IPCC climate change models portray gradual rises in temperature and related consequences through the current and following centuries. By contrast paleoclimate studies indicate the evolution of the atmosphere includes gradual changes as well as abrupt shifts in state of the climate, including tipping points representing a synergy of oceanic feedback processes triggered by solar pulsations and/or sharp rises in atmospheric greenhouse gas levels. Examples of such shifts include inter-stadial warming episodes, i.e. Oeschger - Dansgaard events during the last glacial period, and stadial freezing events such as the Youngest dryas. The underlying factors, scale and timing of these events bear critical implications for projections of future climate changes induced by the current rise of greenhouse gas levels, and for adaptation plans. The current greenhouse gas rise rate exceeding 2 ppm CO2/year is likely to lead to transient stadial event. i.e. collapse of the North Atlantic Thermohaline Current, followed by further rise in extreme weather events, threatening species and civilization.
About the speaker
Dr Andrew Glikson graduated at the University of Western Australia. He conducted geological surveys of the oldest geological formations in Australia, South Africa, India and Canada, studied large asteroid impacts, including effects on the atmosphere and oceans mass extinction of species. Since 2005 he studied the relations between climate and human evolution.