Beyond climate tipping points: the changing face of planet Earth
Speaker: Dr Andrew Glikson
ANU Climate Change Institute
The scale and rate of global warming have been underestimated. Paleoclimate evidence suggests that no event since 56 million years ago, the Paleocene-Eocene Thermal Maximum (PETM), has been as extreme as the atmospheric disruption since the industrial age about 1750 AD, in particular since the mid-20th century. The transfer of hundreds of billions of tonnes of carbon, the toxic residues of ancient biospheres, from the Earth crust to the atmosphere and oceans is leading to an extreme shift in the composition of the atmosphere and ocean at a faster rate Earth experienced in the Cenozoic. Since the industrial revolution about 375 billion tonnes carbon (1,374 billion tonnes CO2) have been emitted by humans into the atmosphere. The consequences include mega-droughts, heat waves, fires, storms and floods. With atmospheric CO2-equivalent (CO2+CH4+N2O) rising above 500 ppm and mean global temperatures by more than +1.5oC to +2.0oC above pre-industrial temperatures, when the transient masking effects of aerosols are taken into account), climate zones are shifting rapidly polar-ward, including the weakening of the Arctic jet stream boundary, expansion of the tropics and sub-tropical deserts is estimated at 56 - 111 km per decade. The probability of a stadial cooling events in parts of the oceans is supported by the development of cold water pools south of Greenland and north of Antarctica and by modelling by Hansen et al. 2016. These developments are associated with droughts, heat waves and fires, hardly compensated by minor greening of inner fringes of the subtropics.
Andrew Y. Glikson, an Earth and paleo-climate scientist, graduated at the University of Western Australia. conducted geological and geochemical surveys of the oldest geological formations in western and central Australia, South Africa, India and Canada, studied large asteroid impacts, including effects on the atmosphere, oceans and mass extinction of species. Since 2005 he studied the relations between climate and human evolution and projections of future global warming based on paleoclimate evidence. He was active in communicating the evidence of the dangers of nuclear and climate change.