A total of 24 tornadoes were reported in seven states: Tennessee, Mississippi, Illinois, Indiana, Alabama, Arkansas and Michigan. 10 people were killed in Mississippi, Tennessee and Arkansas as storms spawned rare Christmas tornadoes. A large tornado tore a 100-mile path through northern Mississippi, demolishing or heavily damaging dozens of homes and other buildings in a six-county area before plowing into western Tennessee. Officials blamed the severe weather for injuring scores of others Wednesday and destroying dozens of cars, homes and businesses. In the worst-hit communities, search parties hunted for missing people and volunteers helped clear debris on a day often reserved for gift wrapping and last-minute shopping. Unseasonably warm weather is the main cause. The National Weather Service forecast isolated severe thunderstorms from the mid-Atlantic region to the Gulf Coast and record warmth to New York.
“To have long-track tornadoes in December in the Memphis forecast area is an unusual event,” said Jonathan Howell, a meteorologist in the NWS Memphis office. "We typically don't have tornadoes of that intensity that impact the area, but we're dealing with this unusally warm weather pattern." The line of storms are moving east today (Thursday) and will bring heavy rain and thunderstorms to Georgia, Florida, Virginia, and the Carolinas. The threat of severe weather just before Christmas is unusual, but not unprecedented, said Greg Carbin, a meteorologist at the national Storm Prediction Center. Exactly a year ago, twisters hit southeast Mississippi, killing five people and injuring dozens of others.
NASA observations show the dynamism of Greenland's Ice sheet in the changing elevation of its surfaces. Recent analysis of seven years of readings from NASA's ICESat satellite and four years of laser and and ice-penetrating radar data from NASA's airborne mission Operation IceBridge shows the changes taking place.
In the animation featured below, the colors shown on the surface of the ice sheet represent the accumulated change in elevation since 2003. The light yellow over the central region of the ice sheet indicates a slight thickening due to snow. This accumulation, along with the weight of the ice sheet, pushes ice toward the coast. Thinning near coastal regions, shown in green, blue and purple, has increased over time and now extends into the interior of the ice sheet where the bedrock topography permits. As a result, there has been an average loss of 300 cubic kilometers of ice per year between 2003 and 2012.
This animation portrays the changes occurring in the surface elevation of the ice sheet since 2003 in three drainage regions: the southeast, the northeast and the Jakobshavn regions. In each region, the time advances to show the accumulated change in elevation from 2003 through 2012.
“The retreat of these glacier is likely to increase sea-level rise for decades to come, collapse of the entire basin is going to take a long time, But it’s a process, when you start, you don’t see the glacier recovering.”
Average annual surface air temperature anomaly (+1.3°C)
over land north of 60°N for October 2014-September 2015 was the highest
in the observational record beginning in 1900; this represents a 2.9°C
increase since the beginning of the 20th Century.
Average air temperature anomalies in all seasons between
October 2014 and September 2015 were generally positive throughout the
Arctic, with extensive regions exceeding +3°C relative to a 1981-2010
baseline.
Anomalously warm conditions from November 2014 through
June 2015 in Alaska were caused by weather patterns that advected warm
mid-latitude air northward from the northeast Pacific Ocean. Anomalously
warm Arctic conditions during spring (April, May, June) 2015 across
central Eurasia were also due to southerly winds.
Strong connections between the Arctic and the
mid-latitudes were also seen in late winter-early spring
(February-April) 2015, when cold air advected south-eastward from the
central Arctic resulted in major negative temperature anomalies over
eastern North America.
Melt area in 2015 exceeded more than half of the ice sheet
on July 4th for the first time since the exceptional melt events of
July 2012, and was above the 1981-2010 average on 54.3% of days (50 of
92 days).
The length of the melt season was as much as 30-40 days
longer than average in the western, northwestern and northeastern
regions, but close to and below average elsewhere on the ice sheet.
Surface air temperatures over the Arctic have climbed 5.2 degrees Fahrenheit since the beginning of the 20th Century – more than twice the level of warming experienced elsewhere on Earth, scientists said Tuesday in an annual report. Between October 2014 and September 2015, the average surface air temperature in the region was 2.3 degrees Fahrenheit higher than the baseline average set between 1981 to 2010 — the highest temperature in 115 years, said U.S. Army Corps of Engineers researcher Jackie Richter-Menge.
“In general, air temperatures in all seasons were above average throughout the Arctic, with extensive regions exceeding 5.4 degrees Fahrenheit over the 1981-2010 baseline,” Richter-Menge told reporters at the American Geophysical Union conference in San Francisco.
The warmer air contributed to changes in the amount of Arctic sea ice, which peaked on Feb. 25 – 15 days earlier than average. This winter ice pack was the smallest on record since 1979.
