Though it is but a brief statement of principles and commitments produced by a small cluster of states, the much-derided Copenhagen accord may turn out to be the most hopeful way for the world to actually start to counter climate change.

It is not a route that will necessarily command general approval; the UN is somewhat sidelined. Yet because it recognises core geopolitical realities and works with, rather than against them, it carries promise. The countries behind the accord – the US, China, India, Brazil and South Africa – include the three biggest carbon emitters in the developing world, plus the most polluting industrialised state.

We have to innovate in international relations if we are to hold the global average temperature increase to 2°C. The accord represents a beginning that can be built upon – in principle far more rapidly than would have been possible with the cumbersome scenario envisaged pre-Copenhagen. If the agreement can be quickly given a robust form, it could help break the existing logjam, where each nation or group of nations is waiting for others to lead.

But what kind of framework might emerge in the short- and medium-term? Will smaller and poorer countries suffer as larger ones progress on their own? Not necessarily, at least if the overall architecture is right, and they organise to represent their specific concerns. The experience of the World Trade Organisation is instructive: failure to conclude a universal set of trading agreements has spawned a variety of new measures and organisations. The very diversity of groups and regions involved has proved as much a source of strength as of weakness. The same could be true in the case of climate change.

While the accord could provide an anchor, we will also need a diversity of bilateral and regional agreements and – yes – “coalitions of the willing”. The US and China must continue to negotiate bilaterally in a serious and committed way, whatever more general agreements they commit to. The EU should be involved in discussions too, though it must learn to speak with one voice if it is to avoid being sidelined again. And the many developing countries that are among the 20 largest polluters also must meet regularly with these industrialised states.

There are obvious dangers in an approach that does not focus on bringing all nations on board. Yet at this point there is no alternative.