Rio+20 and Its Shades of Grey
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In September, a diverse group of scientists—among them the Nobel laureate Paul Crutzen—presented in the journal Nature a new framework to analyze sustainable development at a global scale. This framework recognizes that humans have now become the main driver of global environmental change, and that our impact on the planet is growing stronger.
We are affecting every one of the major natural processes which are important for our own welfare, wrecking the ability of earth systems to regulate themselves, and buffer disturbances. In fact, our actions may be shifting earth processes to a completely new state that is a far cry from the extraordinarily stable conditions (in the entire history of planet earth) that allowed the development of human civilization since 10,000 BC. In the words of Paul Crutzen and colleagues, we have entered a new geologic era, the “Anthropocene”.
Our pressure on the planet appears more and more troubling as our understanding of earth processes improves. There is increasing evidence that many earth systems and biophysical phenomena do not change in a linear fashion, but rather experience abrupt changes when thresholds are crossed.