In addition, only 3 percent of the ice cover in February and March 2015 was so-called “old ice,” which is older than four years. New, first-year ice made up 70 percent of the pack, the research showed. Three decades ago, 20 percent of the ice pack was more than four years old and just 35 percent of the pack was first-year ice, Richter-Menge said. “Given consistent projections of continued warming temperatures, we can expect to see continued widespread and sustained change throughout the Arctic environmental system,” she added.
Greenland is loosing ice mass quite rapidly for years, as this chart indicates:
Cumulative change in the total mass (in Gigatonnes, Gt) of the
Greenland Ice Sheet between April 2002 and April 2015
The changing Arctic is impacting the rest of the planet as well, said Rick Spinrad, chief scientist with the National Oceanic and Atmospheric Administration (NOAA), which released the 2015 Arctic Report Card
“What happens in the Arctic doesn’t stay in the Arctic,” Spinrad said. “What happens matters to all of us from strategic, climate and national security perspectives.”
As the world prepares for the most important global climate summit yet in Paris later this month, news from Greenland could add urgency to the negotiations. For another major glacier appears to have begun a rapid retreat into a deep underwater basin, a troubling sign previously noticed at Greenland’s Jakobshavn Glacier and also in the Amundsen Sea region of West Antarctica. And in all of these cases, warm ocean waters reaching the deep bases of marine glaciers appears to be a major cause.
NASA’s worried that Greenland’s melting could accelerate.
The midnight sun still gleamed at 1 a.m. across the brilliant expanse of the Greenland ice sheet. Brandon Overstreet, a doctoral candidate in hydrology at the University of Wyoming, picked his way across the frozen landscape, clipped his climbing harness to an anchor in the ice and crept toward the edge of a river that rushed downstream toward an enormous sinkhole. Mr. Overstreet’s task is to collect critical data from the river, and is essential to understanding one of the most consequential impacts of global warming. The scientific data he and a team of six other researchers collect here could yield groundbreaking information on the rate at which the melting of the Greenland ice sheet, one of the biggest and fastest-melting chunks of ice on Earth, will drive up sea levels in the coming decades. The full melting of Greenland’s ice sheet could increase sea levels by about 20 feet.
“We scientists love to sit at our computers and use climate models to make those predictions,” said Laurence C. Smith, head of the geography department at the University of California, Los Angeles, and the leader of the team that worked in Greenland this summer. “But to really know what’s happening, that kind of understanding can only come about through empirical measurements in the field.”
For years, scientists have studied the impact of the planet’s warming on the Greenland and Antarctic ice sheets. But while researchers have satellite images to track the icebergs that break off, and have created models to simulate the thawing, they have little on-the-ground information and so have trouble predicting precisely how fast sea levels will rise.
The new fast-moving glacier is the Zachariae glacier or Zachariæ Isstrøm, located in the far northeastern part of Greenland. In a new paper in Science, Jeremie Mouginot of the University of California-Irvine and his colleagues find that the ocean-based glacier, which contains 0.5 meters or a foot and a half of potential sea level rise, has begun a rapid retreat, especially since 2012. The glacier has lost fully 95 percent of the ice shelf that used to help stabilize it, they say, and now sports a 75 meter high ice cliff extending above the water (the glacier also extends hundreds of additional meters below it).
“This is sort of the second major floodgate from Greenland that has opened up,” says Eric Rignot of UC-Irvine and NASA’s Jet Propulsion Laboratory, one of the authors of the study. The first, says Rignot, was the Jakobshavn glacier, Greenland’s “fastest” moving, according to a recent study, which is currently based 1,300 meters below sea level and also retreating into a deep basin. Now, at Zachariae, that seems to be happening again. In combination with its nearby neighbor, Nioghalvfjerdsfjorden glacier, the two glaciers contain a potential 1.1 meter of sea level rise (over 3 feet), so any change here is not good. “If you see Greenland as a boat, it’s like we’re taking water from every side now,” says Mouginot.
Furthermore, Mouginot, Rignot and their colleagues note that Zachariae and Nioghalvfjerdsfjorden together form the terminus of the northeast Greenland ice stream, “the only large, dynamic feature that extends continuously deep to the ice sheet interior near Greenland’s summit.” Twelve percent of the entire Greenland ice sheet, they say, therefore drains through this region.
