![]() Warmer summers threaten Antarctica’s giant ice shelves because of the lakes they createįour giant ice shelves are still in good shapeĪntarctica’s four largest ice shelves are the Ross, Ronne, Filchner, and Amery. We’ve also seen entire ice shelves collapse when warmer air temperatures create surface meltwater that can cut through hundreds of metres of ice shelf. This year, Antarctica saw the lowest sea ice extent ever recorded since measurements began in the 1970s. We also know iceberg calving increases whenever Antarctica’s protective ring of sea ice weakens. We know one cause of ice shelf retreat is the thinning of ice shelves, which is largely caused by relatively warm seawater eroding the base of these shelves. But overall, these ice shelves are shrinking. Some ice shelves such as the Wilkins Ice Shelf have already seen catastrophic disintegration, while others are retreating slowly and some are even advancing. Why are Antarctic ice shelves shrinking? There’s no single answer. We found a majority of Antarctica’s ice shelves have lost mass since the late 1990s. So while no single calving event should be taken as cause for alarm, the long term trend is concerning. In any climate, we expect to see massive flat-top icebergs periodically break off and float away. We found the Pine Island Glacier and the so-called “Doomsday” Thwaites Glacier – which could destabilise the entire West Antarctic ice sheet if it melts – are highly sensitive to calving, and are already increasing their contribution to sea level rise as their protective ice shelves crumbled. ![]() Our work shows the drop in ice shelf area has led to more ice flowing into the sea since 2007, as calving has weakened ice shelves and allowed some of the world’s largest glaciers to accelerate. ![]() We built numerical models to figure out what ice shelf thinning and loss of area mean for the ability of ice shelves to resist new ice being pushed in from upstream glaciers. Sarah Thompson, Author provided What we measured Sørsdal Glacier in East Antarctica, where meltwater lakes have been appearing. But as climate change intensifies, Antarctica will begin melting in earnest, contributing more to sea level rise. To date, much of the concern about the cryosphere – the world’s frozen parts – has focused on the fast-melting Arctic sea ice. This has led Antarctica’s glaciers to begin adding more water to the oceans, and more quickly. Ice shelves are now weaker than at any time since at least the 1990s. We found Antarctica’s ice shelves have lost twice as much mass as previous studies suggested. We tracked how much extra ice had been lost as icebergs calve away from the retreating edge of the continent. ![]() Previous estimates of ice shelf loss come from satellite measurements, which captured ice shelves gradually thinning in recent years. Overall, the net loss of ice is about 6,000 billion tonnes since 1997. In research published today in Nature, we show these ice shelves have significantly reduced in area over the last 25 years due to more and more icebergs breaking off. ![]() Unfortunately, Antarctica’s ice shelves are not what they were. If they weren’t there, the glaciers would flow faster into the sea and melt, causing sea levels to rise. These shelves extend the glaciers into the ocean until they calve into icebergs.īut they also play a crucial role in maintaining the world as we know it, by acting as a brake on how fast the glaciers can flow into the ocean. As Antarctica’s slow rivers of ice hit the sea, they float, forming ice shelves. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |