![]() “It is a permanent legacy of human impacts on the planet, written in the rock record,” Waters said. Scientists warn that the planet is getting dangerously close to climate “tipping points,” where ice melt will accelerate and major weather systems could collapse. ![]() Unless the world takes drastic steps to curb global warming, pollution and declines in biodiversity, the situation will become worse, said geologist Colin Waters, chair of the Anthropocene Working Group. Yet advocates for naming the new epoch say Crawford Lake’s sediments make clear the stark contrast between human impacts before 1950 - which were mostly local and often reversible - and the rapid transformation wrought by modernity. “But really, it’s been a long gradient, a long process of changing how we live.” “Formalizing the Anthropocene creates a hard and bright line, and you either exist on one side or the other,” said Jacquelyn Gill, a paleoecologist at the University of Maine. Others have pointed out that - unlike the asteroid impact that killed the dinosaurs and other epoch-defining events - human-caused changes didn’t happen simultaneously all around the world. Some say this period of overwhelming human influence has been too brief to know whether it is truly an epoch, a span that typically lasts millions of years. And not all geologists are convinced the Anthropocene belongs on Earth’s 4.6-billion-year timeline. Crawford Lake is considered a top candidate for the recognition.īefore the Anthropocene - and the lake - can claim a place in geologic history, the proposal must undergo several more rounds of voting. The extraction of this core was one of the last steps before the Anthropocene Working Group selects its preferred “Golden Spike” site, a decision that is expected this summer. “It’s painful, but we recognize that it should be done … because it may help prevent further climate disaster by adding to our understanding of how humans have had an impact on the Earth.” “It’s like a surgical operation,” she said. Dredging up its sediments - even for science - felt like another invasion.īut after hours of reflection alongside representatives from other First Nations, Tammaro had come to agree that the coring should go forward. She calls this space “ Kionywarihwaen” - a Wendat name meaning “where we have a story to tell.”Īnd Crawford Lake had already endured so much painful history. To the Wyandot artist and faithkeeper, who is descended from the people who likely once lived here, the lake is a living being. When the last core samples were taken from Crawford Lake this spring, Catherine Tammaro couldn’t bring herself to watch. The globe as a whole is now warmer than it’s been at almost any point since the end of the last ice age. The lake’s calcite layers became thicker during warm years pollen grains show how the forest composition shifted to include more heat-loving tree species.Īverage temperatures in southern Canada have increased about 1.5 degrees Celsius (2.7 degrees Fahrenheit) in this time. The amount of elm pollen plummeted - a consequence of the invasive fungus that was decimating North America’s tree populations at the time.Īll the while, greenhouse gas pollution made the planet inexorably hotter. Certain microbe species were eliminated locally. Still more sediments recorded irreversible losses. Acid rain, caused by pollution reacting with water in the atmosphere, diminished the calcite layers. The amount of fly ash increased eightfold in less than five years. A lighter form of nitrogen - a molecular signature of burning fossil fuels - proliferated. Other shifts weren’t necessarily new, but they appeared at scales ten or a hundred times greater than anything the lake had seen before. ![]() ![]() The element rarely occurs naturally on this planet it could only have come from nuclear weapon tests happening thousands of miles away. The sharpest sign of change was a surge in radioactive plutonium that started in Crawford Lake’s mud around 1950.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |