Scientists determine an explosion of Antarctic sea ice may have sent the world into an ice age 2.5 million years ago
- Computer simulations find previous ice ages may have been cause by sea ice
- Sea ice acted as a lid on the ocean, blocking it from releasing carbon dioxide
- Less CO2 in atmosphere creates a reverse greenhouse effect and cool the earth
Scientists have discovered that the world’s ice ages may have been caused by sea ice forming a lid on the ocean and blocking its exchange of carbon dioxide with the atmosphere.
Less carbon dioxide in the atmosphere could result in a reverse greenhouse effect, causing the planet to cool –leading experts to believe that the ice circling the frozen desert may have sparked the ice age 2.5 million years ago.
However, an ice age looks unlikely any time soon, as sea ice is at an all-time low and data shows it could keep declining.
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Scientists studying Antarctica sea ice warn a rise in accumulation could spark an ice age. Computer simulations show that an explosion of sea ice would block the ocean from exchanging carbon dioxide with the atmosphere
The last major ice age is believed to have ended about 2.5 million years ago during the Pleistocene era, according to UChicago News.
Since then, glaciers have periodically covered the earth, but have also retreated, which experts have now set out to understand the process behind an ice age — how it works and what triggers it.
The latest study was conducted by a team at the University of Chicago who set out to discover and understand the processes that makeup global climate.
Assistant professor Malte Jansen at the University of Chicago (UChicago) told UChicago News, ‘One key question in the field is still what caused the Earth to periodically cycle in and out of ice ages.’
‘We are pretty confident that the carbon balance between the atmosphere and ocean must have changed, but we don’t quite know how or why.’
This event is capable of causing a reverse greenhouse effect, which would ultimately cool the earth and send our planet into an ice age for the first time in over two million years
Jansen and former UChicago postdoctoral researcher Alice Marzocchi developed computer simulations of Antarctica sea ice and found it not only changes ocean circulation but acts as a lid and blocks it from releasing carbon dioxide into the atmosphere – the less carbon in the air, the cooler the planet becomes.
‘What this suggests is that it’s a feedback loop,’ said Marzocchi, now a research scientist at the UK’s National Oceanography Center.
‘As the temperature drops, less carbon is released into the atmosphere, which triggers more cooling.’
The explanation does coincide with past climate evidence from things like sediments, coral reefs and core samples from glaciers, the researchers explained.
‘What surprised me is how much of this increased storage can be attributed to physical changes alone, with Antarctic sea-ice cover being the key player,’ Marzocchi said.
HOW MUCH WILL SEA LEVELS RISE IN THE NEXT FEW CENTURIES?
Global sea levels could rise as much as 1.2 metres (4 feet) by 2300 even if we meet the 2015 Paris climate goals, scientists have warned.
The long-term change will be driven by a thaw of ice from Greenland to Antarctica that is set to re-draw global coastlines.
Sea level rise threatens cities from Shanghai to London, to low-lying swathes of Florida or Bangladesh, and to entire nations such as the Maldives.
It is vital that we curb emissions as soon as possible to avoid an even greater rise, a German-led team of researchers said in a new report.
By 2300, the report projected that sea levels would gain by 0.7-1.2 metres, even if almost 200 nations fully meet goals under the 2015 Paris Agreement.
Targets set by the accords include cutting greenhouse gas emissions to net zero in the second half of this century.
Ocean levels will rise inexorably because heat-trapping industrial gases already emitted will linger in the atmosphere, melting more ice, it said.
In addition, water naturally expands as it warms above four degrees Celsius (39.2°F).
The report also found that every five years of delay beyond 2020 in peaking global emissions would mean an extra 20 centimetres (8 inches) of sea level rise by 2300.
‘Sea level is often communicated as a really slow process that you can’t do much about … but the next 30 years really matter,’ lead author Dr Matthias Mengel, of the Potsdam Institute for Climate Impact Research, in Potsdam, Germany, told Reuters.
None of the nearly 200 governments to sign the Paris Accords are on track to meet its pledges.
Although experts warn about the dangerous of increased sea ice, other studies this year have found that the amount in the ocean is dwindling.
In July, NASA had announced that the ice circling Antarctic had hit an all-time low – losing an area the size of Mexico
Floating ice off the southern continent steadily increased from 1979 and hit a record high in 2014.
Three years later, the annual average extent of Antarctic sea ice hit its lowest mark, wiping out three-and-a-half decades of gains, a NASA study of satellite data shows.
That means that, since 2014, Antarctica has lost the same amount of ice as has disappeared from the Arctic in more than three decades.