DESCRIPTION:
Rapid climate change as known from the last few million years can also occur during times of relatively stable climate, such as the warm equable greenhouse climate of the Cretaceous. The terms "icehouse" and "greenhouse" have been used to describe those alternate states of the Earth's climate.The goal of the project is to understand causes of rapid environmental change during times of otherwise stable climate.
These climate oscillations correspond to changes in the Earth's orbital parameters, affecting the amount of radiation received from the sun at different latitudes and amplified by Earth's varying albedo, as ice accumulated or melted, sea level fell and rose, the planet's plant cover changed and the mass of plankton in the oceans varied: effects augmented by small changes in nutrient availability and atmospheric greenhouse gas content.
Large, rapid climate perturbations also occurred during the "greenhouse world" of the Cretaceous. These events were not the direct result of orbital variations, but most likely reflect changes in atmospheric greenhouse gas content forced by tectonics. It is suspected that these episodes of climate change were a result of the sudden injection, into the atmosphere, of methane trapped on the continental margins and in the deep sea. The release of the methane is thought to be in response to gradual warming of the ocean as a result of widespread undersea volcanic activity and tectonic disturbance of the sediments containing the gas.
Building on previous work from IGCP 463 (Upper Cretaceous oceanic red beds: Response to the oceanic/climate change) and IGCP 494 (From black shales to oceanic red beds during Mid-Cretaceous), the project aims to investigate the causes, processes, and consequences of rapid environmental changes in the Cretaceous greenhouse world. In contrast to the oscillating glacial-interglacial climates of the past few million years, the Cretaceous was a time of long-term climate stability with warm equable climates resulting from a higher content of atmospheric greenhouse gases. However, this stable climate was periodically disturbed by short-term episodes of warming and cooling, apparently related to rapidly changing greenhouse gas concentrations. The project will evaluate, in detail, the causes and effects of these perturbations of the otherwise stable system. The results of this investigation will be relevant to understanding potential variations in the Earth's near-term future climate.
A Central European Working Group will be established and yearly field campaigns will be planned together including cooperations of various specialists for marine-terrestrial correlations.

Pressemitteilung der Universität Wien