Could an increase in Antarctic ice levels trigger a new ice age and help reverse global warming?


Scientists studying the causes of ice ages say that an increase in Antarctic ice levels could be enough to trigger a new ice age that would reverse the current warming of our planet.

As climate change continues to cause rising global temperatures that are busy melting the ice caps, scientists are racing to figure out what caused the ice age. Such information could give us a way to reverse climate change and restore the ice caps to normal.

Sea level rise is a growing problem that already threatens to swallow islands under the sea. As more ice melts in the Arctic and Antarctic, sea levels will only keep rising, especially when you add glacier melt to the equation.

Mt. Herschel in Antarctica. Image via Wikimedia.

The question many are asking is how can we reverse this damage? Is there a way to stop global temperature rise and prevent the ice caps from totally disappearing?

It may be too late to save many low lying coastal areas and some islands, but there may still be time to save the rest.

Multiple strategies have been offered, such as planting billions of trees to suck up the carbon emissions that are causing the greenhouse gas effect, which traps carbon dioxide and other gases in the atmosphere, resulting in hotter temperatures. We could also eliminate carbon emissions so that no new emissions are added. Combining these two strategies offers the best solution.

But another strategy could be to cause a new ice age.

Causing an ice age?

Millions of years ago, a shift in our planet’s natural cycle touched off a series of ice ages, the remnants of which can still be seen today via glaciers and in ice cores. But once the Industrial Revolution began in the 19th century, global temperatures have continued to rise as more and more carbon emissions are produced.

Now the world faces a crisis humanity has never faced before. So, is it possible to cause another ice age to reverse the warming trend?

“One key question in the field is still what caused the Earth to periodically cycle in and out of ice ages,” University of Chicago Assistant Professor Malte Jansen said in a press release. “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.”

Jansen and postdoctoral researcher Alice Marzocchi studied this carbon balance and hypothesize that the ice caps act as a lid on the ocean surface preventing a lot of carbon from escaping to the atmosphere. This fragile cycle of melting and freezing has been occurring for 2.5 million years, keeping greenhouse gases under the surface of the ocean at bay for many millennia, but that’s all about to change as the ice melts uncontrollably.

 

The ice sheet in Greenland as seen from space. In the near future, it will be completely melted, changing the landscape and our climate to the extreme. Image via Wikimedia.

The duo used computer simulations to bolster their theory, however, how this natural system works isn’t totally clear.

“The most plausible explanation is that there was some change in how carbon was divided between the atmosphere and the ocean,” Jansen said. “There’s no shortage of ideas about how this happens, but it’s not quite clear how they all fit together.”

First, the atmosphere has to cool just enough for ice to begin building up on the surface, contributing to the natural ocean circulation as we understand it today.

“The Southern Ocean around Antarctica plays a key role in ocean circulation, as it is a region where deep waters rise to the surface before disappearing again into the abyss,” Jansen said. “As a result, increased Antarctic sea ice has outsize consequences.”

According to their study published by Nature:

Palaeo-oceanographic reconstructions indicate that the distribution of global ocean water masses has undergone major glacial–interglacial rearrangements over the past ~2.5 million years. Given that the ocean is the largest carbon reservoir, such circulation changes were probably key in driving the variations in atmospheric CO2 concentrations observed in the ice-core record.

However, we still lack a mechanistic understanding of the ocean’s role in regulating CO2 on these timescales. Here, we show that glacial ocean–sea ice numerical simulations with a single-basin general circulation model, forced solely by atmospheric cooling, can predict ocean circulation patterns associated with increased atmospheric carbon sequestration in the deep ocean. Under such conditions, Antarctic bottom water becomes more isolated from the sea surface as a result of two connected factors: reduced air–sea gas exchange under sea ice around Antarctica and weaker mixing with North Atlantic Deep Water due to a shallower interface between southern- and northern-sourced water masses.

These physical changes alone are sufficient to explain ~40 ppm atmospheric CO2 drawdown—about half of the glacial–interglacial variation. Our results highlight that atmospheric cooling could have directly caused the reorganization of deep ocean water masses and, thus, glacial CO2 drawdown. This provides an important step towards a consistent picture of glacial climates.

A view of Antarctica and the ice sheet surrounding it. It’s melting slower than the Arctic ice sheet, but will eventually succumb to rising global temperatures as well. Image via Wikimedia.

“What this suggests is that it’s a feedback loop,” National Oceanography Center researcher Marzocchi said. “As the temperature drops, less carbon is released into the atmosphere, which triggers more cooling.”

In fact, the ice sheets are an incredibly important factor in keeping carbon stored deep under the ocean.

“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. “The ocean is the largest carbon reservoir over geological timescales. So studying the role that the ocean plays in the carbon cycle helps us more accurately simulate future environmental change.”

A glacier in Alaska that is also at risk of melting out of existence. Image via Wikimedia.

Indeed, it could also provide a way to stop climate change in its tracks and perhaps even reverse it. Again, it all comes back to reducing carbon emission production and getting rid of the carbon emissions that are already in the atmosphere. Doing that would allow for a cooling that would result in an ice buildup that could trigger a minor ice age, thus setting the clock back on global warming. Causing an ice age may not seem like a good idea, but we need cooler temperatures right now before global temperatures cross a red line that will result in worse droughts and severe water insecurity. Because frozen water is better than no water at all…


Featured Image: Wikimedia


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