Activities by the United Nations in 2009 caused the emission of a total of 1.7 million tons of the greenhouse gases, which are blamed for global warming and harmful effects on the environment and human health, the world body said in a new report unveiled Friday.

The report, Moving Towards a Climate Neutral UN, details the greenhouse gas emissions for 52 UN institutions, covering 200,000 employees. It is published as part of ongoing efforts to reduce the UN's carbon footprint.

More than 50 per cent – 4.1 tons per capita – of the UN emissions are from air travel, making staff movement the biggest challenge for the Organization in reducing its overall carbon footprint, the report points out. About 37 per cent of emissions are from buildings and 13 per cent from vehicles.

In a foreword to the report, prepared by the UN Environment Programme (UNEP), Secretary-General Ban Ki-moon states that improving the UN's in-house sustainability performance will make the world body more efficient, more effective and less exposed to risk.

"The United Nations has played a key role in elevating the profile of climate change on the international agenda, and continues to support Member States in their efforts to reduce emissions, strengthen adaptation and respond to this immense global challenge," writes Mr. Ban.

"Such work has a natural complement in our in-house drive to reduce the UN's own carbon footprint. What we demand of others, we must do ourselves."

The report provides a progress update on implementation of the UN's Climate Neutral Strategy.

The strategy was approved the UN Chief Executives Board (CEB) in October 2007 and commits all agencies, funds and programmes to move towards climate neutrality within the wider context of "greening" the UN.

The strategy requires UN bodies to estimate their greenhouse gas emissions, undertake efforts to reduce greenhouse gas emissions and analyze the cost implications of purchasing carbon offsets.

The emissions calculations in the report are based on the Greenhouse Gas Protocol, a widely used methodology developed by the World Resources Institute and the World Business Council for Sustainable Development.

The UN greenhouse gas inventory includes emissions from all activities that are under the direct financial control of the Organization, such as the heating and cooling of buildings and the travel of staff members. The UN International Civil Aviation Organization's (ICAO) Carbon Emissions Calculator was used for computing the air travel portion of the greenhouse gas inventory.

The report highlights recent "greening" the UN efforts and details the myriad ways in which UN entities, staff associations and individual employees worldwide are continuing efforts to reduce their greenhouse gases emissions.