Why are ice shelves important

If you've ever tried to move a completed puzzle or hexagonal board game across a table, you've quickly discovered how problematic it can be when pieces move at different rates. When atmospheric and oceanic factors cause the ice to thin, flow lines where the glaciers feed into the shelf can rupture.

In addition, as more and more ice is lost at the front of the shelf via calving, the lack of support feeds back through the shelf and results in an increase in crevasses and rifts, which are "tears" in the ice caused by internal stresses as the ice moves.

Areas of weakness and strain are naturally occurring but, in combination with atmospheric and oceanic warming, can result in the collapse of an ice shelf. Melting ice shelves don't contribute to sea level rise, right? Wll, ice shelves don't contribute directly to sea level rise because they're already in the water when they break off, there's no additional displacement.

However, they do contribute indirectly in several ways. An ice shelf acts as a support for the ice sheet behind it remember, the ice sheet is the part that's on land. The collapse of the support weakens the entire sheet structurally and allows the glaciers feeding into it to flow faster, thereby accelerating the entire sheet toward the ocean. Recent research has suggested that feeder glaciers can flow up to five times faster after a rapid collapse.

As more of an ice sheet ends up in the ocean, the sea level rises much faster. As we discussed in a previous post on climate change , the oceans have already risen 19 cm in the last century, at a rate of about 1—3 mm per year , and the melting we've already set in motion is predicted to raise them another meter by the end of the century— at minimum —even if we stop all emissions today.

It's difficult to predict how much sea-level rise we'll face—and when—because ice sheets and shelves respond to climate change in nonlinear ways, meaning that the response of ice sheets to a changing climate is not directly proportional to the size of the change. Recent studies that factor in the increased melting from the Greenland and Antarctic ice sheets have predicted dire results: if greenhouse gas emissions continue or increase, oceans could rise by nearly 2 meters by That's double the previous estimates, for anyone keeping track at home.

Not every country will experience the same level of sea-level rise , however. If the ice shelves were in a stable, steady state, then they might oscillate back and forth between gaining mass and losing mass, Adusumilli noted.

But for the last 25 years, "there's always mass loss," he said. It never goes from mass gain to mass loss. Rising sea levels are the biggest concern about ice loss from Antarctic glaciers. But melting ice shelves are worth keeping an eye on for another reason, Adusumilli added. The cold, fresh water can form a rigid layer on the surface of the ocean.

Some researchers believe that this, in turn, could allow deeper, warmer layers of the ocean to grow even warmer. And when these warm layers well up at the edge of the continent, they could cause the ice shelves to melt even faster.

Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Calving is a type of ablation. Ice shelves grow when they gain ice from land, usually from glaciers or ice streams. Rising global temperatures have already had a noticeable impact on the health of ice shelves and the glaciers that feed them. Ice shelves do not contribute directly to sea level rise because they already float on the ocean surface.

However, warmer temperatures take their toll on the waters surrounding shelves, leading to less protection from high winds and warm water. There have been several instances in recent decades of some of the most prominent shelves on earth breaking up, such as the Larsen B ice shelf off the eastern coast of Antarctica in Once a shelf breaks up or breaks off of the coast, the dynamics that controlled the source like a glacier are disrupted.

Type and press enter to search. The crucial role of ice shelves. Tracking the age of the core. What is an ice shelf? Why are ice shelves important? Simplified cartoon of a tributary glacier feeding into an ice shelf, showing the grounding line where the glacier begins to float and how an ice shelf can be thinning from the surface and from below Ice shelves are essential in the stability of the ice sheet because they act as buttresses.

You can see it here: What happened? When ice shelf retreats to the grounding line, the buoyant force that used to offset glacier flow are not efficient to slow down the glacier on its way to the sea.