R Kym Horsell
2016-05-06 07:46:41 UTC
Forest fires, coral bleaching -- what's sommin else that will never happen?
...
Oh, here's one.
<http://e360.yale.edu/feature/
abrupt_sea_level_rise_realistic_greenland_antarctica/2990>
Abrupt Sea Level Rise Looms As Increasingly Realistic Threat [in color]
nicola jones
05 May 2016
[Image] Ninety-nine percent of the planet's freshwater ice is locked
up in the Antarctic and Greenland ice caps. Now, a growing number of
studies are raising the possibility that as those ice sheets melt, sea
levels could rise by six feet this century, and far higher in the
next, flooding many of the world's populated coastal areas.
West Antarctica's glaciers and floating ice shelves are becoming
increasingly unstable.
Last month in Greenland, more than a tenth of the ice sheet's surface
was melting in the unseasonably warm spring sun, smashing 2010's
record for a thaw so early in the year. In the Antarctic, warm water
licking at the base of the continent's western ice sheet is, in
effect, dissolving the cork that holds back the flow of glaciers into
the sea; ice is now seeping like wine from a toppled bottle.
The planet's polar ice is melting fast, and recent satellite data,
models, and fieldwork have left scientists sobered by the speed of the
sea level rise we should expect over the coming decades. Although
researchers have long projected that the planet's biggest ice sheets
and glaciers will wilt in the face of rising temperatures, estimates
of the rate of that change keep going up. When the Intergovernmental
Panel on Climate Change (IPCC) put out its last report in 2013, the
consensus was for under a meter (3.3 feet) of sea level rise by
2100. In just the last few years, at least one modeling study suggests
we might need to double that.
Eric Rignot at the University of California, Irvine says that study
underscores the possible speed of ice sheet melt and collapse. "Once
these processes start to kick in," he says, "they're very fast."
The Earth has seen sudden climate change and rapid sea level rise
before. At the end of the planet's last glaciation, starting about
14,000 years ago, sea levels rose by more than 13 feet a century as
the huge North American ice sheet melted.
Greenland is losing some 200 billion tons of ice each year. That rate
doubled from the 1900s to the 2000s.
But researchers are hesitant about predicting similarly rapid climate
shifts in our future given the huge stakes involved: The rapid
collapse of today's polar ice sheets would erase densely populated
parts of our coastlines.
"Today, we're struggling with 3 millimeters [0.1 inch] per year [of
sea level rise]," says Robert DeConto at the University of
Massachusetts-Amherst, co-author of one of the more sobering new
studies. "We're talking about centimeters per year. That's really
tough. At that point your engineering can't keep up; you're down to
demolition and rebuilding."
Antarctica and Greenland hold the overwhelming majority of the world's
ice: Ninety percent of the planet's freshwater ice is locked up in
Antarctica's ice cap and nine percent in Greenland's. Today, the ice
sheet that's inarguably melting fastest is Greenland. That giant block
of ice, which has the potential to raise global sea levels by 23 feet
if it melts in its entirety, is losing some 200 billion tons of ice
each year. That rate has doubled from the 1900s to the 2000s.
"We are seeing changes in Greenland in all four corners, even in the
far north," says Rignot. Many of the outlet glaciers that flow down
fjords into the sea, which were "on the fence" about retreating or
advancing over the past decade, are now "starting to fall apart," he
says.
Danish Meteorological Institute
<Loading Image...
>
Illustration of the rapid expansion of ice melt on Greenland over just
two days in April 2016.
And they're moving fast. "The flow speeds we talk about today would
have been jaw-dropping in the 1990s," says Ted Scambos of the
University of Colorado's National Snow and Ice Data
Center. Greenland's Jakobshavn Glacier dumped ice into the sea at the
astonishing rate of 150 feet per day in the summer of 2012. The most
dramatic action in Greenland is simply from surface melting, as
temperatures there and across the Arctic have soared in the last four
decades. In 2012, Greenland lost a record 562 billion tons of ice as
more than 90 percent of its surface melted in the summer sun.