"Not long ago, we wondered about the effect on sea levels if Earth's major glaciers were to start retreating. We no longer need to wonder,"
A massive glacier in northeast Greenland has dramatically melted in the past decade and would raise global sea levels by a foot and a half if it thawed completely, according to a study published Thursday. It was a "surprise" to learn how fast the large chunk of ice was shrinking, said Jeremie Mouginot, of the University of California, Irvine, lead scientist of the report. The glacier holds enough water to raise global sea levels by more than 18 inches if it were to melt away to nothing, but no timetable exists for how long that process could take, according to the study, published in the peer-reviewed journal Science.
All by itself, it holds enough water to raise global sea level by more than 18 inches (46 centimeters) if it were to melt completely. And now it’s on a crash diet, losing 5 billion tons of mass every year. All that ice is crumbling into the North Atlantic Ocean. Just next door, there’s another melting glacier called Nioghalvfjerdsfjorden that could raise sea levels another 21 inches, totaling 39 inches globally. What does that look like, independent of any other global sea rise?
"The glacier has profoundly transformed in only 10 years," Mouginot, said. "The glacier is now breaking up and calving high volumes of icebergs into the ocean, which will result in rising sea levels for decades to come." The melting of the "Zachariae Isstrom" glacier is a result of warming temperatures both in the sea and the air, said study co-author Eric Rignot, also of UC-Irvine. "The top of the glacier is melting away as a result of decades of steadily increasing air temperatures, while its underside is compromised by currents carrying warmer ocean water, and the glacier is now breaking away into bits and pieces and retreating into deeper ground," he said.
The glacier is near a large one also melting rapidly but at a slower rate. The two chunks of ice make up 12% of the Greenland ice sheet and would boost global sea levels by more than 39 inches if they both totally collapsed, a process that would likely take centuries.
The planet's two major ice sheets are in Greenland and Antarctica, and together make up 99% of the freshwater ice on Earth, according to the National Snow and Ice Data Center. In Greenland, ice sheet decline continues to outpace accumulation, because warmer temperatures have led to increased melt and faster glacier movement at the island's edges, the data center said.
"Not long ago, we wondered about the effect on sea levels if Earth's major glaciers were to start retreating. We no longer need to wonder," Rignot said. "For a couple of decades now, we've been able to directly observe the results of climate warming on polar glaciers. The changes are staggering and are now affecting the four corners of Greenland."The entire ice sheet of Greenland contains enough ice to raise sea levels some 20 feet. It has been losing ice rapidly in recent years, through a combination of meltwater runoff on the ice sheet’s surface – which reaches the sea through complex channels and fissures — and the calving of large icebergs from its glaciers.
Both of these processes have elements that can be pretty spectacular. Atop the ice sheet, vast meltwater lakes can form and then suddenly vanish in a matter of hours, draining rapidly as crevasses open beneath them and they spill into the ice sheet’s depths. At the front ends of marine glaciers, meanwhile, detaching icebergs can tumble and slam back with such force that they knock the glacier itself backwards, and trigger magnitude 5 level earthquakes.
NASA estimates that currently, through the combination of these mechanisms, the Greenland ice sheet is losing several hundred billion tons (or gigatons) per year and raising sea levels by three quarters of a millimeter annually. If so, that would be a little under a third of the total global sea level rise, which is currently 3.24 millimeters per year.
And now, Zachariae glacier may be poised to add to that total.
From 1996 through 2010, the new research finds, Zachariae glacier’s grounding line — where the glacier simultaneously meets both the seafloor and the ocean — retreated inland 3.5 kilometers. But then from 2011 through 2015, it retreated another 3.5 kilometers, a sure sign of acceleration. A key event in letting the glacier speed up seems to have been the collapse of its ice shelf, a buttressing tongue that used to extend out over the fjord in front of the glacier, creating an underwater cavity beneath it. Now, in contrast, Zachariae is basically a steep cliff. Other ways of measuring the rate of change of the glacier — its rate of thinning, for instance, or its flow speed into the sea — were also observed to be increasing in the new study.
“This study does a nice job of putting together data from multiple sensors to document the ongoing speed up of this glacier. At present its contribution to sea level is relatively small, but there is certainly the potential for it to increase more over time,” says Ian Joughin, a Greenland and polar science expert at the University of Washington, in Seattle, in a comment on the new study. Joughin notes that thus far, despite the fast retreat, Zachariae is not losing as much ice each year as the Jakobshavn glacier in central western Greenland is losing. The new study reports a loss of 5 gigatons annually for the Zachariae glacier, or 5 billion metric tons, versus 25 to 35 gigatons for Jakobshavn, according to Joughin. Joughin thinks Zachariae may not catch up to the latter, since the basin into which it is retreating is not as deep.
But Rignot notes that with 1.1 meters of potential sea level rise between them, the Zachariae and Nioghalvfjerdsfjorden glaciers together contain about as much ice as the very worrisome glaciers along the Amundsen Sea coast of West Antarctica. Granted, in the latter case the situation is worse because losing those coastal glaciers would then unleash a bigger destabilization of West Antarctica as a whole.
