Public procurement has been considered one of the key policies that could be used to promote changing unsustainable patterns of consumption and production.  Paragraph 4.23 of chapter 4 of Agenda 21 calls for governments to exercise leadership through government purchasing.  It is addressed in element C of the CSD Work Programme on Changing Consumption and Production Patterns adopted at the third session of the CSD in 1995.  The 1997 Programme for the Further Implementation of Agenda 21 further encourages Governments to take the lead in changing consumption patterns by improving their own environmental performance with action-oriented policies and goals on procurement, the management of public facilities and the further integration of environmental concerns into national policy-making.  More recently, the Plan of Implementation adopted at the World Summit on Sustainable Development calls for promotion of public procurement policies that encourage development and diffusion of environmentally sound goods and services. 

      Government spending on goods and services accounts for typically 15-30 per cent of GDP.  For OECD countries, total procurement (consumption and investment expenditure) for all levels of government amounts to a total of about $4.7 trillion in 1998. For non-OECD countries it is estimated at $816 billion.  The public procurement is diverse and covers a wide range of goods and services, from consumable goods to capital goods, infrastructure, construction and services.  All levels of government are involved in public purchasing. 

            Directing government spending to sustainable public procurement has a number of benefits: it reduces the negative impacts of government operations and increases the benefits; it expands or creates broader markets for goods and services that support sustainable development; it serves as a model for other consumers; and it offers standards and information for use by other consumers. It is often politically attractive in that it responds to public demand for governments to be environmentally and socially responsible in their own operations.