No-one can really blame him. Yvo de Boer, the born optimist, eternal diplomat, the mediator, has thrown in the towel and announced his resignation as head of the UNFCCC, the Bonn-based climate secretariat.

He is too much a loyal servant to the UN, perhaps too committed to the cause to which he has devoted so much effort, to say it directly. But there can be no doubt that the disastrous failure of the Copenhagen climate conference was the last straw for Yvo de Boer.

Responsibility for Copenhagen

Before the Copenhagen conference, the UN climate chief pushed hard for a substantial agreement and did not mince his words in stressing the disastrous effects of climate change the world would face without international action.

How disappointing for him then, after four years in the "hot seat" at the UNFCCC, to be forced onto the sidelines in the final stages of that meeting, while the USA and China played their own games and fought out their power battles. How demoralizing to see that minimal consensus in the "Copenhagen Accord," a toothless declaration, not recognized by everyone, and with no legally binding status for anybody.

Of course de Boer himself cannot be exonerated from responsibility for the chaotic proceedings and meagre results of the Copenhagen meeting. The UN Secretariat and the Danish host government must share responsibility for the preparation, execution and ultimate failure of the conference.

Nevertheless, the man who earned himself a reputation as a fair and untiring negotiator and committed fighter for the world's climate deserved a better outcome.

No surprise

It is hardly surprising that Yvo de Boer is giving up. It is rather a wonder that he withstood the pressure of his mammoth task for so long.

When the Bali conference was in danger of failing two years ago, de Boer left the room in tears. Plenty of people thought that would be the end of his career at the UNFCCC. But the conference brought results after all, and de Boer stayed on and came to represent the "human face" of climate change.

His departure comes at a time when the climate negotiations are at a key turning-point. The economic crisis, the domestic political constraints crippling US President Obama in international negotiations, China's growing power and its rejection of outside control – all these factors make it highly unlikely that the next major climate conference in Mexico at the end of this year will bring true progress towards a binding agreement to succeed the Kyoto Protocol, which runs out in 2012.

In spite of his disappointment over the Copenhagen fiasco, the UN climate chief still tried to defend the result. After all, that was his job. The fact that an increasing number of critics are doubting whether the UN is the forum for the world's climate negotiations must have hit him hard.

Now, he's drawn his own conclusion and is switching to private enterprise, in the hope of finding sustainable climate solutions on that level. Someone else will have to take on the thankless task of negotiating the political framework.

Commentary: Irene Quaile
Editor: Nathan Witkop