What can we learn about the Earth’s response to anthropogenic forcing from geological records of natural perturbations to the carbon cycle?

There are many lines of evidence in the geological record that point to massive major natural rapid perturbations to the cycles of carbon and other elements. These represent our only direct evidence of the long term repsonse of the Earth system to climate forcing. It is therefore of great importance to understand how these events compare and contrast in rate and scale with our own carbon cycle modifications to better understand the feedbacks, long term consequences and recovery of the Earth system. For instance it is only now that literature is beggining to appear linking de-oxygentation of the oceans to modern climate change. However, many of the geological events are associated with evidence of widespread ocean anoxia and their study can give us some insight into the factors controlling the distribution in time and space of these low oxygen waters.