Dr. David Kidder, Associate Professor of Geological Sciences at Ohio University, discusses Phanerozoic Hothouse Climates in a Geological Sciences Colloquium on Friday, Jan. 24 at 2 p.m. in Clippinger Laboratories, Room 205.
Dr, David Kidder
Abstract: Hothouse climate has been approached or achieved more than a dozen times in Phanerozoic history. Geologically rapid onset of hothouses in 104–105 yr occurs as HEATT (haline euxinic acidic thermal transgression) episodes, which generally persist for less than 1 million years. Greenhouse climate preconditions conducive to hothouse development allowed large igneous provinces (LIPs), combined with positive feedback amplifiers, to force the Earth to the hothouse climate state. The two most significant Cenozoic LIPs (Columbia River Basalts and much larger Early Oligocene Ethiopian Highlands) failed to trigger a hothouse climate from icehouse preconditions, suggesting that such preconditions can limit the impact of CO2 emissions at the levels and rates of those LIPs. Human burning of fossil fuels can release as much CO2 in centuries as do LIPs over 104–105 yr or longer. Although burning fossil fuels to exhaustion over the next several centuries may not suffice to trigger hothouse conditions, such combustion will probably stimulate enough polar ice melting to tip Earth into a greenhouse climate. Long atmospheric CO2 residence times will maintain that state for tens of thousands of years.
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