Icebergs in Antarctica are gradually melting farther and farther away from the frozen continent, could be the trigger that plunges the earth into a new ice age, the study finds.
Researchers at Cardiff University have reconstructed past climatic conditions and identified small fragments of the Antarctic rock that fall into the open ocean as part of a study designed to understand how the ice age begins.
Ice age cycles over the past 1.6 million years have been followed by periodic changes to the earth’s orbit of the sun – which change how much solar radiation reaches the surface.
Prior to this study, however, little was known about how changes in solar energy due to small changes in orbit could change the Earth’s climate so dramatically.
They found that melting icebergs gradually moved fresh water from the Southern to the Atlantic Ocean by melting further away from Antarctica – causing a change in ocean circulation and plunging the planet into a cold period – causing an ice age.
Study authors warn that the impact of man-made CO2 emissions could make the Southern Ocean too hot for the Antarctic icebergs, which begin melting icebergs at the end of this 1.6 million-year ice age .
Icebergs in Antarctica that are gradually melting further and further away from the frozen continent could be the trigger that plunges the earth into a new ice age, the study finds. Stock image
The team found that icebergs from the Antarctic gradually melt further north during certain changes in the earth’s orbit around the sun, which reduces the solar power to the surface.
In their study, the team suggests that when the Earth’s orbit around the sun is just right, Antarctic icebergs begin to melt further and further from Antarctica.
As a result, large amounts of fresh water are being moved from the Southern Ocean to the Atlantic Ocean.
As the Southern Ocean becomes saltier and the North Atlantic island becomes fresher, large-scale circulation patterns begin to change dramatically by removing CO2 from the atmosphere and reducing the so-called greenhouse effect.
According to the team, the earth once again pushed the earth into ice age conditions, which rebuilt the climatic conditions in the past, including finding small fragments of the Antarctic rock that fell into the open ocean through the melting icebergs.
The rock fragments were obtained from sediments recovered by the International Ocean Discovery Program (IODP) which represents 1.6 million years of history.
The study found that these deposits, known as Ice-Rafted Debris, apparently consistently lead to changes in deep ocean circulation, reconstructed from the chemistry of small deep-sea fossils called foraminifera.
The team identified small fragments of the Antarctic rock that were deposited in the open ocean by melting icebergs to detect the changes in salt and fresh water over time.
The team also used new symptoms of climate models to test their hypothesis, and found that large amounts of fresh water could move through the icebergs.
Lead author of the study, Aidan Starr, said they were surprised to find that the link between iceberg melting and ocean circulation has been present during each ice age for the past 1.6 million years.
“There has been speculation about such a leading role for the Southern Ocean and Antarctica in the world climate, but it was very exciting to see it clearly in geological evidence,” he said.
Professor Ian Hall, co-author of the study and co-lead scientist of the IODP expedition, from Cardiff, said the results provided a ‘missing link’ in the history of the ice age.
Icebergs from Antarctica move into the southern ocean without melting and shift fresh water from the ocean to the Atlantic Ocean, causing ocean circulation and cooler periods
Over the past three million years, the earth has regularly plunged into ice age conditions, but is currently located in an interglacial period where temperatures are warmer.
However, it may not happen the same way again, due to the impact of human CO2 emissions warming the world.
Researchers suggest disrupting the natural rhythm of ice age cycles, as the Southern Ocean is likely to become too hot for the Antarctic icebergs to move far enough to cause the changes in ocean circulation needed for an ice age to begin.
Professor Hall believes that the results can be used to understand how our climate may respond to anthropogenic climate change in the future.
“Just as we are seeing an increase in the mass loss of the Antarctic continent and the iceberg activity in the Southern Ocean, as a result of the warming associated with the current human greenhouse gas emissions,” Hall said.
“Our study highlights the importance of understanding iceberg orbits and melting patterns in developing the strongest predictions of their future impact on the circulation and climate of the ocean,” he said.
Professor Grant Bigg of the Department of Geography at the University of Sheffield, who contributed to the symbols of the iceberg models, said they are groundbreaking models in climate models.
Its addition was crucial to the ‘identification and support of the hypothesis of the Antarctic ice-floating ice floating waste that is the beginning of the glacier cycle.’
The findings were published in the journal Nature.
ATLANTIC OCEAN CIRCULATION PLAYS A KEY ROLE IN REGULATING THE GENERAL CLIMATE
In terms of global climate regulation, the circulation of the Atlantic Ocean plays a key role.
This is due to a constantly moving system of deep water circulation often called the Global Ocean Conveyor Belt, which sends warm, salty Gulf Stream water to the North Atlantic Ocean where it releases heat into the atmosphere and warms Western Europe.
The cooler water then sinks to deep depths and moves as far as Antarctica and eventually circulates again as far as the Gulf Stream.
In terms of global climate regulation, the circulation of the Atlantic Ocean plays a key role
This movement is fueled by thermohaline currents – a combination of temperature and salt.
It takes 1000 years before water completes an ongoing journey through the world.
Researchers believe that freshwater disrupted the system, called the Atlantic Meridional Overturning Circulation (AMOC), when the North Atlantic Ocean began warming near the end of the Little Ice Age.
Arctic sea ice, and ice sheets and glaciers around the Arctic began to melt, forming a large natural tap of fresh water flowing into the North Atlantic Ocean.
This large inflow of fresh water has diluted the surface seawater, making it lighter and sinking less deeply, slowing down the AMOC system.
Researchers have found that the AMOC has weakened faster since 1950 in response to recent global warming.