Many questions remain about the physics of Greenland's ice loss, such
as whether meltwater gets soaked up by a `sponge' of snow and ice, or
trickles down to lubricate the base of the ice sheet and speed its
seaward movement. Most modeling work has been about how Greenland's
melt tracks rising air temperatures; far less is known about how
warming waters might eat away at the edges of its ice sheet. Rignot is
part of a team now launching the Oceans Melting Greenland project
(with the intentionally punny acronym OMG) to investigate that. These
uncertainties make Rignot think that estimates of Greenland's melt -
contributing as much as 9 inches of global sea level rise by 2100,
according to the 2013 IPCC report - have been far too
conservative. Assuming that the Greenland ice sheet's demise "will be
slow is wishful thinking," Rignot says.
But most scientists say there shouldn't be too many serious surprises
about the physics governing Greenland's ice loss. Although the ice
sheet can be expected to steadily melt in the face of rising
temperatures, Greenland's ice cap shouldn't rapidly collapse, because
most of its ice sits safely on rock far above sea level. "Greenland is
more predictable and straightforward," says DeConto.
For fear of rapid, runaway collapse, the research community turns its
eyes south.
Antarctica is, for now, losing ice more slowly than Greenland. The
latest data from the GRACE project - twin satellites that measure mass
using gravity data - say Antarctica is losing about 92 billion tons of
ice per year, with that rate having doubled from 2003 to 2014.
The sizeable western half of Antarctica holds some of the
fastest-warming areas on the planet.
But Antarctica is vast - 1.5 times the size of the United States, with
ice three miles thick in places - and holds enough ice to raise global
sea levels by roughly 200 feet.
The larger, eastern half lies mostly above sea level and remains very
cold; researchers have typically considered its ice stable, though
even that view is beginning to change. The sizeable western half of
the Antarctic, by contrast, has its base lying below sea level, and
holds some of the fastest warming areas on the planet. "You look at
West Antarctica and you think: How come it's still there?" says
Rignot.
Warming ocean water licking at the underside of the floating edges of
the Western Antarctic Ice Sheet is eating away at the line where the
ice rests on solid rock. Much of the bedrock of the Antarctic slopes
downward toward the center of the continent, so as the invading water
flows downhill it seeps further and further inland, causing
ever-larger chunks of glaciers to flow faster into the sea. This
so-called "grounding line" has been eroding inland rapidly, in some
parts of West Antarctica at rates of miles per year. In 2014,
satellite radar images revealed just how vulnerable five massive
glaciers flowing into the Admundsen Sea are from this effect. And a
2015 paper showed that the same thing is happening more slowly to
Totten Glacier, one of the biggest glaciers in the east.
Such dramatic processes have been the bane of Antarctic modeling and
the reason why scientists have been loathe to put a number on sea
level contributions from a melting southern continent. Then in March
came a report in Nature that some say represents a step change in our
ability to do that. DeConto and David Pollard of Pennsylvania State
University put into their ice sheet model two basic phenomena:
meltwater trickling down to lubricate glacier flow, and giant walls of
ice (created when the ends of glaciers snap off) simply collapsing
under their own weight. These new modeling parameters gave DeConto and
Pollard a better understanding of past sea level rise events. For the
Pliocene era 3 million years ago, for example - when seas were dozens
of feet higher than today - older models estimated that a partially
melting Antarctic added about 23 feet to global sea level rise. The
new model increased Antarctica's contribution to sea level rise during
the Pliocene to 56 feet.
<Loading Image...
>
Satellite image showing sediment plumes from meltwater exiting
glaciers in Greenland.
