CAPE LEGOUPIL, Antarctica — From the ground in this extreme northern part of Antarctica, spectacularly white and blinding ice seems to extend forever. What can’t be seen is the battle raging thousands of feet below to re-shape Earth.
Water is eating away at the Antarctic ice, melting it where it hits the oceans. As the ice sheets slowly thaw, water pours into the sea — 130 billion tons of ice per year for the past decade, according to NASA satellite calculations. That’s the weight of more than 356,000 Empire State Buildings, enough ice melt to fill more than 1.3 million Olympic swimming pools. And the melting is accelerating.
In the worst-case scenario, Antarctica’s melt could push sea levels up 10 feet worldwide in a century or two, recurving heavily populated coastlines.
Parts of Antarctica are melting so rapidly it has become “ground zero of global climate change without a doubt,” said Harvard geophysicist Jerry Mitrovica.
Here on the Antarctic peninsula, where the continent is warming the fastest because the land sticks out in the warmer ocean, 49 billion tons of ice are lost each year, according to NASA. The water warms from below, causing the ice to retreat on to land, and then the warmer air takes over. Temperatures rose 5.4 degrees in the last half-century, much faster than Earth’s average, said Ricardo Jana, a glaciologist for the Chilean Antarctic Institute.
Robert Island hits all the senses: the stomach-turning smell of penguin poop; soft moss that invites the rare visitor to lie down, as if on a water bed; brown mud, akin to stepping in gooey chocolate. Patches of the moss, which alternates from fluorescent green to rust red, have grown large enough to be football fields. Though 97 percent of the Antarctic Peninsula is still covered with ice, entire valleys are now free of it.
Plant biologist Angelica Casanova began coming to the island in 1995. Increasingly, she observes, plants are taking root in the earth and stone deposited by retreating glaciers, she says.
“It’s interesting because the vegetation in some way responds positively. It grows more,” she said, a few steps from a sleeping Weddell seal. “What is regrettable is that all the scientific information that we’re seeing says there’s been a lot of glacier retreat and that worries us.”
Last month, scientists noticed in satellite images that a giant crack in an ice shelf on the peninsula called Larsen C had grown by about 12 miles in 2014. Ominously, the split broke through a type of ice band that usually stops such cracks. If it keeps going, it could cause the breaking off of a giant iceberg somewhere between the size of Rhode Island and Delaware, about 1,700 to 2,500 square miles, said British Antarctic Survey scientist Paul Holland. And there’s a small chance it could cause the entire Scotland-sized Larsen C ice shelf to collapse like its sister shelf, Larsen B, did dramatically in 2002.
A few years back, scientists figured Antarctica as a whole was in balance, neither gaining nor losing ice. Experts worried more about Greenland; it was easier to get to and more noticeable, but once they got a better look at the bottom of the world, the focus shifted. Now scientists in two different studies use the words “irreversible” and “unstoppable” to talk about the melting in West Antarctica. Ice is gaining in East Antarctica, where the air and water are cooler, but not nearly as fast as it is melting in the west.
Over at NASA, ice scientist Eric Rignot said the melting “is going way faster than anyone had thought. It’s kind of a red flag.”
What’s happening is simple physics. Warm water eats away at the ice from underneath. Then more ice is exposed to the water, and it too melts. Finally, the ice above the water collapses into the water and melts.
Climate change has shifted the wind pattern around the continent, pushing warmer water against and below the western ice sheet and the peninsula. The warm, more northerly water replaces the cooler water that had been there. It’s only a couple degrees Fahrenheit warmer than the water that used to be there, but that makes a huge difference in melting, scientists said.
The world’s fate hangs on how fast the ice melts. At its current rate, the sea level rise from Antarctica’s ice melt would be barely noticeable, about one-third of a millimeter a year.
But if all the West Antarctic ice sheet that’s connected to water melts unstoppably, as several experts predict, there will not be time to prepare. Scientists estimate it will take anywhere from 200 to 1,000 years to melt enough ice to raise seas by 10 feet, maybe only 100 years, in a worst-case scenario. If that plays out, developed coastal cities such as New York and Guangzhou could face up to $1 trillion a year in flood damage within a few decades; countless other settlements will be vulnerable.
“Changing the climate of the Earth or thinning glaciers is fine as long as you don’t do it too fast. And right now we are doing it as fast as we can,” said Rignot.
