When did the Anthropocene really start?

Invasive species introduced by humans to new regions could also be markers, scientists say. The unintentional importation of alien species in the ballast water of ships arriving in San Francisco from Asia has changed the San Francisco Bay. “There was a point where 98 percent of the mass of all animal species in the bay were actually invasive,” Waters said. Pollen from introduced plant species, such as trees used in commercial forestry, can also register changes.

Chemical and metal contamination also shows up in deposits, Turner said: Green revolution was based on artificial fertilizers and pesticides, and you see it in sediment cores. The whole cocktail of industrial chemicals just exploded after the war.” Whether chemicals persist in the environment long enough to be markers of the Anthropocene remains to be determined.

All 12 potential sites for the site that will define a new era have some markers, but they are very different. “Because the Anthropocene hasn’t been formally accepted, we’re still trying to prove to people that it’s not something localized, it’s something that you find and relate to in a whole range of different environments,” Waters said.

“They all illustrate this dramatic transformation of the Anthropocene very well. But the places that really stand out are the ones where you can really see the annual resolution of the layers,” Turner said, including some patches of lakes, coral and polar ice. “It’s amazing that these sites detail planetary changes with annual resolution.”

All have pros and cons. The 32-meter-long Palmer ice core from the Antarctic Peninsula is the longest record of the Anthropocene, but its remoteness means traces of some markers are often faint. With the onset of the Anthropocene, the Baltic Sea sediments change color from pale to black. This is caused by an algae bloom caused by pollution sucking all the oxygen out of the water. But the deposits do not have annual layering. Archaeological excavations in the center of Vienna yield a 200-year-old artifact-dated record, but there are gaps in the record due to reconstruction.

The choice of site, and therefore the official time and place of dawn of the Anthropocene, is in the hands of the 23 voting members of the AWG, but must then be approved. Subcommittee on Quaternary Stratigraphythen International Commission on Stratigraphyand finally be ratified International Union of Geological Sciences. There is also a deadline: International Geological Congress in South Korea in 2024, when the term of the AWG expires. “It was stated that until then we should do it,” Waters said.

Naomi Oreskes, a professor at Harvard University and a non-voting member of the AWG, said: “As geologists, we have been trained to think that humans are insignificant. It used to be true, but it’s no longer true. The evidence collected by the AWG demonstrates beyond doubt that the human footprint is now visible in rocks and sediments. The Anthropocene is primarily a scientific concept, but it also highlights the cultural, political, and economic consequences of our actions.”

Mark Maslin of UCL, co-author planet of people with Simon Lewis, said, “I think the Anthropocene is a critical philosophical term because it allows you to think about what kind of impact we’re having and what impact we want to have in the future.”

Maslin and Lewis earlier suggested 1610 as the beginning of the Anthropocene, reflecting the vast and deadly influence of European colonists on the Americas and therefore the entire world. But Maslin said agreeing on a definition is more important than pinpointing its exact location.

“Until now, we have been talking about things like climate change, the biodiversity crisis and the pollution crisis as separate things,” he said. “The key concept of the Anthropocene is to put it all together and say that humans have a huge impact on the Earth, we are the new geological superpower. This holistic approach allows you to say, “What are we going to do about this?”