Turning their model to the future, DeConto and Pollard project more than
three feet of sea level rise from Antarctica alone by 2100 - assuming
growing greenhouse gas emissions that boost the planet's temperature by
about 4 degrees C (7 degrees F). That is far more than the last IPCC
estimate in 2013, which projected less than eight inches of sea level rise
from a melting Antarctic by 2100, with a possibility for inches more from
the dramatic collapse of Antarctic glaciers.
Even DeConto admits that, under the model used in his paper, the timing and
pace of Antarctica's ice loss is "really uncertain" - it could be a decade
or two, or three or four, before these dramatic processes start to kick in,
he says. "The paper just shows the potentials, which are really big and
really scary," says DeConto. But Scambos and other observers call DeConto's
numbers "perfectly plausible."
Researchers could better pin down their models if they could track the rate
of sea level rise from polar ice sheet collapse in the past, but this has
proven hard to do. When seas rose a whopping 13 feet per century at the end
of the last glaciation (the current record-holder for known rates of sea
level rise in the past), much of the water came from an ice sheet over North
America, where there isn't one today. "I wouldn't use that as an analogue
for the future," says paleo-geologist Andrea Dutton of the University of
Florida, who wrote a recent review of past records of sea level rise. "But
it has important lessons for us nonetheless - that ice sheets can retreat
suddenly and in steps instead of gradually."
For a better analogue of what's going on today, researchers often look to
the last interglacial period, about 120,000 years ago, when temperatures
were about a degree warmer than pre-industrial levels and seas were 20 to 30
feet higher than today. Ice cores from Greenland have suggested that much of
that water must have come from the Antarctic. To find out just how fast sea
levels rose at that time, Dutton is now looking at old corals in Mexico,
Florida, and Australia; corals can be used to track sea level, since they
grow in shallow waters to capture sunlight.
--
Tesla Just Made Its Huge Model 3 Challenge Even Huger
WIRED, 05 May 2016 18:30Z
Elon Musk moved his desk. He now sits at the end of the production line at
Tesla Motors' factory in Fremont, California, and he's stashed a sleeping
bag in a nearby conference room.
Opinion:Tesla investors better be ready for wild ride -- CNBC
In Depth:Elon Musk Keeps Promising the Impossible. I Think I Know Why.
-- Slate Magazine
Winnipeg weather record set with 33-degree scorcher
CBC.ca, 05 May 2016 19:25Z
Winnipeg set a hot weather record on Thursday, when the mercury climbed to
33.2 C before 2 p.m.. The previous warm weather record for May 5 was set in
1926, when it was 31.7 C. The heat wave won't last long, though;
temperatures are expected to fall ...
Winnipeg hits 33 C, previous warm-weather record for May 5 was 31.7 C
CBC.ca, 05 May 2016 20:21Z
Manitoba broke 22 hot weather records Thursday, with the mercury climbing to
34.9 C in Winnipeg alone, making it the warmest place in Canada.
Alberta Declares State Of Emergency As Thousands Flee Massive Wildfire
ClimateProgress, 06 May 2016 8:18am
The Canadian province of Alberta declared a state of emergency Wednesday as
88,000 people in the city of Fort McMurray were forced to flee a fast-moving,
immense wildfire. The blaze has already destroyed 1,600 buildings, including
a school...
cold, rainy weather welcome after Tasmania's driest April on record
ABC Online, 05 May 2016 22:22Z
This week's rain has come with dam levels at 13 per cent after the driest
April on record. Hydro Tasmania has been drawing heavily on its storages
while the disabled Basslink electricity interconnector was not able to
import power.
'Armored Closet' Offers Tornado Safety Inside Your Home
CBS Local, 06 May 2016 03:23Z
Fort Worth (CBSDFW.COM). Depending on the home, it can be a challenge to
find a "safe-spot" during a tornado warning in North Texas.
More corals die in northern Great Barrier Reef
[Image] Coral bleached white in shallow waters off Lizard Island in the
Great Barrier Reef
ABC News, 06 May 2016 07:02Z
More coral has bleached and died in the northern section of the Great
Barrier Reef in the past month, new surveys reveal.
