The Present Threat to Coastal Cities From Antarctic and Greenland Melt

GR: With rising global temperature and increasing threat of rapid glacial melt, Scribbler concludes:

“The only way to lower this risk [coastal city inundation] is to rapidly reduce to zero the amount of carbon hitting the atmosphere from human sources while ultimately learning how to pull carbon out of the atmosphere. The present most rapid pathway for carbon emissions reductions involves an urgent build-out of renewable and non-carbon based energy systems to replace all fossil fuels with a focus on wind, solar, and electrical vehicle economies of scale and production chains. Added to various drives for sustainable cities and increasing efficiency, such a push could achieve an 80 percent or greater reduction in carbon emissions on the 2-3 decade timescale with net negative carbon emissions by mid Century. For cities on the coast, choosing whether or not to support such a set of actions is ultimately an existential one.” –RobertScribbler (The Present Threat to Coastal Cities From Antarctic and Greenland Melt | robertscribbler)

Sea-Level Rise: Bubble, Bubble, GigaTons of Methane Trouble | Paul Beckwith

Methane and Sea-Level Rise

GR: Climate Scientist, Professor Paul Beckwith, who you may know from his frequent YouTube posts, believes that current climate-change model predictions of sea-level rise make incorrect assumptions and dramatically underestimate rise.

Beckwith has convincingly argued that all the positive feedbacks, especially from exponential increase in methane released by warming sea floors and melting permafrost will increase sea level by seventy feet by 2070. This is about 68 feet more than the model predictions that motivated the Paris Accord.

Let me repeat my warning that if we don’t act immediately, the climate-change equivalent of an approaching fire storm will reach us soon. We are approaching (and might have passed) that point on our roller coaster ride when we inch over the crest and begin our unstoppable acceleration toward the bottom–a bottom where the rails end. Talk, petition, write, call, march, and vote.

Beckwith provides clear discussions of global warming. I recommend you subscribe to his YouTube channel. Here are some of Dr. Beckwith’s recent videos and discussions.

“Vast amounts of methane exists within ocean floor sediments on the Eastern Siberian Arctic Shelf, in the form of methane hydrates & free methane gas.

“Up to recently, gas release to the shallow water column (50 meters deep) and atmosphere has been slow, with the subsea permafrost acting as a million corks on a million champagne bottles to contain the methane.

“Now, rapid thawing of the permafrost has released 10% of the corks, allowing rapid ongoing increases in methane release.

–Paul Beckwith (Bubble, Bubble, GigaTons of Methane Trouble | Paul Beckwith, Climate System Scientist)

Antarctica Is Melting, and Giant Ice Cracks Are Just the Start

GR: Glaciers are melting at the North Pole, the South Pole, and in mountains around the planet. Sea level is rising. If we stop adding greenhouse gasses to the atmosphere now, melting might stop within a few centuries. At that point, sea level will be more than 30 feet higher than it is now. If we continue to add greenhouse gasses to the atmosphere, we can expect 70 feet of sea-level rise before stability is reached. Stability at that point will occur because we will have stopped producing greenhouse gases–we will have little working technology left. Cutting emissions immediately is the only way we might limit the rise to 30 feet.

In East Antarctica, Australian researchers probe for crevasses on Totten Glacier—another one that has begun to look vulnerable—before deploying instruments to measure how fast it’s moving and thinning (photo by Camille Seaman).

As you will see as you read this article, critical measurements are underway to determine how fast the ice is melting. It is expensive to make the measurements that will give us the ability to predict and plan for rising sea level. Less money than presidential trips to Florida to play golf, but substantial amounts nevertheless. This is just the type of necessary spending the Trump administration (actually the corporatists controlling Congress) is intent on ending. Isn’t this a crime against nature and humanity?

Melting Antarctic Glaciers

(The following story appears in the July 2017 issue of National Geographic Magazine.)

“The massive iceberg poised to break off the Larsen C Ice Shelf may be a harbinger of a continent-wide collapse that would swamp coastal cities around the world.

