Scientists: Human activity has pushed Earth beyond four of nine ‘planetary boundaries’

via The Washington Post


At the rate things are going, the Earth in the coming decades could cease to be a “safe operating space” for human beings. That is the conclusion of a new paper published Thursday in the journal Science by 18 researchers trying to gauge the breaking points in the natural world.

The paper contends that we have already crossed four “planetary boundaries.” They are the extinction rate; deforestation; the level of carbon dioxide in the atmosphere; and the flow of nitrogen and phosphorous (used on land as fertilizer) into the ocean.

“What the science has shown is that human activities — economic growth, technology, consumption — are destabilizing the global environment,” said Will Steffen, who holds appointments at the Australian National University and the Stockholm Resilience Center and is the lead author of the paper.

These are not future problems, but rather urgent matters, according to Steffen, who said that the economic boom since 1950 and the globalized economy have accelerated the transgression of the boundaries. No one knows exactly when push will come to shove, but he said the possible destabilization of the “Earth System” as a whole could occur in a time frame of “decades out to a century.”

The researchers focused on nine separate planetary boundaries first identified by scientists in a 2009 paper. These boundaries set theoretical limits on changes to the environment, and include ozone depletion, freshwater use, ocean acidification, atmospheric aerosol pollution and the introduction of exotic chemicals and modified organisms.

Beyond each planetary boundary is a “zone of uncertainty.” This zone is meant to acknowledge the inherent uncertainties in the calculations, and to offer decision-makers a bit of a buffer, so that they can potentially take action before it’s too late to make a difference. Beyond that zone of uncertainty is the unknown — planetary conditions unfamiliar to us.

“The boundary is not like the edge of the cliff,” said Ray Pierrehumbert, an expert on Earth systems at the University of Chicago. “They’re a little bit more like danger warnings, like high-temperature gauges on your car.”

Pierrehumbert, who was not involved in the paper published in Science, added that a planetary boundary “is like an avalanche warning tape on a ski slope.”

The scientists say there is no certainty that catastrophe will follow the transgression of these boundaries. Rather, the scientists cite the precautionary principle: We know that human civilization has risen and flourished in the past 10,000 years — an epoch known as the Holocene — under relatively stable environmental conditions.

No one knows what will happen to civilization if planetary conditions continue to change. But the authors of the Science paper write that the planet “is likely to be much less hospitable to the development of human societies.”

The authors make clear that their goal is not to offer solutions, but simply to provide information. This is a kind of report card, exploiting new data from the past five years.

It’s not just a list of F’s. The ozone boundary is the best example of world leaders responding swiftly to a looming environmental disaster. After the discovery of an expanding ozone hole caused by man-made chemicals, chlorofluorocarbons, the nations of the world banned CFCs in the 1980s.

This young field of research draws from such disciplines as ecology, geology, chemistry, atmospheric science, marine biology and economics. It’s known generally as Earth Systems Science. The researchers acknowledge the uncertainties inherent in what they’re doing. Some planetary boundaries, such as “introduction of novel entities” — CFCs would be an example of such things — remain enigmatic and not easily quantified.

Better understood is the role of carbon dioxide as a greenhouse gas. The safe-operating-zone boundary for CO2 had previously been estimated at levels up to 350 parts per million. That’s the boundary — and we’re already past that, with the current levels close to 400 ppm, according to the paper. That puts the planet in the CO2 zone of uncertainty that the authors say extends from 350 to 450 ppm.

At the rate CO2 is rising — about 2 ppm per year — we will surpass 450 ppm in just a couple of decades, said Katherine Richardson, a professor of biological oceanography at the University of Copenhagen in Denmark and a co-author of the new paper.

Humanity may have run into trouble with planetary boundaries even in prehistoric times, said Richard Alley, a Penn State geoscientist who was not part of this latest research. The invention of agriculture may have been a response to food scarcity as hunting and gathering cultures spread around, and filled up, the planet, he said. “It’s pretty clear we were lowering the carrying capacity for hunter-gatherers 10,000 years ago,” Alley said.