...
Oh, here's one.
<http://e360.yale.edu/feature/
abrupt_sea_level_rise_realistic_greenland_antarctica/2990>
Abrupt Sea Level Rise Looms As Increasingly Realistic Threat [in color]
nicola jones
05 May 2016
[Image] Ninety-nine percent of the planet's freshwater ice is locked
up in the Antarctic and Greenland ice caps. Now, a growing number of
studies are raising the possibility that as those ice sheets melt, sea
levels could rise by six feet this century, and far higher in the
next, flooding many of the world's populated coastal areas.
West Antarctica's glaciers and floating ice shelves are becoming
increasingly unstable.
Last month in Greenland, more than a tenth of the ice sheet's surface
was melting in the unseasonably warm spring sun, smashing 2010's
record for a thaw so early in the year. In the Antarctic, warm water
licking at the base of the continent's western ice sheet is, in
effect, dissolving the cork that holds back the flow of glaciers into
the sea; ice is now seeping like wine from a toppled bottle.
The planet's polar ice is melting fast, and recent satellite data,
models, and fieldwork have left scientists sobered by the speed of the
sea level rise we should expect over the coming decades. Although
researchers have long projected that the planet's biggest ice sheets
and glaciers will wilt in the face of rising temperatures, estimates
of the rate of that change keep going up. When the Intergovernmental
Panel on Climate Change (IPCC) put out its last report in 2013, the
consensus was for under a meter (3.3 feet) of sea level rise by
2100. In just the last few years, at least one modeling study suggests
we might need to double that.
Eric Rignot at the University of California, Irvine says that study
underscores the possible speed of ice sheet melt and collapse. "Once
these processes start to kick in," he says, "they're very fast."
The Earth has seen sudden climate change and rapid sea level rise
before. At the end of the planet's last glaciation, starting about
14,000 years ago, sea levels rose by more than 13 feet a century as
the huge North American ice sheet melted.
Greenland is losing some 200 billion tons of ice each year. That rate
doubled from the 1900s to the 2000s.
But researchers are hesitant about predicting similarly rapid climate
shifts in our future given the huge stakes involved: The rapid
collapse of today's polar ice sheets would erase densely populated
parts of our coastlines.
"Today, we're struggling with 3 millimeters [0.1 inch] per year [of
sea level rise]," says Robert DeConto at the University of
Massachusetts-Amherst, co-author of one of the more sobering new
studies. "We're talking about centimeters per year. That's really
tough. At that point your engineering can't keep up; you're down to
demolition and rebuilding."
Antarctica and Greenland hold the overwhelming majority of the world's
ice: Ninety percent of the planet's freshwater ice is locked up in
Antarctica's ice cap and nine percent in Greenland's. Today, the ice
sheet that's inarguably melting fastest is Greenland. That giant block
of ice, which has the potential to raise global sea levels by 23 feet
if it melts in its entirety, is losing some 200 billion tons of ice
each year. That rate has doubled from the 1900s to the 2000s.
"We are seeing changes in Greenland in all four corners, even in the
far north," says Rignot. Many of the outlet glaciers that flow down
fjords into the sea, which were "on the fence" about retreating or
advancing over the past decade, are now "starting to fall apart," he
says.
Danish Meteorological Institute
<Loading Image...
>Illustration of the rapid expansion of ice melt on Greenland over just
two days in April 2016.
And they're moving fast. "The flow speeds we talk about today would
have been jaw-dropping in the 1990s," says Ted Scambos of the
University of Colorado's National Snow and Ice Data
Center. Greenland's Jakobshavn Glacier dumped ice into the sea at the
astonishing rate of 150 feet per day in the summer of 2012. The most
dramatic action in Greenland is simply from surface melting, as
temperatures there and across the Arctic have soared in the last four
decades. In 2012, Greenland lost a record 562 billion tons of ice as
more than 90 percent of its surface melted in the summer sun.
