![]() Geologically, this boundary also marks Earth's last globally synchronous cool moment before the onset of the long-term global warmth of the Anthropocene." Many historians regard agricultural imports into Europe from the vast new lands of the Americas, alongside the availability of coal, as the two essential precursors of the Industrial Revolution, which in turn unleashed further waves of global environmental changes. He added: "Historically, the collision of the Old and New Worlds marks the beginning of the modern world. ![]() We humans are now a geological power in our own right - as Earth-changing as a meteorite strike." The Anthropocene probably began when species jumped continents, starting when the Old World met the New. Today we can say when those changes began and why. They will be in no doubt that these global changes to Earth were caused by their own species. Lead author, Dr Simon Lewis (UCL Geography and University of Leeds), said: "In a hundred thousand years scientists will look at the environmental record and know something remarkable happened in the second half of the second millennium. ![]() ![]() They chose the Latin word for 'world' because this golden spike was caused by once-disconnected peoples becoming globally linked. The researchers have named the 1610 dip in carbon dioxide the 'Orbis Spike'. Thus, the second requirement of a golden spike marker is met. The abrupt near-cessation of farming across the continent and the subsequent re-growth of Latin American forests and other vegetation removed enough carbon dioxide from the atmosphere to produce a drop in CO2. Colonisation of the New World led to the deaths of about 50 million indigenous people, most within a few decades of the 16th century due to smallpox. The drop occurred as a direct result of the arrival of Europeans in the Americas. The researchers also found a golden spike that can be dated to the same time: a pronounced dip in atmospheric carbon dioxide centred on 1610 and captured in Antarctic ice-core records (1). This irreversible exchange of species satisfies the first criteria for dating an epoch - long-term changes to Earth. The first fossil pollen of maize, a Latin American species, appears in marine sediment in Europe in 1600, becoming common over subsequent centuries. They argue that the joining of the two hemispheres is an unambiguous event after which the impacts of human activity became global and set Earth on a new trajectory. This rapid, repeated, cross-ocean exchange of species is without precedent in Earth's history. The scientists say the 1492 arrival of Europeans in the Americas, and subsequent global trade, moved species to new continents and oceans, resulting in a global re-ordering of life on Earth. The researchers conclude that 1610 is the stronger candidate. Just two dates met the criteria: 1610, when the collision of the New and Old Worlds a century earlier was first felt globally and 1964, associated with the fallout from nuclear weapons tests. The study authors systematically compared the major environmental impacts of human activity over the past 50,000 years against these two formal requirements. Such a marker - like the chemical signature left by the meteorite strike that wiped out the dinosaurs - is called a golden spike. Scientists must also pinpoint and date a global environmental change that has been captured in natural material, such as rocks, ancient ice or sediment from the ocean floor. Long-lasting changes to the Earth must be documented. Scientists at UCL have concluded that humans have become a geological power and suggest that human actions have produced a new geological epoch.ĭefining an epoch requires two main criteria to be met. Human actions are now changing the planet, but are we really a geological force of nature driving Earth into a new epoch that will last millions of years? Previous epochs began and ended due to factors including meteorite strikes, sustained volcanic eruptions and the shifting of the continents.
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