How can the world community achieve a shared, new, understanding of the complex, interactive and non-linear nature of the Earth System, against the prevailing, misleading and policy-impeding assumption of a mechanistic ‘Newtonian’ world, amenable to reductionist technical fixes applied in incremental fashion?

Modern societies, and their governments, typically view the natural world in essentially mechanistic fashion — imagining that piecemeal technical solutions can be found for specific aspects of environmental disruption or depletion. Systems thinking and analysis, including an understanding of ecological processes, has not been part of our schooling, culture and world-view. We are thus failing to grasp the potential seriousness of exponential change functions, synergistic stressors, natural limits, critical thresholds and surprises.

Obstacles to achieving such change include the familiar difficulties in ‘re-educating’ existing adult generations, failure of imagination, resistance from those with vested interests in prevailing views/models (including conservative religious and schooling authorities), and the difficulties and diffidences that afflict scientists in their potential public role as communicators and educators. Governments’ (electoral) preoccupation with balancing the budget rather than the biosphere is a natural consequence of the above — and therefore a further major impediment.

In hierarchical terms, what human-driven forces can potentially trigger abrupt transitions and non-linear response in biosphere? What critical thresholds and feed-mechanisms are involved and how do they operate?

We need to improve our understanding about still unknown functional mechanisms operating at the global Earth system scale that can be involved in unpredictable catastrophic events. Such knowledge is necessary to predict, prevent, adapt to and eventually manage unexpected consequences of human action on global change.

What will be the true magnitude of cumulative effects of global change?

To date many global change questions have focused on a component (e.g. the C cycle or sea level rise). The true outcomes of global change will be dictated by cumulative impacts, interactions and feedbacks. If they’re not addressed we may get some nasty non-linear surprises.