Top U.N. climate change official Yvo de Boer told The Associated Press on Thursday that he was resigning after nearly four years, a period when governments struggled without success to agree on a new global warming deal.
His departure takes effect July 1, five months before 193 nations are due to reconvene in Mexico for another attempt to reach a binding worldwide accord on controlling greenhouse gases. De Boer's resignation adds to the uncertainty that a full treaty can be finalized there.
De Boer is known to be deeply disappointed with the outcome of the last summit in Copenhagen, which drew 120 world leaders but failed to reach more than a vague promise by several countries to limit carbon emissions -- and even that deal fell short of consensus.
But he denied to the AP that his decision to quit was a result of frustration with Copenhagen.
"Copenhagen wasn't what I had hoped it would be," he acknowledged, but the summit nonetheless prompted governments to submit plans and targets for reigning in the emissions primarily blamed for global warming. "I think that's a pretty solid foundation for the global response that many are looking for," he said.
De Boer told the AP he believes talks "are on track."
He recommended the next talks take a different tack. Rather than convene several negotiating sessions involving nearly 200 countries, Mexico, which is chairing the negotiations throughout this year, should prepare the November conference to work in smaller groups to lay the groundwork of a deal.
The Mexicans should "engage more intensively early in the process, so that you don't only rely on formal meetings but through bilateral contacts and frequent meetings in a smaller setting and an earlier understanding of how the process can be advanced," he told AP.
"At the moment, it tends to be very much a stop-and-start affair with everything concentrated in the formal negotiations, where I think a much more continuous engagement by (Mexico) is needed."
The partial agreement reached in Copenhagen, brokered by Obama, "was very significant," he said. But he acknowledged frustration that the deal was merely "noted" rather than formally adopted by all countries.
"We were about an inch away from a formal agreement. It was basically in our grasp, but it didn't happen," he said. "So that was a pity."
The media-savvy former Dutch civil servant and climate negotiator was widely credited with raising the profile of climate issues through his frequent press encounters and his backstage lobbying of world leaders.
But his constant travel and frenetic diplomacy failed to bridge the suspicions and distrust between developing and industrial countries that barred the way to a final agreement at the climate change summit in Copenhagen in December.
People who know de Boer say he was more disheartened by the snail-paced negotiations than he was ready to admit.
"I saw him at the airport after Copenhagen," said Jake Schmidt, a climate expert for the U.S.-based Natural Resources Defense Council. "He was tired, worn out." The summit "clearly took a toll on him."
Schmidt, speaking from Washington, said the Dutch diplomat was "very effective in pushing the envelope" and winning attention for climate change. "He's done a powerful job ... in getting the world to focus on this."
During de Boer's tenure, climate talks rose "to a standing item on the agenda of political leaders," said Oxfam International, a nonprofit group that monitors the talks and advises delegations. World leaders "could learn much from de Boer's perseverance as well as his uncompromising commitment to do what's necessary -- not just what's easy."
The German Green Party said de Boer's departure presented a chance for a strategic reorientation of his U.N. office.
"The failure of the Copenhagen climate conference was due partly to bad preparation and organization," the Greens' climate change specialist Hermann Ott said in a statement. "Now a credible and experienced successor has to be found to make sure the international process to combat climate change continues without delay."
De Boer, 55, was appointed in 2006 to shepherd through an agreement to succeed the 1997 Kyoto Protocol, which required industrial countries to cut greenhouse gas emissions an average 5 percent.
He said the high point of his efforts was the agreement by developing countries, reached at the 2007 conference in Bali, Indonesia, to join in efforts to contain global warming in return for financial and technical help from the wealthy nations.
The Bali meeting was so intense that during its final meeting, when he was accused of mishandling negotiating arrangements, de Boer walked off the podium in tears. He came back later to an ovation from the thousands of delegates.
His assertiveness sometimes led to accusations that he was overstepping the bounds of a neutral U.N. facilitator.
"They are absolutely right. I did that because I felt the process needed that extra push," he told the AP.
When he was hired, he said, he told U.N. Secretary General Kofi Annan, "If you want someone to sit in Bonn and keep his mouth shut then I'm not the right person for the job."
Yet De Boer habitually put a positive spin on events. Though he occasionally chastised governments, he did it in diplomatic tones. At times when his aides were describing him as "furious" -- especially with the administration of George W. Bush -- de Boer kept his public comments so modulated that it sounded like praise.
De Boer said he will be a consultant on climate and sustainability issues for KPMG, a global accounting firm, and will be associated with several universities.
"I have always maintained that while governments provide the necessary policy framework, the real solutions must come from business," he said in a statement released later Thursday. "Copenhagen did not provide us with a clear agreement in legal terms, but the political commitment and sense of direction toward 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," he said.
De Boer, who comes from a diplomatic family, was born in Vienna and traveled the world before attending a British boarding school. He studied social work at university in The Hague, and one of his early jobs was as a parole officer. He worked for the United Nations in Canada and Kenya, then joined the Dutch housing ministry. He has been involved in climate change issues since 1994, and three years later became the chief climate delegate for the Netherlands.
Associated Press Writer Verena Schmitt contributed to this report from Berlin.