MEDIA RELEASE: R00181 – 29 August 2016
A Brock University geologist is among a group of researchers who believe humans have impacted the Earth in such a significant way that a new time period needs to be added to the planet’s official geologic timeline.
“The message here is that humans have irreversibly changed our planet in a profound way,” says Martin Head, professor in Brock’s Department of Earth Sciences. “Whether we survive as a species or not, we will have left an indelible mark in the geological record.”
Head is part of the Anthropocene Working Group (AWG), which presented its findings at a conference in Cape Town, South Africa Monday that the use of atomic bombs, oil, coal, fertilizers and other products have changed the Earth so much that the very working of the planet has altered.
The AWG told the International Geologic Congress that recent sedimentary deposit findings worldwide contain new minerals and rock types formed from human-made materials. This makes them part of an epoch, or period of time, distinct from the current Holocene period.
Head and the AWG says the new epoch, known as the Anthropocene, begins around 1950. The scientists are suggesting a mid-20th century timing for the proposed “golden spike,” an internationally agreed-upon reference point in a section of sediment layers that signals the beginning of a new episode on the geologic time scale. In past epochs, spikes have come about following natural disasters such as asteroid collisions or a series of volcanic eruptions.
“The rise of plutonium 239 in the early 1950s seems to give the best global signal,” says Head, Chair of the AWG’s parent body, the International Subcommission on Quaternary Stratigraphy. “It arises from increasing aboveground nuclear weapons testing at this time. It declined in the early 1960s with the Partial Test Ban Treaty in 1963.”
In addition to plutonium from atomic bombs detonated during the 1940s and 1950s, contaminants from fossil fuel combustion shot up in all areas of the globe around 1950. Likewise polychlorinated biphenyls (PCBs) and other pollutants from fertilizer production.
A statement released Monday lists a range of recent changes to the Earth, including “marked acceleration to rates of erosion and sedimentation, large-scale chemical perturbations to the cycles of carbon, nitrogen, phosphorus and other elements, the inception of significant change to global climate and sea level, and biotic changes such as unprecedented levels of species invasions across the Earth.
In its statement, released through the University of Leicester, the group says things like plastic, aluminium and concrete particles, artificial radionuclides and changes to carbon and nitrogen isotope pattern will leave a permanent record in the Earth’s strata.
Head says it may take up to three years before the Anthropocene Working Group finalizes its proposal, which it will then present to the International Commission on Stratigraphy (ICS) for a vote on whether or not to include the Anthropocene on the world’s official geologic time scale.
According to the current timescale, Earth is in the Holocene epoch, which began 11,700 years ago after the last major ice age. The Anthropocene, if accepted, will terminate the Holocene as of the mid-20th century.
Read more about the AWG proposal in The Brock News.
Head is currently in South Africa, which is seven hours ahead of Eastern Standard Time. He can be reached directly at mhead@brocku.ca
For more information or for assistance arranging interviews:
* Cathy Majtenyi, Research Communications/Media Relations Specialist, cmajtenyi@brocku.ca, 905-688-5550 x5789 or 905-321-0566
* Dan Dakin, Media Relations Officer, Brock University ddakin@brocku.ca, 905-688-5550 x5353 or 905-347-1970
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