The United Nations' climate diplomat has historically worked in the background as presidents, government ministers and celebrities made a public case for action.
But Yvo de Boer has been anything but a wallflower.
At last year's climate summit in Poznan, Poland, for example, college students jockeyed for opportunities to talk with the former Dutch housing official. Reporters regularly seek de Boer for clues about what is happening behind the curtain on the international stage.
And occasionally, de Boer has been chastised by diplomats from countries that pay his U.N. salary -- the United States, Japan and Saudi Arabia, to name a few -- for his blunt assessment of climate negotiations.
"I think the conventional role of a secretariat is to shut up and make sure things work," de Boer said. "I said in my interview to [then-U.N. Secretary-General] Kofi Annan, 'If that's what you want, then don't hire me.'"
De Boer works in the crossfire between developed and developing countries battling over terms of a treaty for curbing greenhouse gases. His job is getting tougher, with a major U.N. climate conference in Copenhagen, Denmark, looming in December and with many top officials openly questioning whether a successor treaty to the Kyoto Protocol can be completed this year.
For de Boer and his U.N. colleagues, efforts to kick-start the stalled talks have meant a major push this month at events in New York and Washington.
Last Friday, the Obama administration ended another round of the Major Economies Forum with environmental ministers from 17 countries that have the world's largest volume of greenhouse gas emissions. Tomorrow, President Obama will address a special climate session in New York. "He will underscore that this is very much a shared challenge, that everybody has to step up if we're going to succeed in making concrete progress," said Susan Rice, the U.S. ambassador to the United Nations.
All of this has de Boer in the spotlight again. These closing weeks of September, he said during an interview with E&ETV's Onpoint last week, "will give us a sense on whether Copenhagen is going to be a success or not."
In an office in Bonn, Germany -- on a street named for Martin Luther King Jr. -- de Boer manages 350 U.N. staffers and a two-year, $55 million budget. The office covers all aspects of the implementation of the Kyoto Protocol and organizes annual conferences aimed at crafting a new treaty.
But de Boer is not known for his day-to-day oversight of the U.N. climate bureaucracy. He is probably best remembered for leaving the 2007 negotiations in Bali, Indonesia, in tears. Like many other diplomats, de Boer had been working without sleep for two days.