Al Gore delivers his Nobel Lecture during the Nobel Peace Prize Award Ceremony at the Oslo City Hall, Norway, on 10 December 2007.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Dr Rajendra K. Pachauri, Chairman of the Intergovernmental Panel on Climate Change (IPCC), gives his Nobel Lecture during the 2007 Nobel Peace Prize Award Ceremony.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Professor Ole Danbolt Mjøs, Chairman of the Norwegian Nobel Committee, introduces the Nobel Peace Prize Laureates at the 2007 Nobel Peace Prize Award Ceremony.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Nobel Peace Prize Laureates Rajendra K. Pachauri (representing the IPCC) and Al Gore listen to the introductory speech during the 2007 Nobel Peace Prize Award Ceremony.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Nobel Peace Prize Laureates Rajendra K. Pachauri (representing the IPCC) and Al Gore are interviewed by Jonathan Mann of CNN.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Al Gore, 2007 Nobel Peace Prize Laureate, signs the guest book at the Norwegian Nobel Institute.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Rajendra K. Pachauri signs the guest book at the Norwegian Nobel Institute.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Al Gore and his wife, Tipper, greet the crowd who have gathered outside the Grand Hotel in Oslo, Norway, at the end of a torchlight procession.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Rajendra K. Pachauri and his wife, Saroj, wave to the crowd from the balcony of the Grand Hotel in Oslo, Norway.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

The 2007 Nobel Peace Prize Laureates and their spouses with the Norwegian Royal Family at the Royal Palace in Oslo, Norway (from left to right): Their Royal Highnesses Crown Prince Haakon and Crown Princess Mette-Marit of Norway, Rajendra K. Pachauri, Saroj Pachauri, Tipper Gore, Al Gore, and Their Majesties King Harald V and Queen Sonja of Norway.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Al Gore delivers his speech during the 2007 Nobel Peace Prize Banquet.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Rajendra K. Pachauri addresses the guests at the 2007 Nobel Peace Prize Banquet.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Al Gore and Rajendra K. Pachauri are among the audience at the Nobel Peace Prize Concert. Artists from all over the world have gathered at the Oslo Spektrum in Norway to honour the 2007 Nobel Peace Prize Laureates and help spread a message of peace.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Kevin Spacey and Uma Thurman host the 2007 Nobel Peace Prize Concert, which is broadcast to more than 100 countries worldwide.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Kevin Spacey, Annie Lennox, Uma Thurman and Melissa Etheridge dancing on stage at the 2007 Nobel Peace Prize Concert.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann

Pop icon Morten Harkett serenades the audience at the Oslo Spektrum in Norway.

© The Norwegian Nobel Institute 2007, Photo: Ken Opprann