Antarctic ice melt accelerating

One of the fears of global warming was that past a ‘tipping point’ the warming and the effects of the warming could accelerate. A report suggests this could be happening.

DW: Rate of Antarctic ice melt triples since 2012, study finds

The rate of ice loss in Antarctica has tripled since 2012, causing global sea levels to rise at their fastest rate in 25 years, a new study published by an international team of experts said Wednesday

Over the last quarter century, about 3 trillion tons of Antarctic ice melt made ocean levels rise by 7.6 millimeters (0.3 inches), according to the study published in the journal Nature.  About two-fifths of that rise, or 3 millimeters, has occurred since 2012.

The study of Antarctic ice mass changes by scientists working for NASA and the European Space Agency is the most comprehensive to date. It combined 24 satellite surveys and involved 80 scientists from 42 international organizations.

The study found that from 1992 to 2011, Antarctica lost about 83.8 billion tons (76 billion metric tons) of ice per year, causing an annual sea level rise of 0.2 millimeters. Between 2012 and 2017, ice loss per year tripled to 241.4 billion tons, amounting to a 0.6 millimeters sea level rise per year.

“Under natural conditions we don’t expect the ice sheet to lose ice at all,” said lead author Andrew Shepherd of the University of Leeds in England. “There are no other plausible signals to be driving this other than climate change.”

Scientists said much of the retreating ice shelf is caused by ocean-induced melting, when warmer water causes melting from the edges and below ice sheets.

No doubt some will continue to argue against ‘climate change’ but evidence suggests that is increasingly untenable.

The signs look increasingly ominous.

Stuff:  ‘Grim future’ on the horizon as Antarctic ice melt triples

Scientists are uncertain whether this acceleration will continue at the same rate but fear unless political decisions are made to protect Antarctica the results could be catastrophic.

Sea level contribution due to the Antarctic ice sheet between 1992 and 2017, from data gathered by international ...

Better understanding in recent years about ice loss means they now also believe that if greenhouse gas emissions continue to increase as they have done in the past, sea levels could rise by up to two metres by the end of the century – double the previous estimates – putting half a billion lives at risk.

Professor Tim Naish, of the Victoria University of Wellington, who contributed to the study, said the scenario had “sent shockwaves around the world” and painted a “grim future”.

But he said there is still hope if there is concerted global collaboration to tackle global warming.

“There is still time to prevent major meltdown of the ice sheets, and other far-reaching dangerous impacts if nations collectively reduce their emissions in line with the Paris Climate Agreement target of 2C warming above pre-industrial levels,” he said.

“I think the acceleration from Antarctica represents the beginning of the effect on the ocean, which we haven’t seen until about a decade ago.

“But there is still a very valid question as to how we predict that into the future, and whether we can keep that acceleration going for 100 years or whether that part of Antarctica will stabilise a little bit and things will slow down.”

A one to two metre rise in sea levels by the end of this century would have major implications for places like Dunedin, Christchurch, Wellington, Tauranga and Auckland.

There are already issues with the current sea level. ODT: Edgar Centre warped by subsidence

Dunedin’s Edgar Centre sports complex is being lifted and lowered by the tide, as water strips away sand and leaves voids in the reclaimed land beneath the complex, reports show.

…they also showed the entire complex was being warped by subsidence, having dropped by up to 1m, and being affected by the tide as water washed through the sedimentary layers of reclaimed land the venue was built on.

And ‘Bill’ raises a valid concern at The Standard in Let’s Build a Hospital! – they are planning to build a new hospital in Dunedin on reclaimed land, but new buildings – like the stadium, have foundation piles driven down to solid rock.

How much of a rise would be needed to cut Auckland off from New Zealand? It probably isn’t the biggest issue there if the sea rises a metre or two.

Other parts of the world have much bigger worries if they take the increasing amount of scientific evidence seriously.

 

Global sea level rise “accelerating a little every year”

Griff on sea level rise:


Research team detects an acceleration in the 25-year satellite sea level record:

Global sea level rise is not cruising along at a steady 3 mm per year, it’s accelerating a little every year, like a driver merging onto a highway, according to a powerful new assessment led by CIRES Fellow Steve Nerem. He and his colleagues harnessed 25 years of satellite data to calculate that the rate is increasing by about 0.08 mm/year every year—which could mean an annual rate of sea level rise of 10 mm/year, or even more, by 2100.

“This acceleration, driven mainly by accelerated melting in Greenland and Antarctica, has the potential to double the total sea level rise by 2100 as compared to projections that assume a constant rate—to more than 60 cm instead of about 30.” said Nerem, who is also a professor of Aerospace Engineering Sciences at the University of Colorado Boulder. “And this is almost certainly a conservative estimate,” he added. “Our extrapolation assumes that sea level continues to change in the future as it has over the last 25 years. Given the large changes we are seeing in the ice sheets today, that’s not likely.”.

Read more at: https://phys.org/news/2018-02-team-year-satellite-sea.html#jCp

U.S. Climate Envoy Jonathan Pershing: Five Feet Of Sea Level Rise By 2050 Possible
The mood in Marrakech was somber when top climate envoy for President Barack Obama Jonathan Pershing dropped a bombshell on observers gathered there: The rapid warming in polar regions the world is now witnessing may result in five feet—or 1.5 meters— of sea level rise by 2050.
https://www.huffingtonpost.com/daphne-wysham/us-climate-envoy-jonathan_b_13070296.html

Think sea level rise will be moderate and something we can all plan for? Think again.

Sea levels could rise by much more than originally anticipated, and much faster, according to new data being collected by scientists studying the melting West Antarctic ice sheet – a massive sheet the size of Mexico.

That revelation was made by an official with the National Oceanic and Atmospheric Administration on Tuesday at the annual RIMS conference for risk management and insurance professionals in San Diego, Calif.

The conference is being attended by more than 10,000 people, according to organizers. It was day No. 3 of the conference, which ends Wednesday.

Margaret Davidson, NOAA’s senior advisor for coastal inundation and resilience science and services, and Michael Angelina, executive director of the Academy of Risk Management and Insurance, offered their take on climate change data in a conference session titled “Environmental Intelligence: Quantifying the Risks of Climate Change.”

Davidson said recent data that has been collected but has yet to be made official indicates sea levels could rise by roughly 3 meters or 9 feet by 2050-2060, far higher and quicker than current projections. Until now most projections have warned of seal level rise of up to 4 feet by 2100..

https://www.insurancejournal.com/news/national/2016/04/12/405089.htm