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Huge ancient ice wall across the Bering Strait may have triggered Ice Age

Huge ancient ice wall across t...
A new study suggests the last ice age was caused by an ice wall across the Bering Strait
A new study suggests the last ice age was caused by an ice wall across the Bering Strait
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A new study suggests the last ice age was caused by an ice wall across the Bering Strait
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A new study suggests the last ice age was caused by an ice wall across the Bering Strait

While climate change is the hot topic (pun intended) of the day, the truth is Earth has always gone through semi-regular cycles of warmer and colder periods. But while many of these events can be linked to specific causes, like changes in the planet's orbit (or say, human activity) the cause of the last major shift, which occurred about a million years ago, has remained a mystery. By taking samples from the ocean floor of the Bering Sea, a new study may have uncovered the mechanism behind this outlier event.

The Pleistocene period is often known casually as "The" Ice Age, and with good reason. The Earth was a much colder place than it is today, and a long-term pattern of more intense cold conditions kicked off with the Mid-Pleistocene Transition (MPT) about a million years ago.

But what exactly caused that transition has long been the subject of debate. Most of these events are triggered by what are known as Milankovitch Cycles, which include changes in the Earth's orbital path around the Sun, the tilt of its axis and the wobble of its spin. These affect how much sunlight hits the Northern Hemisphere, which can cause glaciers to either build up or melt away. Factors like CO2 levels in the atmosphere play a role, too, amplifying the effects.

The problem is that the MPT falls outside of these normal cycles, so scientists have been unsure exactly what caused this long-term global climate shift. One theory suggests that around that time, the oceans may have become more stratified, meaning the water forms distinct layers that don't mix too easily, thanks to differences in temperature and salinity. As a result, the oceans can absorb more CO2 from the atmosphere than usual and cause global temperatures to plummet.

To test the idea, the team took deep sediment cores from the bottom of the Bering Sea. By studying the chemistry of the sediment and fossil shells from marine microorganisms, the team can see a detailed history of changes in the area, including the masses of water at the surface and bottom of the ocean.

The researchers found that the Bering Sea did become more stratified around the time of the MPT. That means that CO2 locked away deep in the subarctic North Pacific Ocean stayed down there, so the sea absorbs even more of the gas, which in turn leads to global cooling. The cause of this, the team says, was that the Bering Strait – the short stretch of ocean between eastern Siberia and Alaska – iced over during a glaciation.

"Today much of the cold water produced by sea ice action flows northward into the Arctic Ocean through the Bering Strait," says Sev Kender, lead author of the study. "As glaciers grew and sea levels fell around 1 million years ago, the Bering Strait would have closed, retaining colder water within the Bering Sea. This expanded watermass appears to have stifled the upwelling of deep CO2-rich water and allowed the ocean to sequester more CO2 out of the atmosphere. The associated cooling effect would have changed the sensitivity of Earth to orbital cycles, causing colder and longer glaciations that characterize climate ever since.

"Our findings highlight the importance of understanding present and future changes to the high latitude oceans, as these regions are so important for long term sequestration or release of atmospheric CO2."

The research was published in the journal Nature Communications.

Source: University of Exeter

13 comments
dBro
Instead of trying to remove CO2 it looks like simply blocking the Strait would cool the Arctic water enough to offset global climate change. This could be accomplished with man made reefs or simply parking unused tankers along the path. Ice would only have blocked the strait to a depth of 20 to 50 feet in the beginning so it is not by any means impossible to accomplish the same thing. Even a fence would do it.
Chris Coles
It would seem that no one on the research team has read; Earth's Shifting Crust by Charles Hapgood; or, for that matter, ever lived here in East Hampshire in the UK, with a sea floor surface to walk upon, covered by fossilised sea urchins.
Rumata
Since large hot sea water surfaces can emit much more CO2 than small cold seasurfaces, it is very unlikely, that the small Bering Sea could determinate the CO2-level of the atmophere. Also, since there is still no scientific evidence that atmospheric CO2 could have a measureable effect on the global average temperature, so it is very unlikely, that any decrease in atmospheric CO2-level could cause such a drastic cooling like an Ice Age. The global average temperature is determined basically by global wind systems and cloud formation, because these are the main factors determining the radiation absorptivity, reflexivity and emissivity of the Earth. Hence, the real answer for climate change could be in the changes in global wind systems. A totally unknown topic, CO2-believers don't even mention.
Travis Tarr
The rise and fall of great Empires, Dynasties and other civilisations had no modern day Co2 production, but they failed. So what happened? The SUN is cyclical. Cosmic rays anyone? Whoa... We must think bigger than the man made co2 tax scam or ice walls. Change will happen and Food is the problem. Grand Solar Minimum Much?
edjudy
Rumata seems to forget that warming/cooling has an effect on wind patterns and ocean currents. Which leads to cause-and-effect discussions . . . and discussions about, "does this amplify that - or does this damp that?"
Iman Azol
Rumata: Don't bring facts into this. The Church of AGW will scourge you. My takeaway using their logic, however, is we need enough CO2 to be damned sure this doesn't happen again, because ice ages are bad for civilization.
Douglas Bennett Rogers
This looks like hedge research to me. There is a perceived need to elevate the importance of CO2.
Don Duncan
Less CO2 is less fuel for plants who breathe it. Animals need plants to live. We are animals. It follows we need to worry about an ice age, not warming. Bring on the CO2! (If it really does increase temp.) I doubt it. There is a strong correlation between sunspots and weather. It may be impossible to stop the big swings. One answer is to build orbiting cities, another is to inhabit other bodies, another is to learn how to live in space. Adapt or become extinct.
Kpar
For much more on this subject, I recommend the curious go to Youtube and look up a fellow named Randall Carlson. He has much to say on this (and other) subjects, based on known, but under-discussed events of the past.
ljaques
If dBro's comments are any indication, then clazy climate zealots will attempt to bring on another ice age starting RIGHT NOW. God help us. C'mon, guys. Settle down. Mother Nature has this in hand without our butting in with our lamebrain notions. Let HER handle this, eh?