Sao Paulo
Scientists suspect that Lake Crawford in Canada is believed to be the point that marks the beginning of the Anthropocene, the epoch of mankind. According to a group of researchers, the site has features that make it a reference point for understanding the projected new geological age, marked by changes on the planet caused by human activity.
The decisive year would be 1952, when analyzes of the seabed revealed traces of nuclear testing, in addition to high industrial activity.
The announcement of the site, dubbed the “golden thorn” (as geologists call it) was announced this Tuesday (11) by researchers at the Anthropocene Working Group (AWG). The conference will take place this afternoon in Berlin together with the Max Planck Society.
However, to become an Anthropocene landmark, the Ontario lake must still pass three votes by other scientific institutions with at least 60% approval.
Defining the Anthropocene means measuring the depth and magnitude of human activity on the planet. The topic has gained importance along with the debates on climate change and the energy transition.
The scientists point out that the role of this milestone is to provide evidence that shows a transition 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 turning point, the definition has a symbolic dimension about the course of mankind, since it puts the damage to the earth at the center of the debate.
The proposal to place Lake Crawford in a nature reserve of the same name is the result of more than a decade of work by various groups of scientists, including the AWG, who have researched and discussed 12 sites in different parts of the world, such as coral in Australia, ice in Antarctica and a cave in Italy. The idea was to search for 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. That means your water layers don’t mix. The scientists collected soil samples from the deepest region, around 24 meters above the surface.
The sediments contained in the strata at the bottom of the lake act as an archive of the activities of ancient indigenous communities, colonizers, industries and nuclear testing.
Tests on soil samples from the lake led to the choice of 1952 as the milestone for the beginning of the Anthropocene a term coined in 2000 by biologist Eugene Stoermer and Nobel laureate Paul Crutzen.
In addition to the high level of industrial activity and global consumption seen during this period, experiments with atomic bombs spread plutonium, an element not readily found in nature.
Other elements also dispersed into the atmosphere and deposited on the bottom of the South Atlantic at Caravelas, Bahia. There, researchers took an 80 cm long sample that showed concentrations of cesium137.
The collection and analysis will be captured in the documentary The Era of Humans, which will be released in theaters in September and on the Globoplay platform in October. Presented by actor Marcos Palmeira, the production relates the results 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 the USP’s Oceanographic Institute. “The same measurements as 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.