Stability of planet compromised; Human activity has pushed Earth beyond 4 of 9 planetary boundaries

 

Almost half of the processes that are crucial to maintaining the stability of the planet have become dangerously compromised by human activity. …Credit: © daizuoxin / Fotolia

 

Nearly half the systems crucial to stability of planet compromised

January 15, 2015

 

Almost half of the processes that are crucial to maintaining the stability of the planet have become dangerously compromised by human activity. That is the view of an international team of 18 researchers who provide new evidence of significant changes in four of the nine systems which regulate the resilience of the Earth. One of the systems which has been seriously affected is the nitrogen-phosphorus cycle which is essential to all life, and is particularly important to both food production and the maintenance of clean water.

 

“People depend on food, and food production depends on clean water,” says Prof. Elena Bennett from McGill’s School of the Environment who contributed the research on the nitrogen-phosphorus cycle to the study. “This new data shows that our ability both to produce sufficient food in the future and to have clean water to drink and to swim in are at risk.” The research fixing new planetary boundaries (which represent thresholds or tipping points beyond which there will be irreversible and abrupt environmental change) was published today in the journal Science. It suggests that changes to the Earth’s climate, biosphere integrity (a concept covering loss of biodiversity and species extinction), and land-system (through deforestation for example) represent a risk for current and future societies. The fourth process which has become significantly compromised is the nitrogen-phosphorus cycle, which affects both the water we drink and our ability to produce food….

Key points:

  • The concept of planetary boundaries has been updated with new assessments and quantifications.
  • Climate change and biosphere integrity identified as core planetary boundaries. Significantly altering either of these “core boundaries” would “drive the Earth System into a new state.”
  • Four boundaries are assessed to have been crossed, placing humanity in a danger zone: climate change, loss of biosphere integrity (biodiversity loss and species extinction), land-system change, altered biogeochemical cycles (fertiliser use — phosphorus and nitrogen).
  • Crossing boundaries raises the risks to current and future societies of destabilising the Earth System — the complex interactions of land, ocean, atmosphere, ice sheets, life and people.
  • Internationally agreed upper climate limit of 2 degrees lies beyond the climate change boundary: which makes 2 degrees a risky target for humanity, and therefore an absolute minimum target for the global climate negotiations.

Nine planetary boundaries

  1. Climate change
  2. Change in biosphere integrity (biodiversity loss and species extinction)
  3. Stratospheric ozone depletion
  4. Ocean acidification
  5. Biogeochemical flows (phosphorus and nitrogen cycles)
  6. Land-system change (for example deforestation)
  7. Freshwater use
  8. Atmospheric aerosol loading (microscopic particles in the atmosphere that affect climate and living organisms)
  9. Introduction of novel entities (e.g. organic pollutants, radioactive materials, nanomaterials, and micro-plastics).

Will Steffen, Katherine Richardson, Johan Rockström, Sarah E. Cornell, Ingo Fetzer, Elena M. Bennett, R. Biggs, Stephen R. Carpenter, Wim de Vries, Cynthia A. de Wit, Carl Folke, Dieter Gerten, Jens Heinke, Georgina M. Mace, Linn M. Persson, Veerabhadran Ramanathan, B. Reyers, and Sverker Sörlin. Planetary boundaries: Guiding human development on a changing planet. Science, 15 January 2015 DOI: 10.1126/science.1259855

 

 

Clmate change: A severe drought plagued a third of Queensland, Australia in 2013. Destabilizing the global environment could make Earth less hospitable for humans. (David Gray/Reuters)

 

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

By Joel Achenbach Washington Post January 16 2015

 

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 include 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….

 

…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 from these shocks. “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 to many of the environmental problems we face today. But technological innovations often come with unforeseen consequences. Pierrehumbert said we should be wary of becoming too dependent on technological fixes for global challenges. “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,” he said. “It becomes more and more like living on a spaceship than living on a planet.”

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