4 postdocs, 2 PhD students
Short Introdution of the Project:
For at least as long as the Phanerozoic, the Earth's climate has oscillated between two main modes, a globally warm and humid so-called 'greenhouse state', and periods of significant continental glaciation called an 'icehouse' state. Solid evidence for this grand climatic cycling is relatively scarce and scattered across geological archives of many sorts, becoming ever sparser and more difficult to interpret with increasing age. The relative roles of solar forcing, surface albedo, ocean circulation and greenhouse gas concentrations in controlling the long-term history of surface temperature of the planet are poorly understood, and above all the complex feedbacks exerted by the biosphere in response to global change are only dimly perceived. Reducing these uncertainties has become an urgent priority for Earth system science research given the nature of the uncertainties associated with predicting our future warm climate. This presentation will outline a recently funded proposal by NERC as part of the Life and the Planet theme that focuses on the most recent and best documented major climatic shift on Earth - the Cenozoic climate transition. Understanding of this transition has increased greatly in recent years, stimulated by vigorous debate, providing a platform for new research to better understand the interplay between the physical and biological components in the evolution of the Earth’s climate.
The primary objective of the proposal “Descent into the Icehouse” is to determine what led to the rapid switch at the Eocene/Oligocene boundary from the warm greenhouse state that characterised much of the Mesozoic and early Cenozoic, to the relatively frigid icehouse state that has characterised the last ~34 mys. Although the rapid growth of the Antarctic Ice sheet at ~34 Ma was a threshold event, this was the culmination of a cooling trend that began ~16 million yrs before. The most commonly cited driver of this long-term climate change is a gradual decline in the CO2 concentration of the atmosphere due to a subtle imbalance between silicate weathering (CO2 sink) and volcanic outgassing (CO2 source). Our current proxy records, however, do not support this assertion, suggesting either that factors other than CO2 control long term climate change or that our records of CO2 in early Cenozoic are inaccurate.
Our proposal aims to address the following fundamental questions:
1. What drives the evolution of climate on geological timescales?
2. What role do biological feedbacks have on the evolution of pCO2, and hence climate, on these timescales?