“Seen from above, the Pine Island Ice Shelf is a slow-motion train wreck. Its buckled surface is scarred by thousands of large crevasses. Its edges are shredded by rifts a quarter mile across. In 2015 and 2016 a 225-square-mile chunk of it broke off the end and drifted away on the Amundsen Sea. The water there has warmed by more than a degree Fahrenheit over the past few decades, and the rate at which ice is melting and calving has quadrupled.

“On the Antarctic Peninsula, the warming has been far greater—nearly five degrees on average. That’s why a Delaware-size iceberg is poised to break off the Larsen C Ice Shelf and why smaller ice shelves on the peninsula have long since disintegrated entirely into the waters of the Weddell Sea. But around the Amundsen Sea, a thousand miles to the southwest on the Pacific coast of Antarctica, the glaciers are far larger and the stakes far higher. They affect the entire planet.

A startling sunset reddens the Lemaire Channel, off the west coast of the Antarctic Peninsula. The continent’s coastal ice is crumbling as the sea and air around it warm (photo by Camille Seaman).

 

“These are the fastest retreating glaciers on the face of the Earth,” says Eric Rignot, a glaciologist at the NASA Jet Propulsion Laboratory in Pasadena, California. Rignot has studied the region for more than two decades, using radar from aircraft and satellites, and he believes the collapse of the West Antarctic Ice Sheet is only a matter of time. The question is whether it will take 500 years or fewer than a hundred—and whether humanity will have time to prepare.

“We have to get these numbers right,” Rignot says. “But we have to be careful not to waste too much time doing that.”

“Getting the predictions right requires measurements that can be made only by going to the ice. In December 2012 a red-and-white Twin Otter plane skimmed low over the Pine Island Ice Shelf. The pilot dragged the plane’s skis through the snow, then lifted off and circled back to make sure he hadn’t uncovered any crevasses. After the plane landed, a single person disembarked. Tethered to the plane by a rope and harness, he probed the snow with an eight-foot rod.” –Douglas Fox–Photographs by Camille Seaman. (This story appears in the July 2017 issue of National Geographic magazine. Continue: Antarctica Is Melting, and Giant Ice Cracks Are Just the Start.)

The west side of the Antarctic Peninsula is warming several times faster than the rest of the planet. Ninety percent of its 674 glaciers are now in retreat and are calving more icebergs into the sea, like this one in Andvord Bay (photo by Camille Seaman).

New study finds the oceans are rising three times faster than they were during the 20th century

GR: Coastal flooding as global warming melts the polar ice caps is one of the most devastating consequences of human-caused climate change. Years ago, scientists predicted that at some point, the rate of sea level rise would accelerate. We have now passed that point. According to NOAA, “nuisance flooding” is already becoming a problem on the U. S. east coast where high tides will be higher than many other places on the globe. Here’s a story on what scientists expect. You will notice that global annual averages are small. However, when you consider totals for decades, and when you consider that the totals will be much higher in some areas like the U. S. east coast, you can see how great the threat is.

An iceberg is pictured in the western Antarctic peninsula in March 2016. (Eitan Abramovich/AFP/Getty Images)

“A new scientific analysis finds that the Earth’s oceans are rising nearly three times as rapidly as they were throughout most of the 20th century, one of the strongest indications yet that a much feared trend of not just sea level rise, but its acceleration, is now underway.

“We have a much stronger acceleration in sea level rise than formerly thought,” said Sönke Dangendorf, a researcher with the University of Siegen in Germany who led the study along with scientists at institutions in Spain, France, Norway and the Netherlands.

“Their paper, just out in the Proceedings of the National Academy of Sciences, isn’t the first to find that the rate of rising seas is itself increasing — but it finds a bigger rate of increase than in past studies. The new paper concludes that before 1990, oceans were rising at about 1.1 millimeters per year, or just 0.43 inches per decade. From 1993 through 2012, though, it finds that they rose at 3.1 millimeters per year, or 1.22 inches per decade.

“The cause, said Dangendorf, is that sea level rise throughout much of the 20th century was driven by the melting of land-based glaciers and the expansion of seawater as it warms, but sea level rise in the 21st century has now, on top of that, added in major contributions from the ice sheets of Greenland and Antarctica.

“The sea level rise is now three times as fast as before 1990,” Dangendorf said.

–Chris Mooney, More: New study finds the oceans are rising three times faster than they were during the 20th century – The Washington Post