Many questions remain about the physics of Greenland's ice loss, such
as whether meltwater gets soaked up by a `sponge' of snow and ice, or
trickles down to lubricate the base of the ice sheet and speed its
seaward movement. Most modeling work has been about how Greenland's
melt tracks rising air temperatures; far less is known about how
warming waters might eat away at the edges of its ice sheet. Rignot is
part of a team now launching the Oceans Melting Greenland project
(with the intentionally punny acronym OMG) to investigate that. These
uncertainties make Rignot think that estimates of Greenland's melt -
contributing as much as 9 inches of global sea level rise by 2100,
according to the 2013 IPCC report - have been far too
conservative. Assuming that the Greenland ice sheet's demise "will be
slow is wishful thinking," Rignot says.
But most scientists say there shouldn't be too many serious surprises
about the physics governing Greenland's ice loss. Although the ice
sheet can be expected to steadily melt in the face of rising
temperatures, Greenland's ice cap shouldn't rapidly collapse, because
most of its ice sits safely on rock far above sea level. "Greenland is
more predictable and straightforward," says DeConto.
For fear of rapid, runaway collapse, the research community turns its
eyes south.
Antarctica is, for now, losing ice more slowly than Greenland. The
latest data from the GRACE project - twin satellites that measure mass
using gravity data - say Antarctica is losing about 92 billion tons of
ice per year, with that rate having doubled from 2003 to 2014.
The sizeable western half of Antarctica holds some of the
fastest-warming areas on the planet.
But Antarctica is vast - 1.5 times the size of the United States, with
ice three miles thick in places - and holds enough ice to raise global
sea levels by roughly 200 feet.
The larger, eastern half lies mostly above sea level and remains very
cold; researchers have typically considered its ice stable, though
even that view is beginning to change. The sizeable western half of
the Antarctic, by contrast, has its base lying below sea level, and
holds some of the fastest warming areas on the planet. "You look at
West Antarctica and you think: How come it's still there?" says
Rignot.
Warming ocean water licking at the underside of the floating edges of
the Western Antarctic Ice Sheet is eating away at the line where the
ice rests on solid rock. Much of the bedrock of the Antarctic slopes
downward toward the center of the continent, so as the invading water
flows downhill it seeps further and further inland, causing
ever-larger chunks of glaciers to flow faster into the sea. This
so-called "grounding line" has been eroding inland rapidly, in some
parts of West Antarctica at rates of miles per year. In 2014,
satellite radar images revealed just how vulnerable five massive
glaciers flowing into the Admundsen Sea are from this effect. And a
2015 paper showed that the same thing is happening more slowly to
Totten Glacier, one of the biggest glaciers in the east.
Such dramatic processes have been the bane of Antarctic modeling and
the reason why scientists have been loathe to put a number on sea
level contributions from a melting southern continent. Then in March
came a report in Nature that some say represents a step change in our
ability to do that. DeConto and David Pollard of Pennsylvania State
University put into their ice sheet model two basic phenomena:
meltwater trickling down to lubricate glacier flow, and giant walls of
ice (created when the ends of glaciers snap off) simply collapsing
under their own weight. These new modeling parameters gave DeConto and
Pollard a better understanding of past sea level rise events. For the
Pliocene era 3 million years ago, for example - when seas were dozens
of feet higher than today - older models estimated that a partially
melting Antarctic added about 23 feet to global sea level rise. The
new model increased Antarctica's contribution to sea level rise during
the Pliocene to 56 feet.
<Loading Image...
>Satellite image showing sediment plumes from meltwater exiting
glaciers in Greenland.
Turning their model to the future, DeConto and Pollard project more than
three feet of sea level rise from Antarctica alone by 2100 - assuming
growing greenhouse gas emissions that boost the planet's temperature by
about 4 degrees C (7 degrees F). That is far more than the last IPCC
estimate in 2013, which projected less than eight inches of sea level rise
from a melting Antarctic by 2100, with a possibility for inches more from
the dramatic collapse of Antarctic glaciers.
