Snow fell as temperatures plummeted outside the conference halls
There were 45,000 people at the Copenhagen summit and more than 100 world leaders, but in the end it came down to an extraordinary personal showdown between the leaders of the world's two superpowers and biggest greenhouse gas emitting countries, China and the US.

The deal itself was anything but historic. But the implications of how the Chinese handled this negotiation well might be.

In a disastrous result for the world's environment and for 19 years of difficult and painstaking environmental diplomacy, China undoubtedly won.

Chinese chief negotiator Xie Zhenhua said China was leaving Copenhagen "happy", before walking out of the Bella conference centre late on Friday night with his clearly cheerful team .

In a statement, Xie, who is also vice-chairman with China's National Development and Reform Commission, said Chinese Premier Wen Jiabao was also happy with the agreement.

They are about the only people in the world who are happy about Copenhagen's failure, except perhaps those who are sceptical about the science of global warming and who therefore think global emission reduction efforts are not necessary in the first place.

US President Barack Obama left the Danish capital having been forced to muscle through a very weak political deal that achieved few of his key aims and wasn't binding anyway, in order to salvage the barest bones of a deal.

In a private press briefing for American journalists where he unilaterally announced the deal before heading home, he was blunt that it fell a long way short of what science says needs to be done and a long way short of expectations.

After arriving in Copenhagen late on Thursday, Obama went to a meeting of 25 key leaders - including Prime Minister Kevin Rudd - early on Friday morning to try to salvage an agreement.

The fact that the leaders were getting down to the word-by-word text negotiations usually conducted by officials showed just how desperate things had become. They had met the night before until 2am after the "gala" opening dinner with the Danish royal family and got nowhere. According to Rudd they were looking into the "abyss" of total failure.

Part of the problem was the complete refusal of the Chinese to engage in the talks.

The conference had been bogged down for almost two weeks by procedural blocking tactics by developing countries and China, which senior negotiators believe were almost entirely engineered by the Chinese.

Despite the fact that the "texts" that negotiators had worked on for more than two years were hopelessly far from agreed, China and the G77 block of developing nations resisted all attempts to bring politicians into the talks.

They skilfully exploited heavy-handed tactics by the Danish presidency to achieve a political agreement by describing it as a plot to "kill" the Kyoto Protocol, and were strongly supported by many of the environmental and aid activists at the conference, who in turn provided sound grabs to the assembled world media.

Initially these tactics were seen by negotiators as a strategy by China to force through a more favourable deal in the final days as negotiators grew more and more tired and desperate for a deal and more intent upon getting home for Christmas.

But when Chinese Premier Wen Jiabao, who was already in Copenhagen, refused to attend the Friday morning talks and was represented by China's third-ranking official instead, negotiators realised they were dealing with something far more serious.

It was a snub to the US President that deeply angered US and European negotiators because it subverted the purpose of the meeting to crunch a leaders-level deal.

Making progress even harder was the insistence by the G77 group of developing nations that its hardline negotiators, including Sudanese ambassador Lumumba Di-Aping who has now twice likened developed countries' attitudes towards climate change to Nazism, should be in the room.

Accounts suggest Di-Aping and US Secretary of State Hillary Clinton did not always see eye to eye. The real question is why they were even sitting at the same table.

When the meeting finally broke for the formal leaders' statements mid-morning things got even worse. In his speech, Obama repeated the demand that developing nations' emission reduction promises had to be verifiable, a demand China was fiercely resisting in the grounds that it was an assault on its sovereignty.

"Without any accountability, any agreement would be empty words on a page," Obama said, reportedly offending the Chinese Premier so much that he returned to his hotel.

And Wen did not show again for another leaders-level meeting after the speeches, sending an even lower level official.

When the President and the Premier finally met bilaterally there was an altercation between officials over access for each state's media.

Finally, late in the day Obama and Clinton met the leaders of China, India, Brazil and South Africa and clinched the "Copenhagen Accord". According to some reports, quoting unnamed US officials, that meeting only came about because the Americans barged in on a gathering of the developing nation leaders and insisted on taking part.

In any event, having refused to engage in political-level discussions for two weeks on the grounds that everything had to be done by consensus and with the democratic inclusion of all 192 parties to the talks, at the eleventh hour the Chinese did do a deal with just a handful of the most powerful nations in the world.

And that deal protected its own interests, setting back international efforts to put Chinese and Indian emission reduction targets into an international legally binding treaty and weakening demands for international verification.

But it did not protect the interests of the developing countries who had been supporting the Chinese blocking tactics all through the conference, because it did not achieve deeper emission cuts from the main emitters that came anywhere close to what will be needed to contain rising world temperatures.

In fact it achieved a deal far weaker than the worst-case scenarios that might have been imagined when delegates arrived two weeks before.

Even the crucial timetable to achieve a legally binding treaty by 2010 was taken out at the insistence of the Chinese, who said they would otherwise reject the pact.

The powerful G77 block had already fractured during these talks, with developed nations including Australia putting in a lot of effort to convince countries that their best interests did not lie in continuing to be allied with China.

As they left, Copenhagen negotiators were wondering whether, having been abandoned so dramatically, China's allies will trust the superpower again. It appeared the fracturing of the G77 may have become a permanent fissure.

They were also questioning why China had taken the attitude that it did.

No one was asking China to do anything more than the energy-intensity based emission reduction targets that it had voluntarily announced a few weeks before the negotiations began.

And while there are political and cultural reasons for China to have particular sensitivities about questions of sovereignty, they have not prevented China from participating in verification regimes in other kinds of international agreements.

Nor was it apparently a tactic to secure greater concessions from the US, such as an improvement in its emissions reduction target of 17 per cent by 2020 based on 2005 levels, because these talks never got down to the details.

The endless debate about process, the endless argument about whether or not to talk about a deal, the endless rhetoric about the historical responsibility of the West, the rants about the evils of the capitalist system, meant there was no real top-level negotiation about what emission targets each country would take on.

This negotiation never really got to discover each nation's bottom line. Business representatives wandered somewhat aimlessly around the conference centre because there wasn't really a debate in which they could become engaged.

In the end, it probably came down to the fact that China won either way. If a deal collapsed, then they were off the hook of ever having to commit to legally binding targets, If the tactics succeeded in watering down a deal, then a legally binding target could still be shoved off for years.

There are good arguments for developed nations to take on tougher targets than the minimums they have on the table as part of a comprehensive global deal. But there are also very good reasons for them to demand that the world's largest emitter and other big developing-world emitters, such as India, be gradually drawn into the binding international mitigation system.

Unless the superpowers can find a way to bridge their differences, unless multilateral negotiations can find a way to get past the intractable north-south divide on this issue, solutions will continue to be elusive.

And that will have consequences for everyone. There are no real winners from the failure at Copenhagen.

Of course, among the protesters the US got the blame. As exhausted delegates finally left the Bella Centre they were confronted with a small band of demonstrators bearing posters of Obama with the slogan "climate shame" across his forehead.

But according to the negotiators who ploughed through these past two weeks of bitter negotiations in the bitterly cold Danish winter, China should also take a large share of the opprobrium. Climate is shaping as an issue that will test how China deals with the international responsibilities that sit alongside its emerging superpower status. In Copenhagen it failed that test.