Defining the human era – Expert reaction

The world has entered into a new geological era — the Anthropocene — marked by human impact on the environment, according to an international team of scientists.

Hurricane Public domain (not CC, Via NASA)The case for a new epoch was made in an article published in Science, in which the authors detailed the geological and environmental evidence for humans creating a new geological age.

The Anthropocene epoch would be recognised by the spread of material such as aluminium, concrete, plastic and nuclear material, as well as higher levels of greenhouse gases, climate change, species extinctions and a reshaping of coastal sedimentation processes, said co-author Professor Will Steffen from The Australian National University (ANU).

The Anthropocene Working Group will gather more evidence in 2016, which will help contribute to the case for formal recognition of the Anthropocene epoch. A decision will be made by the International Commission for Stratigraphy, which meets in South Africa in September.

NIWA’s Dr Helen Bostock, president of the Australasian Quaternary Association, wrote a blog last year laying out the background to the decision on the new epoch.

Our colleagues at the AusSMC collected the following expert commentary.

Dr Duanne White, Assistant Professor in Earth Systems at the University of Canberra, comments:

“I strongly agree with the sentiments of the paper. While us scientists will probably debate the precise onset of the Anthroprocene for the next decade, sediments across the planet will continue to record our disruptive influence to the Earth System. In eastern Australia the expansion of agriculture in the 1800s provided a stark change to our rivers and creeks, with extensive formation of gullies in the headwaters and silting of the major rivers. All across the country you can go out and see the transition from the Holocene to the Anthroprocene  in our stream banks – from the organic muds of the Holocene at the base, to the sandy inorganic sediments  of the Anthroprocene near the surface. In most cases this transition is as significant and clear as the change from the late Pleistocene (‘ice age’) to the Holocene ‘interglacial’ sediments.”

Professor Will Steffen, Adjunct Professor at the Fenner School of Environment and Society at the Australian National University, and ao-author of the new research, comments:

“The geological data are now abundant and clear – human activities now rival, or in some cases exceed – the great forces of nature that have shaped the evolution of Earth’s environment over its 4.6 billion year existence. The Anthropocene represents a rapid destabilisation of the Earth’s environment compared to the 11,700-year long Holocene epoch, the most recent period of Earth history in which humans have developed agriculture, villages and cities, and the contemporary societies we live in today. The Anthropocene is a planetary wake-up call. We are sailing into planetary terra incognita.