Anthropocene: Scientists suggest lake in Canada as landmark – 07/11/2023 – Environment

Scientists suggest that Lake Crawford, in Canada, is considered the point that marks the beginning of the Anthropocene, the epoch of humans. The site, argues a group of researchers, has characteristics that make it a point of reference for understanding the proposed new geological era, characterized by changes on the planet caused by human activity.

The key year would be 1952, when analyzes of the lake’s soil registered traces of nuclear tests, in addition to high industrial activity.

The announcement of the location suggested as the “golden spike”, in the expression used by geologists, was made this Tuesday (11) by researchers from the AWG (acronym in English for the Anthropocene Working Group). The conference, jointly with the Max Planck Society, takes place this afternoon in Berlin.

To become an Anthropocene landmark, however, the lake in Ontario still needs to pass three ballots from other scientific institutions, with at least 60% approval.

Defining the Anthropocene is measuring the depth and extent of human activity on the planet. The topic has gained repercussions along with debates on climate change and energy transition.

The scientists point out that the role of this milestone is to produce the evidence that shows a shift from the Holocene, our current geological epoch, which began about 11,700 years ago, to the epoch of humans.

In addition to the scientific significance of this geological turn of the age, the definition has a symbolic dimension about the course of humanity, as it places the damage caused to Earth at the center of the debate.

The suggestion of Lake Crawford, located within a conservation area of ​​the same name, is the result of more than a decade of work by different groups of scientists, the AWG among them, who researched and discussed 12 locations in different parts of the world, such as coral in Australia, ice in Antarctica and a cave in Italy. The idea was to look for what would be the perfect reference point to compare the stored particles.

Located in the city of Milton, in the province of Ontario, Lake Crawford is of the Meromithic type. This means your water layers don’t mix. It was from the deepest region, about 24 meters from the surface, that the scientists collected soil samples.

The sediments contained in the layers at the bottom of the lake function as an archive of the activities of ancient indigenous communities, colonizers, industries and nuclear tests.

Tests carried out on soil samples from the lake led to the choice of the year 1952 as a milestone for the beginning of the Anthropocene —a term coined by biologist Eugene Stoermer and Nobel Prize-winning chemist Paul Crutzen in 2000. In addition to the high industrial and consumer activity in Perceived global scale in the period, experiments with nuclear bombs spread plutonium, an element that does not occur easily in nature.

Other elements also dispersed through the atmosphere and were deposited at the bottom of the South Atlantic, in Caravelas, Bahia. It was there that researchers took an 80 cm long sample, which revealed concentrations of Cesium-137.

The collection and analyzes are recorded in the documentary “The Era of Humans”, which opens in theaters in September and on the Globoplay platform in October. The production, presented by actor Marcos Palmeira, relates the findings to episodes of environmental degradation, such as fires, deforestation and mining.

The research recorded in the film is conducted by Rubens Figueira, a specialist at USP’s Oceanographic Institute. “The same measurements taken in Canada were taken here in Caravelas with Rubens, and that shows how close this subject is to us”, says Iara Cardoso, director and screenwriter of the documentary.