Ancient marine fossils that were used to study previous global warming events
Ancient marine fossils reveal how rising sea levels stored carbon in the oceans, preventing global warming at extinction level 14 million years ago
- Fossil data indicate that a lot of carbon has been caught in the sediment of the ocean
- Substantial volcanic activity had previously led to extinction events
- 14 million years ago, however, the oceans were full of life during global warming
- The researchers say the captured carbon has helped reduce the extinction threat
Ancient marine fossils led scientists to discover that rising sea levels helped prevent global warming 14 million years ago.
Researchers at Cardiff University have studied the fossils of the last known large period of warming up, when the temperature rose by 9 Fahrenheit.
During this period, known as the middle Miocene Climate Optimal, there was an increased volcanic activity that caused the warming.
Instead of causing massive extinction, the seas were full of life – something that, according to the Cardiff team, stunned geologists.
The team says their findings suggest that the worst effects were mitigated by rising sea levels caused by higher global temperatures that retained carbon in the oceans.
Ancient marine fossils led scientists to discover that rising sea levels helped to prevent global warming 14 million years ago
In the period between 14 and 17 million years ago, the position of the continents was similar to today and the seas flourished with life.
The temperature rise of 9F is also comparable to the expected rise in 2100 if there is no change in carbon emissions.
Cardiff researchers said that a significant oil-rich rock, known as the Monterey formation, lay along the California coastline due to the burial of carbon-rich marine life.
“Our planet has been warm before,” said Carrie Lear, senior scientist in the study.
“We can use old fossils to help understand how the climate system works in these times.”
Professor Lear and her team used the chemistry of marine fossils from long sediment cores from the Pacific, Atlantic, and Indian Ocean to control sea temperature and carbon levels.
They discovered that massive volcanic eruptions from the Columbia River flood basalts released CO2 into the atmosphere and caused a pH drop in the ocean.
“With the global temperature as a result, sea levels also rose, flooding large parts of the continents,” said Professor Lear.
This created the ideal conditions for burying large amounts of carbon from the accumulations of marine organisms in sediments.
It also helped to transfer volcanic carbon from the atmosphere to the ocean for tens of thousands of years.
“The increased productivity of the sea and carbon burials helped to remove some of the carbon dioxide from the volcanoes,” said lead author Sindia Sosdian.
“This acted as a negative feedback, mitigating some, but not all, of the climate effects associated with volcanic CO2 emissions.”
Lead author Sindia Sosdian said that slow carbon emissions have minimized the extent of environmental changes 14 million years ago, but that is not something we can count on in the future because the climate is warming up ‘much faster’
Past major episodes of volcanism in Earth’s history have been associated with massive extinctions and widespread lack of oxygen in the oceans, Dr. Said said. Sosdian.
“There was no such event in the middle Miocene Climate Optimum.”
The presence of the Antarctic ice sheet and the relatively slow release of carbon minimized the extent of environmental changes, she said.
“Thanks to our findings, we now have a very clear picture of what was happening more than 14 million years ago and this will change the way scientists look at this period of global warming.
“We know that our current climate is warming up much faster than the Miocene Climatic Optimum, so we will not be able to rely on this slow natural feedback to combat global warming.
“This research is still important because it helps us understand how our planet works when it is in a warm mode.”
The study is published today in the journal Nature communication.
WHAT DOES IT PREDICT FOR THE LOT OF PLANET PLANTS AND ANIMALS?
Nature now has more problems than ever before in human history, with extinction looming over a million species of plants and animals, experts say.
That is the most important finding of the first comprehensive United Nations report on biodiversity – the diversity of plant and animal life in the world or in a particular habitat.
The report – published on May 6, 2019 – says that species are lost dozens or hundreds of times faster than in the past.
Many of the worst effects can be prevented by changing the way we grow food, produce energy, deal with climate change and throw away waste, the report said.
The 39-page summary of the report highlighted five ways in which people reduce biodiversity:
– Forests, grasslands and other areas turn into farms, cities and other developments. The loss of habitat makes plants and animals homeless. Approximately three-quarters of the Earth’s land, two-thirds of the oceans and 85% of the crucial wetlands have been severely altered or lost, making species more difficult to survive, the report said.
– Overfishing of the world’s oceans. A third of the world’s fish stocks are overfished.
– Allowing climate change by burning fossil fuels to make it too hot, wet or dry for some species to survive. Almost half of the land mammals in the world – excluding bats – and nearly a quarter of the birds have already hit their habitats hard by global warming.
– Polluting land and water. Every year, 300 to 400 million tonnes of heavy metals, solvents and toxic sludge are dumped into the world’s waters.
– Allowing invasive species to displace native plants and animals. The number of invasive alien species per country has risen by 70 percent since 1970, with one species of bacteria threatening nearly 400 species of amphibians.