What do we want global environmental governance to achieve? “Sustainable development” might seem like an obvious target for the coming discussions at Rio+20. But this would be a much too simplistic answer. At least if we are interested in taking the dramatic institutional implications of recent insights from Earth system science seriously.
One recent Earth system science synthesis seems to have caught considerable attention from the international community: the notion that there is a “safe operating space” within which the global human community can act, without seriously challenging the continuation of the current planetary state. These so called “planetary boundaries” defined by Johan Rockström and colleagues  remain debated within the wider Earth system science community. But it would be a huge mistake to discard them as irrelevant for policy. On the contrary, the framework captures a fundamental insight from the Earth system science community: that global environmental change unfolds in complex ways between multiple bio-geophysical systems. And that Earth system changes can be rapid, negative and practically irreversible.
Hence any discussion on how to reform global environmental governance, should not only focus on how to reach static global targets - such as the target to limit the global temperature rise to 2 °C above the average temperature before the industrial revolution. It should also focus on our ability to deal with complex, non-linear and interacting bio-geophysical thresholds at the planetary scale.
This might sound like an attempt to heap buzzwords on top of each other. It isn’t. On the contrary, this insight has several tangible implications for what we need global environmental institutions to achieve in the next few decades. I see at least three emerging topics for researchers of institutions and global environmental change.
The first issue is related to our global capacity to deal with global surprise – that is situations in which the behaviour in a system, or across systems, differs qualitatively from expectations. While some of the impacts of global environmental change can be predicted or at least estimated through modeling and scenarios, other events will unfold as surprise events. Recent examples here include the 2008 “food crises”; outbreaks of novel infectious human, animal or plant diseases; or extreme weather events that trigger social turbulence and political instability.
Many of these surprise events will unfold within the coping capacity of institutions. Others can propagate, and create severe threats to human well-being. The problem is of course that we know little of the phenomena - social, economical or ecological - that act as amplifiers. We do know however that institutional capacities tend to be severely outstripped when amplifying feedbacks in social-ecological systems do not match previous experiences; embed scientifically and socially contested cause and effect relations; and when information integration are challenged by organizational silos, and geographical and temporal gaps in ecological monitoring. So the first question is: how do we build stronger international capacities to detect and respond to surprising global events of great importance to human well-being? 
The second is not related to crisis events, but rather underlying drivers of global change . The fact that several Earth system processes (say climate change, biodiversity and land-use change) interact in ways not fully understood by science, poses difficult challenges. Not only because scientific uncertainty is often used as an excuse for political inaction, but also because Earth system interactions are affected by an opaque set of international institutions rather than by a set of simply-defined international institutions. Hence, we cannot take for granted that international institutions will emerge to deal with planetary boundaries and their interactions, despite their possible critical impacts on human well-being. In essence: which tangible complements to international institutions are able to address complex Earth system interactions? Should we instead put our faith on the emergence of global partnerships and networks, polycentric systems, or alternative multilevel governance initiatives? 
The third issue relates to the role of innovation and emerging technologies in building global resilience. Calls to support technological innovation as a strategy to achieve sustainability are increasingly common in the debate. The question is what the role of international actors - such as the UN system and public-private partnerships - should be in this discussion. Despite an increasing interest in green innovation by international actors, current focus tends to have bias towards technical systems, rather than on innovations that address social-ecological feedbacks, and support the stewardship of ecosystem services. In short: shifting the discussion about innovation from technology to ecology is a critical yet poorly explored issue as we enter the Anthropocene. 
But innovations have another dimension. A suite of emerging technologies such as synthetic biology, nanotechnology and geo-engineering pose difficult and unprecedented challenges to Earth system governance. The reason is their novelty, and possible yet hard-to-estimate risks. These technologies highlight the need for not only supporting local innovation - such as community-based climate adaptation projects - but also for establishing overarching governance principles that facilitate scientific and societal debate about high-risk technologies in institutionally fragmented settings. 
What is it really that we want global environmental institutions to do? I believe that we need to elaborate at least three issues: our global capacity to cope, recover and learn from global surprises; our ability to address complex Earth system interactions; and our need to support, as well as to regulate innovations that have great implications for the resilience of ecosystems. Only then will we be able to govern a complex and changing Earth system.
 Rockström J., W. Steffen, K. Noone, Å. Persson et al. (2009) A safe operating space for humanity. Nature 461: 472-475.
 Galaz, V., F. Moberg, E-K Olsson, E. Paglia and C. Parker (2010). "Institutional and Political Leadership Dimensions of Cascading Ecological Crises", Public Administration, 89 (2): 361-380.
 Walker, B., S Barrett, S. Polasky, V. Galaz et al. (2009). “Looming Global-Scale Failures and Missing Institutions”, Science 325:1345-1346.
 Galaz, V., F. Biermann, C. Folke et al. (in review). Planetary Boundaries – Exploring the Challenges for Earth System Governance.
 Olsson, P. and V. Galaz (in press). “Social-ecological innovation and transformation”, in Social Innovation: Blurring Sector Boundaries and Challenging Institutional Arrangements. A. Nicholls and A. Murdoch (eds). Palgrave MacMillan.