It's been an eventful ride, but the time is right for de Boer's departure

The well-deserved plaudits for the departing Yvo de Boer may still be flooding in, but that will not stop attention turning immediately to how the resignation of the UN's top climate change official will affect the ongoing negotiations and, more importantly, whether or not his replacement will have more luck in Mexico than de Boer enjoyed in Copenhagen.

If the haste seems a tad indecent, remember that the negotiations are too important for anyone to rest on their laurels – de Boer, perhaps more than anyone, understands that.

The first point is that despite the ultimately disappointing outcome of the Copenhagen summit, de Boer's replacement has quite an act to follow. For four years the Dutch diplomat has been a powerful driving force in the international negotiations, forcing climate change up the political, business and media agenda, frequently earning his sobriquet as the "conscience" of the increasingly fraught negotiations. The moment when he broke down in tears at the Bali summit in 2007 would have single-handedly ensured him a central place in the history of the fight against climate change, even before the subsequent years of cajoling, convincing and gentle bullying resulted in about half the world's leaders descending on Copenhagen.

He has earned the respect of his peers, effectively managed to balance the competing demands of politicians, businesses, NGOs and the media, and was instrumental in steering the Copenhagen summit back from the abyss and towards an agreement that, while flawed, at least holds out hope of a stronger deal being reached in Mexico in November.

And yet, de Boer is right, now is a good time for him to move on.

Regardless of the recent formation of a new advisory body to investigate climate financing options and the repeated pronouncements from politicians that the talks remain "on track", it is clear all the momentum built up ahead of the Copenhagen summit has dissipated.

The summit was an organisational morass, for which de Boer must take much of the blame, and there seems little doubt that the UN lost control of the crucial final few days of talks. Speaking off the record, senior government officials now admit Copenhagen was a "disaster" and that hopes for something better in Mexico are receding fast.

The Copenhagen Accord may look a little more appealing now all the world's top emitters have tabled emission plans, but there is still a huge amount to be ironed out and no new meetings have been scheduled beyond the Bonn conference in June and the Mexico summit in November.

Moreover, the mood surrounding the process is looking more ominous than ever. China and India have both gone on the record criticising the stance of the industrialised nations, the US administration is bogged down in partisan warfare over its climate change plans, and the vast majority of poorer countries still feel as if they are being sidelined.

There is an unmistakable sense of drift, and a new broom may be just what is needed to reinvigorate the talks in the build-up to Mexico.

If they can identify the right candidate with the requisite authority (preferably from the developing world to help mend some of the alienation felt by many poorer nations, although it might be worth noting Gordon Brown could be looking for a job soon and the one area in which has often impressed has been international diplomacy), then the UN can at least attempt to draw a line under the suspicion and back-biting that characterised the final few days in Copenhagen and try to restore momentum before Mexico.

Meanwhile, it is encouraging to see de Boer's assertion that it is businesses that will ultimately build the low-carbon economy he has been negotiating to deliver.

He will inevitably be criticised for cashing in his influence by taking up a role at KPMG, but his statement this morning reminded everyone why he was such an effective navigator of the seemingly interminable negotiations.

"I have always maintained that while governments provide the necessary policy framework, the real solutions must come from business," he said. "Copenhagen did not provide us with a clear agreement in legal terms, but the political commitment and sense of direction towards a low-emissions world are overwhelming. This calls for new partnerships with the business sector and I now have the chance to help make this happen."

Let's all hope he's successful.