​The annual Chatham House Climate Change Conference (#CHClimate) has become an established part of the calendar for climate-change wonks. This year's was the 17th conference. Its timing, on 21-22 October, just a few weeks before the annual UNFCCC COP, provides an opportunity for the climate-change community to brief each other, air new ideas, and rehearse their arguments for debates held during the two weeks of the COP. It's been some time since I attended a #CHClimate, which was probably before hashtags became popular, so attending this year was a great opportunity to find out how climate-change policy debate has moved on.

Of course, #CHClimate is almost all under Chatham House rules, especially the interesting bits, so I can report what was said but not who said it. In a way, that doesn't matter, as only three words capture the key message for me: risk, opportunity and psychology. And they're all about the framing of climate-change policy debate.

In the early years of #CHClimate, much of the debate was about whether climate change was happening and what level of emission reductions would be needed. The science now is clear, the more so with the recent IPCC report, and the policy aim is to keep global average temperature rise below 2°C. End of. Unfortunately, the need to act to keep global average temperatures below this threshold has escaped recognition by the wider public, while the urgency of action has escaped the policymakers. This is partly because it has been communicated in negative terms, namely: ‘in order to keep below the emissions ceiling, you must stop using fossil fuels’. The message now needs to be couched in terms of the risks of climate change to people and property. This makes it much more personal and tangible for the public, and much more relevant to the concerns of policy makers.

But the message also needs to be a positive one. Too much emphasis on the threat of risks and the damage climate change can do, could – at its worst – lead to crippling inaction from a sense that nothing can be done. So, the message also needs to be about opportunity – the opportunity to make life better for us and for future generations, and the opportunity for business to make a positive contribution and a return on investment.

And much of the success in mitigating both climate change and the risks of damage will be down to psychology. Changing attitudes, so that addressing climate change is not perceived as a constraint or a burden, and changing behaviours, so that people reduce their footprint on the environment, will both be necessary. This requires initiatives that recognise how people actually behave and think, instead of telling them how they should behave and think.

It was notable this year at #CHClimate that all eyes were not on Warsaw, where the next COP will be held, but on Paris, where the COP will be held in 2015. This is where the climate-change agreement will be concluded. The COPs in Warsaw (2013) and Lima (2014), and the climate-change summit called by UN Secretary-General Ban Ki-moon in September 2014, are not being seen as separate destinations but as milestones on the road to Paris.

However, few eyes at #CHClimate were on New York where, in 2015, the world’s leaders will gather, a couple of months before they meet at the Paris COP, to agree the post-2015 development agenda. The link between the two processes was mentioned two or three times, including during the last session where the question was specifically addressed, but almost reluctantly. It is hard to conceive of a post-2015 development agenda that does not incorporate the challenges of climate change; the parties to the UNFCCC are explicitly called on to promote sustainable development (Article 3). Yet these two processes – involving the same member states and both concluding in 2015 – are quite separate.

The different histories of the two processes and the different nature of the agreements (one legally binding, the other aspirational) suggest there are good reasons to keep them separate. But will reluctance to connect them in some way be a missed opportunity to further the objectives of one or other, or both of them? Like it or not, links are already being made: the idea of CBDR (common but differentiated responsibilities), for instance, has crossed over from UNFCCC to the post-2015 development agenda. The full implications of this are not yet known, but it is better surely to have an open and full debate about how the UNFCCC and the post-2015 development processes can support and reinforce each other, than have ambiguities about their relevance?

At the very least, the UN system, or member states, could be facilitating dialogue between those engaged in the two processes. This would help ensure that the ambition of sustainable development that is being formulated for the post-2015 development agenda can be reflected in the provisions of the climate-change agreement, and that effective approaches to address climate change can be reflected in the post-2015 development agenda.