Even DeConto admits that, under the model used in his paper, the timing and
pace of Antarctica's ice loss is "really uncertain" - it could be a decade
or two, or three or four, before these dramatic processes start to kick in,
he says. "The paper just shows the potentials, which are really big and
really scary," says DeConto. But Scambos and other observers call DeConto's
numbers "perfectly plausible."
Researchers could better pin down their models if they could track the rate
of sea level rise from polar ice sheet collapse in the past, but this has
proven hard to do. When seas rose a whopping 13 feet per century at the end
of the last glaciation (the current record-holder for known rates of sea
level rise in the past), much of the water came from an ice sheet over North
America, where there isn't one today. "I wouldn't use that as an analogue
for the future," says paleo-geologist Andrea Dutton of the University of
Florida, who wrote a recent review of past records of sea level rise. "But
it has important lessons for us nonetheless - that ice sheets can retreat
suddenly and in steps instead of gradually."
For a better analogue of what's going on today, researchers often look to
the last interglacial period, about 120,000 years ago, when temperatures
were about a degree warmer than pre-industrial levels and seas were 20 to 30
feet higher than today. Ice cores from Greenland have suggested that much of
that water must have come from the Antarctic. To find out just how fast sea
levels rose at that time, Dutton is now looking at old corals in Mexico,
Florida, and Australia; corals can be used to track sea level, since they
grow in shallow waters to capture sunlight.
--
Tesla Just Made Its Huge Model 3 Challenge Even Huger
WIRED, 05 May 2016 18:30Z
Elon Musk moved his desk. He now sits at the end of the production line at
Tesla Motors' factory in Fremont, California, and he's stashed a sleeping
bag in a nearby conference room.
Opinion:Tesla investors better be ready for wild ride -- CNBC
In Depth:Elon Musk Keeps Promising the Impossible. I Think I Know Why.
-- Slate Magazine
Winnipeg weather record set with 33-degree scorcher
CBC.ca, 05 May 2016 19:25Z
Winnipeg set a hot weather record on Thursday, when the mercury climbed to
33.2 C before 2 p.m.. The previous warm weather record for May 5 was set in
1926, when it was 31.7 C. The heat wave won't last long, though;
temperatures are expected to fall ...
Winnipeg hits 33 C, previous warm-weather record for May 5 was 31.7 C
CBC.ca, 05 May 2016 20:21Z
Manitoba broke 22 hot weather records Thursday, with the mercury climbing to
34.9 C in Winnipeg alone, making it the warmest place in Canada.
Alberta Declares State Of Emergency As Thousands Flee Massive Wildfire
ClimateProgress, 06 May 2016 8:18am
The Canadian province of Alberta declared a state of emergency Wednesday as
88,000 people in the city of Fort McMurray were forced to flee a fast-moving,
immense wildfire. The blaze has already destroyed 1,600 buildings, including
a school...
cold, rainy weather welcome after Tasmania's driest April on record
ABC Online, 05 May 2016 22:22Z
This week's rain has come with dam levels at 13 per cent after the driest
April on record. Hydro Tasmania has been drawing heavily on its storages
while the disabled Basslink electricity interconnector was not able to
import power.
'Armored Closet' Offers Tornado Safety Inside Your Home
CBS Local, 06 May 2016 03:23Z
Fort Worth (CBSDFW.COM). Depending on the home, it can be a challenge to
find a "safe-spot" during a tornado warning in North Texas.
More corals die in northern Great Barrier Reef
[Image] Coral bleached white in shallow waters off Lizard Island in the
Great Barrier Reef
ABC News, 06 May 2016 07:02Z
More coral has bleached and died in the northern section of the Great
Barrier Reef in the past month, new surveys reveal.