Still, Greenland’s glaciers face a kind of double threat — not only changes in the ocean, but also rapidly rising Arctic temperatures, meaning that they can melt both from above and below. The key question, however — as with all studies of glacial retreats in regions with the potential to cause major sea level rise — is how much and how fast. And that’s also, of course, the hardest one to answer.
“The retreat of these marine-based sectors is likely to increase sea-level rise from Greenland for decades to come,” the paper concludes — but it does not specify how rapidly a full loss of the Zachariae glacier could occur. “Collapse of the entire basin is going to take a long time, it’s not going to happen tomorrow,” says Mouginot. “But it’s a process, when you start, it’s like Jakobshavn — [you don’t] see the glacier recovering from that.”
The hurricane is forecast to make landfall in the Mexican state of Jalisco Friday 4 PM as a Category 5 hurricane capable of causing widespread destruction. Residents and authorities in Mexico are rushing to prepare for what will likely be the strongest hurricane to ever make landfall on that country's Pacific coastline. Hurricane Patricia became the most powerful tropical cyclone ever measured in the Western Hemisphere on Friday morning as its maximum sustained winds reached an unprecedented 200 mph (320 kph).
Hurricane Patricia now also holds the record for lowest pressure in any hurricane on record. With a minimum central pressure of 880 millibars . Patricia among the most rapidly intensifying tropical cyclones ever witnessed anywhere in the world since the advent of modern meteorology.
The U.S. National Hurricane Center predicted the Category 5 Hurricane Patricia would make a "potentially catastrophic landfall" in southwestern Mexico later in the day. Tens of thousands of people were being evacuated Friday from Mexico's Pacific coast as the strongest hurricane ever recorded in the Western Hemisphere bore down on the popular tourist area packing sustained winds of 190 mph, down from 200 mph earlier in the day.
Global Sea Level rise to put dozens of cities in danger of flooding.
New Orleans, New York City, Miami, Boston, Long Beach, San Francisco, and dozens of coastal U.S. cities are doomed to be washed away by ever-rising sea levels, according to findings from a new study published in the Proceedings of the National Academy of Sciences. Fourteen cities with more than 100,000 residents each could avoid this fate in this century, including Jacksonville, Florida; Chesapeake, Virginia; and large areas of the San Joquien Valley in California, including Sacramento and Stockton.
Scientists have already established that if we do nothing to reduce our burning of fossil fuels, the planet will face sea level rise of 4.3m to 9.9m, said the study's lead author Ben Strauss, "Some of this could happen as early as next century," Dr Strauss said, "But it also might take many centuries. Just think of a pile of ice in a warm room. You know it is going to melt, but it is harder to say how quickly."
"Some cities appear to be already lost. For New Orleans, there are levees, it's possible to build levees higher and stronger for some time, but that's not necessarily safe or sustainable in the long run. We've already seen what can happen when levees break, when the sea level gets higher, the bigger the tragedy can be."
If carbon emissions are not put in check by the year 2100, the sea level could increase at least 14 feet. That would impact about 20 million people who live along the country's coast, Strauss' research found. In danger are as many as 1,800 municipalities, including 21 cities with more than 100,000 residents each.
An online tool shows which US cities may face "lock-in dates beyond which the cumulative effects of carbon emissions likely commit them to long-term sea-level rise that could submerge land under more than half of the city's population". "Norfolk, Virginia, for example, faces a lock-in date of 2045 under a scenario of unabated carbon emissions," the study says. For cities such as Miami and New Orleans, the limits are already exceeded. "In our analysis, a lot of cities have a future that depends on our carbon choices but some appear to be already lost," Dr Strauss said.
Sea level rise has been mostly measured in inches in the past decades, but scientists said they could increase more than 20 feet in the future as global warming continues to melt ice sheets in Greenland and Antarctica.
The dire projections are based on a look back at the climate record, with scientists finding that increases of 20 feet have happened at least twice over the past 3 million years when temperatures were very similar to what they are today. "Studies have shown that both the Greenland and Antarctic ice sheets contributed significantly to this sea level rise above modern levels," Anders Carlson, an Oregon State University glacial geologist and paleoclimatologist, and co-author on the study that was published Thursday in Science, said.
"Modern atmospheric carbon dioxide levels are today equivalent to those about 3 million years ago, when sea level was at least 6 meters higher because the ice sheets were greatly reduced," he said. "It takes time for the warming to whittle down the ice sheets but it doesn't take forever. There is evidence that we are likely seeing that transformation begin to take place now."
