Nature Studies: Is this the year the world finally agrees on a plan to halve climate change?

If you’re under 60 you’ve probably never heard of Le Bourget.

Years ago, it was the main Paris airport, then it was replaced by Orly, which in turn was replaced by Charles de Gaulle. Now it’s an airfield in northern Paris mainly used by business jets. But you’ll be hearing plenty about it at the end of this year, because the Le Bourget conference centre, the Paris-Le Bourget Parc des Expositions, is the scheduled site for the meeting to save the planet.

If that seems a bit dramatic, it’s no more than the truth. In early December, 196 countries will come together there to have one last go at agreeing “a binding and universal agreement on climate change, from all the nations of the world”. The key players will be President Barack Obama of the United States and President Xi Jinping of China, with a make-or-break role very possibly afforded to the Indian Prime Minister, Narendra Modi, although it seems likely there will be many other heads of state and government present, including Britain’s leader, be it David Cameron, Ed Miliband, or someone else – for this will be an assembly like no other.

In fact, the enormity of what is at stake at COP21, or the 21st conference of the parties of the United Nations Framework Convention on Climate Change, is just starting to become clear. Can the whole world really agree in Paris to limit, in a legally binding way, the emissions of greenhouse gases which, all governments now accept, are changing the atmosphere with potentially disastrous consequences for humankind? That’s the aim. Or will the process fall apart, as it did six years ago at the UN climate conference in Copenhagen, the last time a formal agreement was attempted?

Barring major wars, this will be the principal geopolitical event of 2015; and there are good omens for it, and bad omens. Perhaps the worst has been the outcome of the most recent UN climate conference, COP20, held in December at Lima in Peru, which was meant to clear the way for Paris, but which merely showed that the issue which wrecked the Copenhagen conference in 2009, and bedevils the negotiating process, is still very much alive – the divide between developed and developing countries about who should do what.

The developing nations want the main burden of emissions reductions to fall on the rich countries, but the US, for one, will no longer accept this idea, not least as a “developing” country such as China has now in effect become a developed country (and far surpasses America in its CO2 emissions), with other developing countries such as Brazil and South Africa heading the same way. Add the fact that the negotiating process itself is impossibly tortuous – imagine securing accord from nearly 200 nations, all with their own agendas, and their delegations grandstanding to audiences back home – and the prospects for a Paris treaty look bleak.

But there are good omens too. The best is the remarkable bilateral climate agreement last November between the US and China, in which both nations agreed to cut their carbon emissions to a greater degree than ever before, and to work on the global warming issue jointly. This matters for two reasons, the first being that they are the biggest emitters, with 45 per cent of the global total between them (China, 29 per cent, and the US, 16 per cent). The second is that, in the past, they have been the biggest obstructers of agreement: the US after President George W Bush in 2001 withdrew America from the previous emissions treaty, the Kyoto Protocol, and China has been afraid that climate-based restriction would damage its soaraway economic growth.

But the Chinese now accept that climate change is a major threat to them, and are willing to act; and Obama is not George W Bush. It is clear that the current American president increasingly sees climate as an issue that may determine his legacy; a successful Paris treaty would be the sort of enduring and memorable success for him that Bill Clinton sought – and failed to get – in the Camp David Summit between Israel and the Palestinians in 2000.

The commitment of President Obama, and of President Xi, may give the Paris treaty a chance; what may yet derail it is the reluctance of India, now the world’s third biggest carbon emitter (with 7 per cent of the total), to see restrictions to its economy, and in particular its mushrooming use of coal in its power stations. Prime Minister Modi may wreck the treaty; Obama has just been to visit him, and they talked climate, and CO2 emissions, politely.

The stakes are enormous. There is nothing more fascinating this year than watching the approach to Le Bourget.

Twitter: @mjpmccarthy