Taking an Earth history perspective in understanding the controls on atmospheric carbon dioxide

We are addressesing fundamental questions surrounding global environmental change and how the concentration of carbon dioxide in the atmosphere is regulated. The starting point is the geological past. For instance, it is thought that changes in atmospheric CO₂ and 'Greenhouse' warming can help explain why the Earth was subject to glaciation and ice ages during some time periods in the past but sweltered in a 'hot house' during others. If so, what causes CO₂ to vary through geologic time? Of particularly interest are the environmental consequences of 'catastrophic' events when the geological record suggests a massive release of CO₂ took place, perhaps due to the oxidation of methane unlocked from ocean sediments. One such event occurred at the end of an Epoch known as the Paleocene, some 10 million years after the last dinosaur walked on the face of the Earth. Because there was a substantial warming of the Earth's surface at this time as well as severe species extinction in the ocean there may be important lessons to be learnt regarding the consequences of our continued burning of fossil fuels and increasing global warming.

We do not have spare copies of our planet on which to experiment and test ideas about the causes of global change! The research tool is therefore a computer model ('genie') of the Earth system - the suite of interacting physical, chemical, and biological (and human processes) that, in transporting and transforming materials and energy jointly determine climate and the conditions for life. The model will include representations of ocean circulation and atmospheric transport, greenhouse warming, and land and sea ice, as well as all their interactions. Our speciality in this is in the cycling of carbon and nutrients within the ocean and how this interacts with the climate system and with the sedimentary reservoirs of the deep ocean and shallow tropical seas.

last updated October 29, 2004