What is the Anthropocene age? Why do scientists think the Earth is in a new era?

A new chapter in Earth’s history has begun. Scientists have said a lake in Canada contains evidence that our planet is entering a new epoch –  the Anthropocene age. “The data show a clear shift from the mid-20th Century, taking Earth’s system beyond the normal bounds of the Holocene," members of the Anthropocene Working Group (AWG) have stated. But what is the Anthropocene Epoch? And what does it mean for the Earth? Let’s take a closer look: What happened? The Earth is currently in the Holocene age – which began 11,700 years ago as the last ice age drew to a close. It is up to the AWG to determine whether the Earth has moved on from the Holocene to the Anthropocene age, according to BBC.

As per CNN, the AWG comprises 35 geologists who have been working on this question since 2009.

The group also proposed a starting date for the Anthropocene age – all the way back to 1950 when the world saw nuclear weapons tests. Members of the Anthropocene Working Group spent years examining a dozen different candidates around the world including another lake, coral reefs, ice cores and an ocean bay in Japan before zeroing in on Lake Crawford in Ontario. The group concluded that layered sediment at the bottom of Lake Crawford – laced with microplastics, fly-ash spread by burning oil and coal, and the detritus of nuclear bomb explosions – is the single best repository of evidence that the Anthropocene age has begun. According to Forbes, Lake Ontario was chosen as the site of the ‘golden spike’ – the place where the start and end of an epoch can be quantified by fossil contents that represent a major global occurrence. “We see these spheroidal carbonaceous particles - ‘fly ash’ - that are produced by the very high-temperature combustion of fossil fuels, primarily coal,” professor Francine McCarthy of Brock University, Ontario, told BBC. “The record at Crawford Lake is representative of the changes that make the time since the mid-20th Century geologically different from before,” McCarthy told Vox. [caption id=“attachment_12859202” align=“alignnone” width=“640”] A team of scientists is recommending the start of a new geological epoch defined by how humans have impacted the Earth should be marked at the pristine Crawford Lake outside Toronto in Canada. AP[/caption] “The data show a clear shift from the mid-20th century, taking Earth’s system beyond the normal bounds of the Holocene”, the epoch that began 11,700 years ago as the last ice age ended, working group member Andy Cundy, a professor at the University of Southampton, told AFP. “The sediment found at the bottom of the Crawford Lake provides an exquisite record of recent environmental change over the last millennia,” said working group chair Simon Turner, a professor at University College London. “Crawford is just brilliant for this,” Turner told BBC. “A core from its bottom muds looks like a massive dirty lollipop, but it contains these beautiful, annually laminated sediments. Those annual layers record fossil fuel combustion products, plutonium, changes in geochemistry, changes in micro-ecology - all the sorts of things that chart environmental change,” “It is this ability to precisely record and store this information as a geological archive that can be matched to historical global environmental changes,” Turner told AFP. Those changes are currently on dramatic display: last week was the hottest globally on record. Out-of-control forest fires have been ravaging Canada for months, while the US and China are coping with unprecedented heat, flooding and drought at the same time. Humanity has burned so much fossil fuel that concentrations of planet-warming CO2, meanwhile, have increased by half. Sea surface temperatures have hit new highs in recent weeks, and Antarctic sea ice last month was 17 percent below the previous record low for June. As Anthropocene Working Group chair Colin Waters told CNN, “When it’s 8 billion people all having an impact on the planet, there’s bound to be a repercussion.” “We’ve moved into this new Earth state and that should be defined by a new geological epoch,” added Waters, an honorary professor at the Geography, Geology and the Environment School at the University of Leicester. ‘Great Acceleration’ Last month scientists reported that so much water has been pumped from underground reservoirs that Earth’s geographic North Pole has shifted – by nearly five centimetres (two inches) per year. According to the rules of the International Commission on Stratigraphy (ICU), there must be a synchronous “primary marker” for a proposed boundary that is detectable in the geological record almost anywhere on the planet.

For the Anthropocene, plutonium cast off by hydrogen bomb tests provides that “global fingerprint”, explained Cundy.

“The clearest marker for a single year – which gives an abrupt and effectively instantaneous snapshot – is plutonium, because there’s so little of it naturally present.” “We see plutonium in sediments and other materials from about 1945 onwards, relating to the atomic weapons testing programme. But really the point at which plutonium deposition went global was following high-yield thermonuclear bomb tests, starting in 1952,” Cundy told BBC. “One of the plutonium isotopes we’re looking at has a half-life of 24,000 years, so it will be visible in the sediments for at least 100,000 years. Beyond that, the SCPs will still be detectable,” Cundy added. That means 1952 – when the United States first detonated a huge hydrogen bomb in the Marshall Islands as a test – could become the Anthropocene’s boundary year, he said. Smaller atom bomb explosions before that left mostly regional imprints. [caption id=“attachment_12859212” align=“alignnone” width=“640”] Ripples are seen in the water of Crawford Lake. AP[/caption] A sharp, hockey-stick increase across a dozen markers of humanity’s growing impact – including population, water use, greenhouse gas emissions, and forest loss – bunched around the middle of the 20th Century add up to what scientists call the Great Acceleration. “At present, we’ve had 70 years of the Anthropocene,” Waters was quoted as saying by DW. “That has been long enough, because of the rapidity of the change and the preciseness of it, to recognise that we’ve moved into this new Earth state, and that it should be defined by a new geological epoch.” “Clearly the biology of the planet has changed abruptly,” Waters said. “We cannot go back to a Holocene state now.” But some remain sceptical The “epoch of humans” first proposed in 2002 by chemistry Nobel Paul Crutzen is widely accepted within science as a reality, but faces daunting hurdles for formal validation by the gatekeepers of Earth’s official geological timeline of eon, eras, periods and epochs, such as the Jurassic and the Cretaceous. The Anthropocene’s recommendations must be approved by super-majority vote of two separate committees before final validation by the International Unions of Geological Sciences (IUGS). According to Forbes, the International Geological Congress is slated to meet in South Korea in 2024. The heads of those bodies have thus far expressed sharp scepticism towards the Anthropocene, mostly on technical grounds. “The vote in the working group is on a routine step at the lowest level,” IUGS general secretary Stanley Finney told AFP. The working group has yet to submit its final recommendation to the International Commission on Stratigraphy, he noted. “Only then can it be given peer review, and the evidence and arguments truly evaluated,” Finney said. With inputs from agencies