The Secretariat of UNFCCC published a carbon footprint of its activities in 2006, covering 2004 and 2005. That footprint contained multiple material errors and has been removed from the UNFCCC website.
The greenhouse gas emissions of UNFCCC were about 25,000 tCO2 per year. In the 2008 carbon footprint this has apparently been reduced to 1,687.2 tCO2. How did they do it? I mean, even if you offset the emissions they still occurred. Did they ground all staff? Do they have their own fleet of biofuel-powered airplanes? Note also the precision - in 0.1 tCO2. Emission factors of IPCC have only 3 significant digits, and therefore the calculated CO2 emissions cannot have more than 3 significant digits either.