Yvo de Boer's career as UN climate chief

Yvo de Boer at the UN climate summit in Copenhagen in December, 2009. De Boer described his team's role in thrashing out a successor to the Kyoto protocol as 'the butlers of the process' – expert yet unobtrusive – yet he also styled himself 'the conscience of the process' – moral, insistent and occasionally annoying
Photograph: Keld Navntoft/AFP/Getty Images

Archbishop Desmond Tutu hands De Boer a petition signed by 512,894 people. De Boer wrote optimistically in 2008 that 'countries have agreed to clinch a new international climate change deal in Copenhagen,' but critics condemned the final deal as a 'failure'
Photograph: Christian Charisius/Reuters

The 2007 UN climate summit in Bali, Indonesia. As talks drag on, De Boer buries his face in his hands – and ultimately had to be led from the chamber in tears. The UN secretary-general, Ban Ki-moon (left), and Indonesian president, Susilo Bambang (right), look on – not entirely sympathetically. De Boer's tears 'helped force US negotiators into a crucial compromise'
Photograph: Mast Irham/EPA

De Boer in a more playful mode at Copenhagen. His tears at Copenhagen and general tendency to wear his heart on his sleeve earned him the nickname 'the Crying Dutchman'
Photograph: Bob Strong/Reuters

De Boer walks past members of the environmentalist group TckTckTck in Copenhagen
Photograph: Miguel Villagran/Getty Images

De Boer has said that he never ceases to be amazed by the vision that some people have of the UN. 'To me it is a collection of countries that have created a body to facilitate negotiation among each other. If those governments were to go and negotiate in a different setting with a different secretariat I don't know if that would fundamentally change their behaviour'
Photograph: Miguel Villagran/Getty Images

De Boer emerges from a 'Solar Taxi' in Poznan, Poland, in 2007. Ever an optimist, De Boer admits Copenhagen 'didn't produce the final cake' but says it did leave countries 'with all the key ingredients to bake a new one'
Photograph: Joe Klamar/AFP