While the IPCC’s 5th Assessment Report demonstrates an increased confidence among the world’s climate scientists of the causal relationship between anthropogenic (man made) greenhouse gas emissions and a dangerously warming planet, paradoxically, it will not necessarily be the science that drives the negotiation processes at the 21st Conference of the Parties to the UN Framework Convention on Climate Change to be held in Paris, later this year.

Much of the burden of necessary economic and societal change to meet the IPCC’s warming target of no more than 2 degrees celsius average global temperature rise above pre-industrial levels, will fall on the energy sectors of the world’s industrialised and industrialising economies. But country negotiators, charged with protecting their national economic interests as well as acting responsibly in the face of the climate threat, have complex trade-offs to consider. Not the least of these is the notorious prisoner’s dilemma paradox, which requires that no single negotiating party (and over 190 countries will take part in the Paris negotiations), can play for the most advantageous outcome from its individual perspective without imperilling the collective, in this case the planetary outcome.

But this is only the beginning of the complexities inherent to the negotiation process. With respect to energy systems, each country will seek to resolve a difficult balancing act between achieving energy security, (so that the lights don’t go out) affordable energy (so that the economic burden of transition to a low carbon system doesn’t cripple the rest of the economy) and a rate of system change (decarbonisation) that meaningfully addresses climatic imperatives.

To date, countries have negotiated to achieve a reasonable balance within the “energy trilemma” by simply delaying making binding commitments to deep decarbonisation of their energy systems. But further delay is no longer an option if the 2 degrees target is to be taken seriously. On this matter, the 5th Assessment Report is very clear.

The word is out that country negotiators expect that a binding agreement will emerge from the Paris Conference. But what kind of an agreement will it be? A second, and perhaps more ominous trilemma overshadows the negotiation process. This is the trade off between pragmatism (what rate of system change is actually feasible given the lock-in and path dependence of complex energy systems embedded within complex industrial economies) time sensitivity (to what extent can an affordable rate of change be ordered and delivered so that in a time sense, the process of change is front loaded – more delay pushes up costs and infringes on feasibility) and finally the rigidity of the target. How robust is the commitment to 2 degrees?

Because it is the accumulation of greenhouse gas emissions that drive global warming and thereby, climate change, the global warming target determines the available carbon budget that can be spent before the greenhouse gas ceiling is reached. At current emission rates and a 2 degrees warming target, we blow the budget some time around 2025.

In climate negotiation, complexity is piled upon complexity, and with each complexity, unknowns are piled upon unknowns so that calling the outcome of the negotiating process is a fools errand. What will give? Whose interests will most dominate the outcome? Past performance suggests that those with the least standing, those whose voice is the most quiet (or the most effectively silenced) will lose out. But there again, complexity may have the upper hand. With so many complex systems teetering on the brink, one thing can be assured, the past will be a very poor guide to what the future holds in store.

This blog is inspired by a recent Grantham Institute seminar on the IPCC 2014 Synthesis Report held at Imperial College London under Chatham House Rules.

Nick Gallie is a doctoral researcher at SPRU. His research is focused on climate change discourse. Nick holds Masters Degrees in Political Economy, Human Rights and Science and Technology Policy Studies