But now, Ruth Defries, Erle Ellis and some of the authors of the Planetary Boundaries paper, including Diana Liverman, have published another paper, describing what they call “Planetary Opportunities”. “Scientists’ most useful role is not to set doomsday limits and set thresholds, but to provide a more optimistic opportunity for society,” Ellis told me. “There is no hard-line carrying capacity for the planet. Humans are very adaptive.”
Urbanisation is a good example of the human system responding to a planetary opportunity, Ellis says. By living more efficiently in larger populations, we free up rural land for ecosystem services or agriculture. We need to apply human ingenuity on a multi-scale approach – from individuals to global, both in governance and in the scale of scientific analyses – in order to find solutions, he says. Societies have successfully adapted to environmental threats in the past. “Planetary boundaries are not a useful concept for society,” Ellis says.
Another article published this week goes even further, claiming the Planetary Boundaries concept is "scientifically flawed", and shouldn't be used to guide global environmental policy. Ted Nordhaus and Michael Shellenberger of the Breakthrough Institute environmental think tank say that many of the Anthropocene conditions we've brought about have been to the net benefit of humanity.
Rockstrom counters, saying: “We should not frame this crisis as an opportunity. This is not an opportunity. If we destroy the water supply, the air, the climate, humanity will not be safe,” he says, adding that he finds the whole ‘technology-will-solve-all-our-problems’ camp tiresome. “But, the journey towards something good represents an opportunity. The safe operating space is an opportunity,” he concedes.
Rockstrom worries that reaching tipping points could send us into another state that we have no previous experience of, and which is likely to be dangerous. Exceeding the planetary boundaries, he warns, is a very dangerous game, adding that we already have for three of the nine (climate change, nitrogen cycle and biodiversity loss).
Perhaps the truth is that for most of our species' history, we've effectively lived among limitless resources. There are many examples of societies exceeding environmental limitations with disastrous consequences, as well as some encouraging ones of good environmental stewardship. But perhaps we have not got any better at recognising thresholds except with hindsight. Apart from gravity and (effectively) sunlight, everything else we use has its limits. Whether we can identify those ones crucial to our survival – and whether our poorly adapted human brains are unable to act on this message – is another question.
A timely reminder of this is the forthcoming Earth summit in Rio de Janeiro. It’s commonly known as Rio+20 because 20 years have passed since the original summit in the same city. That produced a raft of environmental management treaties and declarations – including the United Nations Framework Convention on Climate Change (UNFCCC), the basis for governments’ attempts to curb global warming gases.
But progress on addressing the most critical global challenges, such as climate change, has reached a farcical level in which time spent arguing over punctuation and grammar in lengthy documents has stymied any real action on greenhouse gas emissions. And in the meantime almost all environmental problems targeted by the original summit have got worse rather than improved.
The optimist in me hopes the promise and language of opportunities may spur action at Rio, respecting the biophysical limitations of our finite planet.