Have we fatally damaged Earth's life support systems?


Since 1950, nitrogen entering the oceans as run-off from agriculture has quadrupled.
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Forget climate change, have we already so degraded land and freshwater systems that we have put the viability of life on Earth at risk? Two new studies suggest that, if not past the point of no return, we need to rethink how we use our resources urgently.

As The Guardian reports

Of nine worldwide processes that underpin life on Earth, four have exceeded “safe” levels – human-driven climate change, loss of biosphere integrity, land system change and the high level of phosphorus and nitrogen flowing into the oceans due to fertiliser use.

Two new major Australian-led studies – one published in Science, the other in The Anthropocene Review – found that the changes of the last 60 years are unprecedented in the previous 10,000 years,

The researchers spent five years identifying core components that make our planet suitable for human life. They used the long-term average state of each measure to provide a baseline for the analysis.

The scientists, led by Prof Will Steffen of the Australian National University and the Stockholm Resilience Centre, found that since 1950 there has been a 700% increase in urban populations, a 500% increase in energy and eight times the amount of fertiliser poured on to farmland. That has increased nitrogen entering the oceans by 400%, causing potentially catastrophic shifts in the state of the planet.

Researchers say that the direct impact on the land, such as this clearing of the Amazon forests to graze cattle, is more concerning even than climate change.
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“These indicators have shot up since 1950 and there are no signs they are slowing down,” Steffen says. “When economic systems went into overdrive, there was a massive increase in resource use and pollution. It used to be confined to local and regional areas but we’re now seeing this occurring on a global scale. These changes are down to human activity, not natural variability.”

Steffen says direct human influence on the land is contributing to a loss in pollination and a disruption in the provision of nutrients and fresh water.

We are clearing land, we are degrading land, we introduce feral animals and take the top predators out, we change the marine ecosystem by overfishing – it’s a death by a thousand cuts. That direct impact upon the land is the most important factor right now, even more than climate change.

The researchers say that there is no guarantee – or even evidence – that animals, including humans, will be able to evolve fast enough to deal with rapidly rising temperatures. Steffen's conclusions are gloomy to say the least.

It’s clear the economic system is driving us towards an unsustainable future and people of my daughter’s generation will find it increasingly hard to survive. History has shown that civilisations have risen, stuck to their core values and then collapsed because they didn’t change. That’s where we are today.

Steffen held a news briefing in Adelaide this morning to discuss the papers' findings. The Australian Science Media Centre will post full audio of that briefing shortly. We'll post a link as soon as its available.

  1. http://www.sciencemag.org/content/early/2015/01/14/science.1259855
  2. http://anr.sagepub.com
  3. http://www.smc.org.au/2015/01/briefing-alert-have-we-f%ED-the-planet-yet-science-anthropocene-review/#more-15892
  4. http://www.smc.org.au/2015/01/briefing-alert-have-we-f%ED-the-planet-yet-science-anthropocene-review/#more-15892
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