Antarctica: ...and still it melts

Three years to prevent climate catastrophe

Submitted by Bill Weinberg on Sat, 07/01/2017 - 03:07

The world has three years to start making significant reductions in greenhouse gas emissions or face the prospect of dangerous global warming, experts have warned in an article in the prestigious journal Nature.

Calling for world leaders to be guided by the scientific evidence rather than "hide their heads in the sand," they said "entire ecosystems" were already beginning to collapse, summer sea ice was disappearing in the Arctic and coral reefs were dying from the heat.

The world could emit enough carbon to bust the Paris Agreement target of between 1.5 to 2 degrees Celsius in anything from four to 26 years if current levels continue, the article said.

Global emissions had been rising rapidly but have plateaued in recent years. The experts, led by Christiana Figueres, who as Executive Secretary of the United Nations Framework Convention on Climate Change played a key role in the Paris Agreement, said they must start to fall rapidly from 2020 at the latest.

Note that James Hansen and others have already predicted that even with the 2 degrees Celsius lmit established by the Paris Accord that the US just abandoned, New York, London, Calcutta, Shanghai and many other cities will be flooded and basically uninhabitable within a century. If current carbon output levels continue, we'll reach 6 degrees within a century, which would likely mean human extinction. A rise of 11 degrees has been broached. (AFP, Nov. 30, 2015; Slate, July 20, 2015; CNN, May 22, 2015; WP. Nov. 28, 2011)

Disintegration of Antarctic ice shelf: it's on

Submitted by Bill Weinberg on Thu, 07/13/2017 - 03:29

Well, that crack in the Larsen C ice shelf has now cut all the way across, producing (as predicted) an iceberg about the size of the state of Delaware. The ice shelf is now 12% smaller. The new massive 'berg weighs a trillion tons and contains as much water as Lake Erie—the biggest iceberg ever recorded. The media are full of don't-worry-be-happy commentators who keep reminding us that the giant breakaway iceberg will have no impact on sea level because the ice shelf itself was already resting on the ocean. More sober voices point out that as the ice shelves deteriorate, the inland ice sheets will start sliding into the sea. If the entire West Antarctic Ice Sheet were to melt, it would raise sea levels by a devastating 15 feet. Of course this would "take centuries," so don't worry about it. Fuck posterity, right?

In 2002, an ice shelf the size of Rhode Island, the Larsen B, broke apart in two weeks...(Mashable, The Verge, NPR, Gizmodo)

Era of 'Biological Annihilation' underway

Submitted by Bill Weinberg on Thu, 07/13/2017 - 03:59

From the New York Times, July 11:

From the common barn swallow to the exotic giraffe, thousands of animal species are in precipitous decline, a sign that an irreversible era of mass extinction is underway, new research finds.

The study, published Monday in the Proceedings of the National Academy of Sciences, calls the current decline in animal populations a "global epidemic" and part of the "ongoing sixth mass extinction" caused in large measure by human destruction of animal habitats. The previous five extinctions were caused by natural phenomena.

Gerardo Ceballos, a researcher at the Universidad Nacional Autónoma de México in Mexico City, acknowledged that the study is written in unusually alarming tones for an academic research paper. "It wouldn't be ethical right now not to speak in this strong language to call attention to the severity of the problem," he said.

Dr. Ceballos emphasized that he and his co-authors, Paul R. Ehrlich and Rodolfo Dirzo, both professors at Stanford University, are not alarmists, but are using scientific data to back up their assertions that significant population decline and possible mass extinction of species all over the world may be imminent, and that both have been underestimated by many other scientists.

So here we are reading in the MSM that the sixth mass extinction is imminent or underway—the first (obviously) that is anthropogenic. This raises the question of whether we humans really are rational, conscious beings or, ultimately, a blind force of nature, like the meteor that wiped out the dinosaurs at the end of the Cretaceous...

The industrial system that is driving this planetary collapse is the fruit of rationalism. Yet its continuance is so thoroughly irrational. It's such a paradox.

Meanwhile, the oceans are dying...

Submitted by Bill Weinberg on Sat, 09/23/2017 - 03:08

As we've already noted. But PhysOrg on Sept. 20 reports the findings of Daniel Rothman, professor of geophysics at MIT, that if 310 gigatons of carbon are added to the oceans, it will trigger Planet Earth's "sixth mass extinction." This is on track to happen by 2100.

"This is not saying that disaster occurs the next day," Rothman says. "It's saying that, if left unchecked, the carbon cycle would move into a realm which would be no longer stable, and would behave in a way that would be difficult to predict. In the geologic past, this type of behavior is associated with mass extinction."

In the past 540 million years, the Earth has endured five mass extinction events, each involving processes that upended the normal cycling of carbon through the atmosphere and oceans. These globally fatal perturbations in carbon each unfolded over thousands to millions of years, and are coincident with the widespread extermination of marine species around the world.

The question for many scientists is whether the carbon cycle is now experiencing a significant jolt that could tip the planet toward a sixth mass extinction. In the modern era, carbon dioxide emissions have risen steadily since the 19th century, but deciphering whether this recent spike in carbon could lead to mass extinction has been challenging. That's mainly because it's difficult to relate ancient carbon anomalies, occurring over thousands to millions of years, to today's disruptions, which have taken place over just a little more than a century.

Now Daniel Rothman, professor of geophysics in the MIT Department of Earth, Atmospheric and Planetary Sciences and co-director of MIT's Lorenz Center, has analyzed significant changes in the carbon cycle over the last 540 million years, including the five mass extinction events. He has identified "thresholds of catastrophe" in the carbon cycle that, if exceeded, would lead to an unstable environment, and ultimately, mass extinction.

In a paper published in Science Advances, he proposes that mass extinction occurs if one of two thresholds are crossed: For changes in the carbon cycle that occur over long timescales, extinctions will follow if those changes occur at rates faster than global ecosystems can adapt. For carbon perturbations that take place over shorter timescales, the pace of carbon-cycle changes will not matter; instead, the size or magnitude of the change will determine the likelihood of an extinction event.

Taking this reasoning forward in time, Rothman predicts that, given the recent rise in carbon dioxide emissions over a relatively short timescale, a sixth extinction will depend on whether a critical amount of carbon is added to the oceans. That amount, he calculates, is about 310 gigatons, which he estimates to be roughly equivalent to the amount of carbon that human activities will have added to the world's oceans by the year 2100.

Does this mean that mass extinction will soon follow at the turn of the century? Rothman says it would take some time—about 10,000 years—for such ecological disasters to play out. However, he says that by 2100 the world may have tipped into "unknown territory."