January 22, 2015, by James Dyke

The Earth’s climate has always changed. All species eventually become extinct. But a new study has brought into sharp relief the fact that humans have, in the context of geological timescales, produced near instantaneous planetary-scale disruption. We are sowing the seeds of havoc on the Earth, it suggests, and the time is fast approaching when we will reap this harvest.

This in the year that the UN climate change circus will pitch its tents in Paris. December’s Conference of the Parties will be the first time individual nations submit their proposals for their carbon emission reduction targets. Sparks are sure to fly.

The research, published in the journal Science, should focus the minds of delegates and their nations as it lays out in authoritative fashion how far we are driving the climate and other vital Earth systems beyond any safe operating space. The paper, headed by Will Steffen of the Australian National University and Stockholm Resilience Centre, concludes that our industrialised civilisation is driving a number of key planetary processes into areas of high risk.

It argues climate change along with “biodiversity integrity” should be recognised as core elements of the Earth system. These are two of nine planetary boundaries that we must remain within if we are to avoid undermining the biophysical systems our species depends upon.

The original planetary boundaries were conceived in 2009 by a team lead by Johan Rockstrom, also of the Stockholm Resilience Centre. Together with his co-authors, Rockstrom produced a list of nine human-driven changes to the Earth’s system: climate change, ocean acidification, stratospheric ozone depletion, alteration of nitrogen and phosphorus cycling, freshwater consumption, land use change, biodiversity loss, aerosol and chemical pollution. Each of these nine, if driven hard enough, could alter the planet to the point where it becomes a much less hospitable place on which to live.

The past 11,000 years have seen a remarkably stable climate. The name given to this most recent geological epoch is the Holocene. It is perhaps no coincidence that human civilisation emerged during this period of stability. What is certain is that our civilisation is in very important ways dependent on the Earth system remaining within or at least approximately near Holocene conditions.

This is why Rockstrom and co looked at human impacts in these nine different areas. They wanted to consider the risk of humans bringing about the end of the Holocene. Some would argue that we have already entered a new geological epoch – the Anthropocene – which recognises that Homo sapiens have become a planet-altering species. But the planetary boundaries concepts doesn’t just attempt to quantify human impacts. It seeks to understand how they may affect human welfare now, and in the future….

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