Page 28 - ARUBA TODAY

A28 SCIENCE
Thursday 14 June 2018

Melting of Antarctica is speeding up, worrying scientists

By SETH BORENSTEIN The study is the second of land glaciers elsewhere,
WASHINGTON (AP) — The assessments planned every Greenland's dwindling ice
melting of Antarctica is several years by a team sheet and the fact that
accelerating at an alarming of scientists working with warmer water expands.
rate, with about 3 trillion NASA and the European "Under natural conditions
tons of ice disappearing Space Agency. Their we don't expect the ice
since 1992, an international mission is to produce the sheet to lose ice at all,"
team of ice experts said in most comprehensive look Shepherd said. "There are
a new study. at what's happening to no other plausible signals
In the last quarter century, the world's vulnerable ice to be driving this other than
the southern-most sheets in Antarctica and climate change."
continent's ice sheet — a Greenland. Shepherd cautioned that
key indicator of climate Outside experts praised the this is not a formal study
change — melted into work as authoritative. that determines human
enough water to cover Unlike single-measurement fingerprints on climate
Texas to a depth of nearly studies, this team looks at events.
13 feet (4 meters), scientists ice loss in 24 different ways Forces "that are driving
calculated. All that water This January 2018 photo provided by researcher Andrew using 10 to 15 satellites, these changes are not
made global oceans rise Shepherd shows an unusual iceberg near the Rothera Research as well as ground and going to get any better in
about three-tenths of an Station on the Antarctic Peninsula. air measurements and a warming climate," said
inch (7.6 millimeters). Associated Press computer simulations, University of Colorado ice
From 1992 to 2011, said lead author Andrew scientist Waleed Abdalati,
Antarctica lost nearly 84 the journal Nature . They are happening faster Shepherd of the University a former NASA chief
billion tons of ice a year (76 "I think we should be than we expected." of Leeds in England. scientist who wasn't part of
billion metric tons). From worried. That doesn't mean Part of West Antarctica, It's possible that Antarctica the study team.
2012 to 2017, the melt rate we should be desperate," where most of the melting alone can add about half In Antarctica, it's mostly
increased to more than 241 said University of California occurred, "is in a state of a foot (16 centimeters) to warmer water causing the
billion tons a year (219 billion Irvine's Isabella Velicogna, collapse," said co-author sea level rise by the end of melt. The water nibbles at
metric tons), according to one of 88 co-authors. Ian Joughin of the University the century, Shepherd said. the floating edges of ice
the study Wednesday in "Things are happening. of Washington. Seas also rise from melting sheets from below. q

NASA rover knocked out as gigantic dust storm envelops Mars

By MARCIA DUNN be like once it clears."
Associated Press All flight controllers can do
CAPE CANAVERAL, Fla. (AP) is wait for the storm to pass
— A NASA rover on Mars and the sky to clear, of-
has been knocked out by ficials said, and hope Op-
gigantic dust storm that en- portunity calls home.
velops the planet and blots Flight controllers tried late
out the sun. Tuesday night to contact
Officials said Wednesday Opportunity, but the rover
they're hopeful the Oppor- did not respond. The storm
tunity rover will survive the has been growing since the
storm, which already cov- end of May with unprece-
ers one-quarter of Mars and dented speed.
is expected to encircle the Opportunity's batteries are
red planet in another few likely so low that only a
days. It could be weeks or clock is still working, to wake
even months, though, until the spacecraft for periodic
the sky clears enough for This composite image made from observations by NASA's Mars Reconnaissance Orbiter spacecraft power-level checks, ac-
sunlight to reach the Mar- shows a global map of Mars with a growing dust storm as of June 6, 2018. cording to officials.
tian surface and recharge Associated Press NASA launched the twin
Opportunity's batteries rovers Opportunity and
through its solar panels. complete round-the-clock Callas, the Opportunity storm is threatening, and Spirit in 2003 to study Mar-
For now, Mars' oldest work- darkness. project manager at NASA's we don't know how long it tian rocks and soil. Spirit
ing rover is stuck in the mid- "By no means are we out of Jet Propulsion Laboratory in will last, and we don't know hasn't worked for several
dle of the raging storm, in the woods here," said John Pasadena, California. "This what the environment will years. Opportunity, howev-
er, has kept exploring well
past its expected mission
lifetime.
"Keep in mind, we're talking
about a rover that's been
working at Mars, hanging
in there, for 15 years and
designed just for 90 days. It
just doesn't get any better
than that," said Jim Watzin,
director of NASA's Mars ex-
ploration program.q