Safe Operating Limits for Spaceship Earth

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As an experienced aviator, Australian entrepreneur Dick Smith – who recently announced the Wilberforce Award – understands well the need to define ‘safe operating limits’ as it relates to flight.

The defence forces also understand this concept, with no mission allowed to embark before the ‘safe operating limits’ have been established.

Johan Rockstrom, Executive Director of the Stockholm Environment Institute and the Stockholm Resilience Centre, gave a TED talk in July 2010 about nine critical planetary boundaries that can help us to protect ourselves from breaching the ‘safe operating limits’ of the planet’s many overlapping ecosystems:

These boundaries (summarised from Stockholm Resilience Centre) are:

graphic showing the nine planetary boundaries and whether they are within, or exceed, the limit for safe operating
The Nine Planetary Boundaries (click to enlarge) | image from the New Scientist

Stratospheric ozone layer – a thinning ozone layer means greater amounts of ultraviolet (UV) radiation reaching ground level, which contributes to a higher incidence of skin cancer in humans and can damage terrestrial and marine life.

Biodiversity – the 2005 Millennium Ecosystem Assessment reported that changes in biodiversity due to human activities were more rapid in the past 50 years than at any time in human history.

Chemicals dispersion – the cumulative effect of emitting toxic compounds such as metals and persistent organic pollutants, which bioaccumulate up food chains,  include reduced fertility and the potential for permanent genetic damage.

Climate change – evidence suggests that this planetary boundary has already been transgressed, but the question is how long can we breach this limit before significant, irreversible change occurs.

Ocean acidification – about 25% of the CO2 humanity produces is dissolved in the oceans, forming carbonic acid, altering ocean chemistry and decreasing the pH of the surface water. This can significantly impact on the formation of marine life such as coral, shellfish and plankton, and undermine the basis of marine food chains.

Freshwater consumption and the global hydrological cycle – the availability of freshwater is strongly affected by climate change, and also human pressure, which is now the driving force determining how and where freshwater is used; it is estimated that by 2050 about half a billion people could be classed as ‘water-stressed’.

Land system change – a major contributor to the loss of biodiversity is the conversion of forests, wetlands and other wild areas to agricultural land.

Nitrogen and phosphorus inputs to the biosphere and oceans – more nitrogen is converted from the atmosphere into reactive forms by human activity than all of the rest of the Earth’s terrestrial processes combined; reactive nitrogen pollutes land, air and water.

Atmospheric aerosol loading – because of their influence on the climate system and their adverse effects on human health at a regional and global scale.

Its important science, but in terms of communicating what it means, it seems remote, its big in scale, and its hard to make the connection – I can just hear a number of people saying: ‘Whew! That’s a lot of scientific-y stuff! But what do nitrogen levels and biodiversity and land use change have to do with me, or my work?’

For audiences where concern for ecosystems and biodiversity may not resonate, expressing limits in terms of risk and safety – a ‘safe operating limit’ – could be a powerful way to help communicate the importance of limits.

What other ‘languages of limits’ do we need?

Published by Sharon Ede

Sharon is an ideas transmitter, writer and activist who writes, collects, and shares stories on communication and change for sustainability at cruxcatalyst and is founder of Share Adelaide Share Adelaide. Sharon has been working on sustainability issues in paid and voluntary work since 1993 and loves playing connect the dots by cultivating a wide network of people working on sustainability.

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