Collapse of Greenland ice sheet to raise sea level faster than expected – Haaretz

The vast ice sheet on Greenland has become unstable and technology isnt storming to the rescue. The world is not on a trajectory to curb global warming at 1.5 degrees Celsius were almost there already. Everybody is asleep. Its like the Titanic, wails sea level rise guru John Englander, an oceanographer and author who has made it his lifes mission to shake the world awake before its too late.

Too late for what? To secure coastlines all over the world ahead of the rising sea, which is pushing coastlines farther inland. To protect property values, to strategize and reorganize economic priorities, to move seaside nuclear reactors, you name it. Life as we know it.

Part of the reason for the global somnolescence is that scientific reports by nature err on the side of caution. Thus, the current sea level rise estimates for 2050 or 2100 (which distract from the fact that sea level rise will continue afterward) are typically conservative, which in this case means they understate the real rise. Its also considered rude to conclude that the world is careening toward hell in a handbasket.

But the world is not on a minimalist trajectory. It is not heading for a mere 40-centimeter (16-inch) increase by 2100 based on the optimistic scenario, which is losing credence. The official (UN-IPCC) high end of forecasts is around 90 centimeters by 2100 but even that is too optimistic in Englanders view, as he warned in a joint paper with other academics in December: Twenty-first century sea level rise could exceed IPCC projections for strong-warming futures.

Sea level rise by 2100 could be 2 meters. It could be 3, or 4 meters, he says. The only thing we know is that we dont know: the situation is fluid, you should excuse the expression. And we know that a lot of the water will come from Greenland.

To warn the general population, however, Englander feels sciences kid gloves are inappropriate at this point. Mounting evidence indicates climate change is accelerating and creating vicious circles that quicken it even more. The destabilization of Greenlands ice sheet is a case in point.

It is hard to reconcile reports of its accelerated melting and destabilization with estimates that it will, nonetheless, take maybe five to six centuries for all Greenlands ice to melt. Englander explains this seeming incongruity.

Ive been there several times, leading expeditions, he tells Haaretz. Its hard to comprehend how vast Greenland is. Its 2,500 kilometers north to south and about 1,000 kilometers east to west, literally from east of the Mississippi in the U.S., and from Maine to Florida i.e., nearly 2.2 million square kilometers.

In Middle Eastern terms, Greenland is about the size of Saudi Arabia. (Israel is about 22,000 square kilometers in area about twice the size of B-15, the biggest-ever iceberg caught on camera, which calved off the Ross Ice Shelf. )

Greenland is covered by a layer of ice 1 to 3 kilometers thick; if it all melts, it will raise global sea levels by over 7 meters. No one thinks that can happen quickly. It will take centuries, at least. The question is what will happen by 2050 and 2100, Englander drives home the point.

Asked if the Greenlandic ice sheets recently reported destabilization could change his vague expectation that the melt should take centuries, Englander offers the only answer he can: maybe. Which is all the more reason to wake up.

Sea level rise cannot be stopped

Even if carbon dioxide emissions were to screen to a halt today, even if cows were to start farting flowers instead of methane, even if every car were to suddenly morph into a tree, further sea level rise is inevitable. Like the Titanic, its direction cannot be diverted anymore, though its momentum might be influenced.

It is time to glance again at John Englanders famous graph of historic correlations between atmospheric carbon dioxide levels, global mean temperatures, and sea level over the last 400,000 years. The graph shows exactly what the problem is:

Atmospheric carbon dioxide has risen to levels last seen millions of years ago, approximately speaking (neither Donald Trump nor the coronavirus changed the trajectory in any meaningful sense). Atmospheric carbon dioxide concentrations and temperature are correlated: if the one rises, so does the other. The higher the CO2, the higher the global mean temperature at a lag. Again: at a lag. Temperature has yet to proportionately react to the increase in carbon dioxide levels.

Yes, after CO2 rises, temperature will too but how long the reaction will take depends on a practically infinite array of parameters, so it cannot be predicted with any meaningful accuracy. All we can say is it will happen, and the fact that the globe has experienced year after year of record heat is just the start. Oceans, being vast and dense and saline, take longer to react than the air or shallow lakes, but as the air warms, so does their surface and then their depths. The Arctic has been among the worst affected there are days parts of it are hotter than in Tel Aviv.

Apropos of which, forecasting the future of Israels coast is tricky.

