The excess carbon dioxide emitted by human activity since the start of the industrial revolution has already raised the Earth’s temperature by more than one degree Celsius, increased the risk of extreme hurricanes and wildfires and killed off more than half of the corals in the Great Barrier Reef. But geologic history shows that the impacts of greenhouse gases could be much worse.
In fact, scientists from Scotland’s University of Saint Andrews and two major German research centers have for the first time determined a « conclusive picture » of the initial trigger and subsequent processes responsible for Earth’s biggest mass extinction. The answer? Massive amounts of carbon dioxide spewed into the atmosphere from a volcanic eruption.
« We are dealing with a cascading catastrophe in which the rise of CO2 in the atmosphere set off a chain of events that successively extinguished almost all life in the seas, » study lead author Dr. Hana Jurikova told The Independent.
The study, published in Nature Geoscience Monday, sought to understand the mechanisms behind an event known as the « Great Dying, » the University of Saint Andrews explained in a press release. This was a period around 252 million years ago between the Permian and Triassic epochs in which 95 percent of marine species were wiped out within tens of thousands of years. It is the closest life on Earth has come to total extinction.
Scientists have advanced many theories for what caused this turn of events, including a release of methane from the seafloor and volcanic activity, but this is the first time a group has determined the exact cause, the GEOMAR Helmholtz Centre for Ocean Research Kiel, one of the research centers involved in the new study, said.
« It took several hundreds of thousands to millions of years for the ecosystem to recover from the catastrophe, which profoundly altered the course of evolution of life on Earth, » Jurikova said.
The researchers, who also included members of the Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, were able to reach their conclusions by examining the shells of fossil brachiopods.
« These are clam-like organisms that have existed on Earth for more than 500 million years, » Jurikova explained in the GEOMAR press release.
The researchers were able to assess the pH levels in the ocean based on the different isotopes of boron in the fossilized shells. Because oceanic pH levels are tightly linked to atmospheric carbon dioxide, the team could then create a model of the atmosphere at the time.
« With this technique, we can not only reconstruct the evolution of the atmospheric CO2 concentrations, but also clearly trace it back to volcanic activity, » study coauthor Dr. Marcus Gutjahr of GEOMAR said in the press release.
The amount of carbon dioxide released by the Siberian volcano was more than 40 times all the carbon dioxide currently held in fossil fuel reserves, including everything that has been released since the start of the industrial revolution, according to Saint Andrews.
Still, the researchers told The Independent that the study offered « bleak lessons » for humanity as we face the sixth mass extinction.
« Ancient volcanic eruptions of this kind are not directly comparable to anthropogenic carbon emissions, and in fact all modern fossil fuel reserves are far too insufficient to release as much CO2 over hundreds of years, let alone thousands of years as was released 252 million years ago, » Jurikova told The Independent. « But it is astonishing that humanity’s CO2 emission rate is currently fourteen times higher than the annual emission rate at the time that marked the greatest biological catastrophe in Earth’s history. »
In 1999 a cheering crowd watched as a backhoe breached a hydroelectric dam on Maine’s Kennebec River. The effort to help restore native fish populations and the river’s health was hailed as a success and ignited a nationwide movement that spurred 1,200 dam removals in two decades.
Transmission lines from the Churchill Falls generating station in Labrador. Douglas Spott / CC BY-NC 2.0
Atlantic sturgeon were brought to the brink of extension in the 20th century and are now are listed as an endangered species. NOAA
Near Happy Valley-Goose Bay on the Churchill (Grand) River downstream from Muskrat Falls. Douglas Sprott / CC BY-NC 2.0
Construction of the Site C dam in British Columbia in 2017. Jason Woodhead / CC BY 2.0
The Block Island Wind Farm off the coast of Rhode Island is the first U.S. offshore wind farm. Dennis Schroeder / NREL / CC BY-NC-ND 2.0
Europe is in a panic over the second wave of COVID-19, with infection rates sky-rocketing and GDP plummeting. Belgium has just announced it will no longer test asymptomatic people, even if they’ve been in contact with someone who has the disease, because the backlog in processing is overwhelming. Other European countries are also struggling to keep up testing and tracing.
Meanwhile in a small cabin in Helsinki airport, for his preferred payment of a morsel of cat food, rescue dog Kossi needs just a few seconds to tell whether someone has coronavirus.
An annual comprehensive report on air pollution showed that it was responsible for 6.67 million deaths worldwide, including the premature death of 500,000 babies, with the worst health outcomes occurring in the developing world, according to the State of Global Air, which was released Wednesday.
If you’ve been considering throwing out that old couch, now might be a good time. Dust in buildings with older furniture is more likely to contain a suite of compounds that impact our health, according to new research.
Earth, Permian–Triassic extinction event, Permian, Climate change
World news – CA – CO2 Emissions Caused Earthâs Largest Mass Extinction, Study Confirms