Antarctica is losing ice at an increasingly rapid rate

Antarctica is losing ice at an increasingly rapid rate

Antarctica is losing ice at an increasingly rapid rate

Between 1992 and 2017, the Antarctic ice sheet shed roughly 3 trillion metric tons of ice-causing the global average sea level to rise almost a third of an inch (7.6 millimeters).

The most complete analysis to date measuring ice sheet changes in Antarctica reveals Earth's southernmost continent has lost some 3 trillion tonnes of ice over the past quarter-century.

Shepherd says they've seen the most dramatic effects in West Antarctica, where the ice sheet rests on the sea bed. "Since around 2010, 2012, we can see that there's been a sharp increase in the rate of ice loss from Antarctica". After 2012, however, the losses have skyrocketed to almost triple that amount - 219 billion tonnes of ice lost per year, up until 2017.

Overall between 1992 and 2017, Antarctica's ice sheet lost 3 trillion tons of ice - enough water to cover Texas to a depth of almost 13 feet, scientists calculated. That's an 146-billion-metric-ton leap.

Unlike single-measurement studies, this team looks at ice loss in 24 different ways using 10 to 15 satellites, as well as ground and air measurements and computer simulations, said lead author Andrew Shepherd of the University of Leeds in England.

"We appear to be on a pathway to substantial ice-sheet loss in the decades ahead, with longer-term consequences for enhanced sea level rise". The Antarctic Peninsula - the portion of the continent that reaches out for the southern tip of South America - has seen an increase from an average of 7 billion tonnes per year, up to 33 billion tonnes per year in that same time period. And as oceans warm, their waters expand and occupy more space, also raising sea levels.

Looking closer, the rapid, recent changes are nearly entirely driven by the West Antarctic ice sheet, which scientists have long viewed as an Achilles' heel.

One of those studies, co-authored by physical oceanographer and climate scientist Steve Rintoul at Australia's CSIRO contemplates a grim choose-your-own-adventure style environmental dilemma - contrasting what Antarctica is projected to look like in the year 2070 if today's high greenhouse emissions remain unchanged, versus the preferable trajectory if climate action reins in carbon pollution.

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During southern summer, sunlight warms dust particles, lifting them higher into the atmosphere and creating more wind. The problem isn't the dust, but the darkness it creates. "They can crop up suddenly but last weeks, even months".

A new climate assessment called the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) found a startling rise in sea level.

They also said governments should take note.

Granted, there's no proof the current rate of change in Antarctica will continue.

"I don't know if it's going to keep exactly tripling, but I think it has a lot of potential to keep significantly increasing, " said Velicogna.

East Antarctica, which makes up two-thirds of the continent, is a remote region of an already remote location, where data is scarcer because there are fewer measurement stations, Koppes said. "We will not necessarily see exclusively rapid retreat, " said Christianson, noting that as glaciers like Pine Island retreat backwards down a submarine, downhill slope, they will sometimes encounter bumps that slow down their movement. "But remember for the northern hemisphere, for North America, the fact that the location in West Antarctica is where the action is amplifies that rate of sea level rise by up to an about additional 25 percent in a city like Boston or NY".

Shepherd said the ice on West Antarctica can be melted by very small changes in ocean temperature.

Rising sea levels can have a unsafe impact on coastal habitats and communities as flooding increases along with higher tides and stronger storm surges.

"The kinds of changes that we see today, if they were not to increase much more. then maybe we're talking about something that is manageable for coastal stakeholders, " said DeConto. "Put simply if we can not collectively tackle climate change, then it's unlikely we will maintain Antarctica as a place for peace, nature and science".

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