There are today more than 7 billion people, using an increasing quantity of resources, turning forest into farmland, boosting the greenhouse gases in the atmosphere and driving other species to extinction. The relatively sudden efflorescence of humanity has led many researchers to declare that this is a new geological era, the human age, often referred to as the Anthropocene.

The Earth has faced shocks before, and the biosphere has always recovered. Hundreds of millions of years ago, the planet apparently froze over — becoming “Snowball Earth.” About 66 million years ago, it was jolted by a mountain-sized rock from space that killed half the species on the planet, including the non-avian dinosaurs. Life on Earth always bounced back. “The planet is going to take care of itself. It’s going to be here,” Richardson said.

“There’s a lot of emotion involved in this. If you think about it, the American ethic is, ‘The sky’s the limit.’ And here you have people coming on and saying, no it isn’t, the Earth’s the limit,” she said.

Technology can potentially provide solutions, but innovations often come with unforeseen consequences. “The trends are toward layering on more and more technology so that we are more and more dependent on our technological systems to live outside these boundaries,” Pierrehumbert said. “. . . It becomes more and more like living on a spaceship than living on a planet.”

Astronomers may have found giant alien 'megastructures' orbiting star near the Milky Way

via The Independent

A large cluster of objects in space look like something you would "expect an alien civilization to build", astronomers have said. 

Jason Wright, an astronomer from Penn State University, is set to publish a report on the “bizarre” star system suggesting the objects could be a “swarm of megastructures”, according to a new report.

"I was fascinated by how crazy it looked," Wright told The Atlantic. "Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilisation to build."

The snappily named KIC 8462852 star lies just above the Milky Way between the constellations Cygnus and Lyra. It first attracted the attention of astronomers in 2009 when the Kepler Space Telescope identified it as a candidate for having orbiting Earth-like planets.

But KIC 8462852 was emitting a stranger light pattern than any of the other stars in Kepler’s search for habitable planets.

Kepler works by analysing light from distant places in the universe — looking for changes that take place when planets move in front of their stars. But the dip in starlight from KIC 8462852 doesn't seem to be the normal pattern for a planet.

Tabetha Boyajian, a postdoc at Yale told The Atlantic: “We’d never seen anything like this star. It was really weird. We thought it might be bad data or movement on the spacecraft, but everything checked out.”

In 2011 the star was flagged up again by several members of Kepler’s “Planet Hunters” team – a group of ‘citizen scientists’ tasked with analysing the data from the 150,000 stars Kepler was watching.

The analysts tagged the star as “interesting “ and “bizarre” because it was surrounded by a mass of matter in tight formation.

This was consistent with the mass of debris that surrounds a young star just as it did with our sun before the planets formed. However this star wasn’t young and the debris must have been deposited around it fairly recently or it would have been clumped together by gravity – or swallowed by the star itself.

Boyajian, who oversees the Planet Hunters project, recently published a paper looking at all the possible natural explanations for the objects and found all of them wanting except one – that another star had pulled a string of comets close to KIC 8462852. But even this would involve an incredibly improbable coincidence.

That’s when Wright, the astronomer from Penn State University and his colleague Andrew Siemion, the Director of SETI (Search for Extra-Terrestrial Intelligence) got involved. Now the possibility that the objects were created by intelligent creatures is being taken very seriously by the team.

As civilisations become more technologically advanced, they create new and better ways of collecting energy — with the end result being the harnessing of energy directly from their star. If the speculation about a megastructure being placed around the star system is correct, it could for instance be a huge set of solar panels placed around the star, scientists say.

The three astronomers want to point a radio dish at the star to look for wavelengths associated with technological civilisations. And the first observations could be ready to take place as early as January, with follow-up observations potentially coming even quicker.

“If things go really well, the follow-up could happen sooner,” Wright told The Atlantic. “If we saw something exciting… we’d be asking to go on right away.”

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