In the fragment “Young and thin ice can regrow relatively quickly once the dark and cold winter sets in.”
The Arctic Ocean has lost 95 percent of its oldest ice
— a startling sign of what’s to come
By Chris Mooney
December 11, 2018
Over the past three decades of global warming, the oldest and thickest ice in the Arctic has declined by a stunning 95 percent, according the National Oceanic and Atmospheric Administration’s annual Arctic Report Card. The finding suggests that the sea at the top of the world has already morphed into a new and very different state, with major implications not only for creatures such as walruses and polar bears but, in the long term, perhaps for the pace of global warming itself.
The oldest ice can be thought of as a kind of glue that holds the Arctic together and, through its relative permanence, helps keep the Arctic cold even in long summers. “The younger the ice, the thinner the ice, the easier it is to go away,” said Don Perovich, a scientist at Dartmouth who coordinated the sea ice section of the yearly report.
If the Arctic begins to experience entirely ice-free summers, scientists say, the planet will warm even more, as the dark ocean water absorbs large amounts of solar heating that used to be deflected by the cover of ice. The new findings were published as climate negotiators in Poland are trying to reach a global consensus on how to address climate change.
In March, NASA scientists with the Operation IceBridge mission, which surveys the polar regions using research aircraft, witnessed a dramatic instance of the ongoing changes. Flying over the seas north of Greenland, in a region that usually features some of the oldest, thickest ice in the Arctic, they instead saw smooth, thin strips binding together the thicker, ridged pieces.
“I was just shocked by how different it was,” said NASA’s Nathan Kurtz, who has flown over the area multiple times. The floating sea ice had broken up entirely the previous month — very unusual for this location — and now was feebly freezing back together again.
Scientists think a strange wind event caused the breakup in this region just a few hundred miles south of the North Pole — so it’s unclear whether it is directly linked to climate change. Still, the breakup could be just one more sign of the growing fragility of the oldest ice.
The new findings about the decreasing age of ice in the Arctic point to a less noticed aspect of the dramatic changes occurring there. When it comes to the icy cap atop the Arctic Ocean, we tend to talk most often about its surface area — how much total ocean is covered by ice, rather than by open water. That’s easily visible — it can be glimpsed directly by satellite — and the area is, indeed, in clear decline.
But the loss of old and thick ice, and the simultaneous decline in the total ice volume, is even larger — and arguably a much bigger deal. Young and thin ice can regrow relatively quickly once the dark and cold winter sets in. But it may not add much stability or permanence to the Arctic sea ice system if it just melts out again the next summer.
The total volume of ice in September, the lowest ice month, declined by 78 percent between 1979 and 2012, the record low year. That’s according to an analysis by scientists at the University of Washington in Seattle called PIOMAS, or the Pan-Arctic Ice Ocean Modeling and Assimilation System — a top source for tracking ice volume.
In fairness, the ice volume has rebounded somewhat since 2012. And PIOMAS is only a model, cautioned the University of Washington’s Axel Schweiger, who runs the analysis. (The model draws upon direct measurements of ice thickness taken from submarines, satellites and other sources.) Still, Schweiger agreed that when you think about the total volume of the ice, rather than its mere surface extent, you realize that far more has been lost. “We’ve lost about half of the extent, we’ve lost half of the thickness, and if you multiply these two things, we’ve lost 75 percent of the September sea ice,” he said.
Going by PIOMAS’s numbers, the losses represent more than 10 trillion tons of ice. While the Arctic Ocean contained over 15 trillion tons of floating ice in 1979 during the month of September, in the same month in 2012, it averaged just under 3.5 trillion tons. This year, it averaged just 4.66 trillion tons in September.
“The Arctic is an indication of what’s coming to the rest of the globe,” said Walt Meier, a sea ice expert at the National Snow and Ice Data Center. “In the Arctic Ocean, a difference of 2 degrees can be huge. If it goes from 31 Fahrenheit to 33 Fahrenheit, you’re going from ice skating to swimming. … the Arctic is an early warning system for the climate.”
Available at: <https://www.washingtonpost.com/energy-environment/2018/12/11/arctic-is-even-worse-shape-than-you-realize/?noredirect=on&utm_term=.508085a17318>.
Retrieved on: July 2, 2019. Adapted.
PUC RJ 2020 - QUESTÃO 06
In the fragment “Young and thin ice can regrow relatively quickly once the dark and cold winter sets in.” (lines 55-57), sets in can be replaced, without change in meaning, by
(A) gets under way
(B) reaches its peak
(C) comes to an end
(D) is shorter than usual
(E) unexpectedly finishes
QUESTÃO ANTERIOR:
GABARITO:
(A) gets under way
RESOLUÇÃO:
Para acertar esta questão, o candidato deverá ser capaz de inferir o significado do phrasal verb “set in”, que significa “começar, ter início”. Portanto, o gabarito é a letra (A), “get under way” que significa “começar”. O fragmento em destaque no enunciado significa “O gelo jovem e fino pode regredir com relativa rapidez quando o inverno escuro e frio se inicia.” Tal gabarito encontra respaldo nos dicionários eletrônicos Longman e thefreedictionary, citados abaixo.
set in phrasal verb - if something sets in, especially something unpleasant, it begins and seems likely to continue for a long time Winter seems to be setting in early this year. Further economic decline set in during the 1930s. https://www.ldoceonline.com/dictionary/set-in
set in (of something unpleasant or unwelcome) begin and seem likely to continue.
"less hardy plants should be brought inside before cold weather sets in" get under way
To start. Let's get under way here you have an hour to complete the exam.I'm sure you can ask your question once the lecture gets under way.
https://idioms.thefreedictionary.com/getting+underway
As demais alternativas devem ser descartadas, visto que “set in” não significa
- “reach its peak” (“alcança o seu pico”), como na opção (B);
- “comes to an end” (“chega ao fim”), como na opção (C);
- “is shorter than usual” (“é mais breve do que o normal”), como na opção (D);
- “unexpectedly finishes” (“termina inesperadamente”), como na opção (E).
PRÓXIMA QUESTÃO:
QUESTÃO DISPONÍVEL EM:
