Carbonate Record of Past Thresholds, Critical Transitions and State Shifts in the Earth Systems

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Many fear that human activities are rapidly pushing our planet's biosphere and ecosystems towards an alternate state from which it will be impossible to go back. While no one can predict when the next state shift will occur, how fast the planet will tip into an alternate state, and what kind of world awaits us beyond the shift, the geological record provides some answers to these questions as the Earth has more than once undergone state shifts of global magnitude. The largest shifts were arguably the major mass extinctions that marked our geological past, and none were more devastating than the Latest Permian Extinction, 252 million years ago. In a scenario that many authors see as the harbinger of horrific things to come if we keep burning fossil fuel, more than 92% of living creatures disappeared from planet Earth over a short period of time. The Siberian Traps eruptions, the largest volcanic eruptions to ever occur, are increasingly fingered as a major cause of the global devastation from which it took Earth 5 million years to recover. However, it is also known that the Earth Systems crossed a series of irreversible thresholds over a 60 million year interval leading-up to that shift resulting in critical transitions that are especially well recorded in carbonate sediments. These are short-lived intervals of major change that took place some 310, 299, 293, 272, 262 and 252 million years ago. We here propose to examine these critical transitions through the study of the marine carbonate system, which was, as it is now, under increasing stress due to an increase in atmospheric carbon dioxide. This will best addressed in comparing and contrasting the critical transitions across widely separated localities. Thirteen students will be involved in various projects that wil be staged in Arctic Canada, Western USA, Europe and the Middle East. These areas used to exist along the western and eastern margins of the supercontinent Pangea, well before the onset of continental drift that led to the present continent configuration. All projects have a field component where students will be measuring and sampling detailed stratigraphic sections and a laboratory component where they will be acquiring additional microscopic and chemical data. Looking into the oceanic deterioration in the distant past is highly relevant to the modern climate change issue, especially considering that the composition and chemistry of the oceans was at that time similar to that of the modern oceans. Our research, while looking into the distant geological past, could generate credible predictions about how the world will change in the future in response to human activities.