The coastline has moved kilometers inland over the last 50 years, says Dr. (emeritus) John K. Hall of the Geological Survey of Israel, adding that this conundrum tends to be met with massive denial. The beaches are eroding, the cliffs are coming down, he adds. At sea rise levels of 20 to 30 centimeters, it is difficult to draw lines with any accuracy, to say which neighborhoods will be affected and which spared but the key issue is the likelihood of increasingly violent storms smashing into the beaches and cliffs. If sea levels come up, storms will beat the hell out of the coast, Hall predicts.

Anyway, there is a growing unease in global scientific circles about simultaneously warning and reassuring the public. More and more scientists are warning that sea level will rise faster than previously thought. Which means what?

Forecast: Weasels?

The Greenland ice sheet alone locks up 7 meters of sea level rise, which is bad enough, but Antarctica locks up 65 meters more, Englander explains. All the other glaciers in the world add just 1 more meter. Looking at glaciers from Mount Kilimanjaro [in Kenya] to the Alps, its pocket change he says.

Ergo: the Arctic island of Greenland and southern continent of Antarctica contain about 98 percent of the ice on land, by volume. Yet modelers have been ignoring Antarcticas contribution.

This is why? For one thing, because the dynamics and precise timing of Antarcticas melting ice remain profoundly unclear. As we said, scientists tend to err on the side of caution, lest they be perceived as a pack of yowling Cassandras scorned by policymakers. If you stand on a soapbox shrieking The end is nigh, precious few will listen even as avenging angels begin to arrive.

But the result is that projections of half a meter to just-under-a-meter of sea level rise by the centurys end dont factor in Antarctica, nor do they factor in Greenlands destabilization, Englander explains.

That is bound to end about as well as the Euripides play performed in 408 B.C.E., where the actor Hegelochus meant to say, After the storm I see again a calm sea, but wound up saying, After the storm I see again a weasel. Well, 2,500 years belatedly, the unfortunate thespian may have had a point. Those are not calm seas on our horizon.

The Greenlandic irony

What does Greenland has destabilized even mean? That parts of the ice sheet and major glaciers are already exhibiting sudden break up and collapse. In 2012, the documentary Chasing Ice captured one huge collapse using time-lapse cameras. Meanwhile, Greenland is already the chief contributor to sea level rise today, and it has started to dawn on coastal residents and insurance companies and the like that something will have to be done.

Part of Englanders book due out on April 6, Moving to Higher Ground (The Science Bookshelf), discusses exactly these conundrums.

Why is it only an issue now? The science of climate change has been around for decades. Why is anybody still buying a beachside home?

Englander blames a failure of imagination. At the height of the Ice Age, the average sea level was 120 meters lower than it is now. As the latest Ice Age waned and the ice sheets melted, sea levels gradually rose sometimes more abruptly than at other times. But none of that happened during recorded history.

Civilization as we could recognize it a gradual transition from hunting-gathering to a settled lifestyle seems to have begun around 12,000 years ago, some places earlier, some places later, well after the Last Glacial Maximum 22,000 years ago. People adore living by the coast and always have. Even Neanderthals are thought to have frolicked in the water and dived for shellfish. And the first villages on low-lying shoreland were indeed inundated. Israeli archaeologists, for example, have found the remains of Neolithic villages off todays coast, under the waves of the Mediterranean.

But for the last 7,000 or 8,000 years, sea levels have been stable, near present-day heights, and we are not capable of imagining the situation otherwise, Englander postulates.

Sea levels have been creeping up since the industrial revolution began and some cities have noticed think of Miami and its sunny-day floods. But that is why we simply cannot fathom what a meter or two even mean. Its beyond our scope of experience.

The last time sea level was above present-day levels was 122,000 years ago, when it was some 7 meters above present, he explains.

Even at the accelerated warming rate, most people dont think well get more than a meter out of sea level rise from Greenland this century. But a meter of global sea level rise would be devastating, flooding literally thousands of coastal communities, he points out the obvious.

Three of the biggest cities in the world are in acute danger: Shanghai, Mumbai and Jakarta, and so are hundreds more from Alexandria to Boston to London.

Ironically, Greenlands own coastlines are probably safe. This is because as its ice cover melts, the land is rising, as land does when an enormous weight is lifted. It is the obverse of the situation in Jakarta, where the land is sinking because of groundwater depletion, the heavy buildings and sea level rise. Never mind 2100: the city is expected to be 95 percent underwater by 2050.

The human instinct is to be optimistic, [to hope] technology will come to the rescue. But it doesnt make sense in this context, Englander sums up. The oceans have been warmed almost a degree already and were going to warm them 2 degrees more. The ice is going to melt.

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Collapse of Greenland ice sheet to raise sea level faster than expected - Haaretz