of Global Environmental Change: Knowledge for the Sustainability Transition ” (Berlin, 7 December 2002). Research assistance by Devyani Kar and Joe Monfort, and helpful comments by Aarti Gupta, Peter Haas,

Global knowledge management is crucially dependent on public access to information – in particular, information on environmental risks. Yet most existing systems of governance favour administrative or corporate secrecy, thereby monopolizing environmental information in the hands of governmental authorities or private stakeholders. This paper describes innovative initiatives to establish civil society’s ‘right to know’, by mandatory disclosure of government-held information (from the 1966 US Freedom of Information Act to the 1998 UN/ECE Aarhus Convention) and of industry-held environmental risk data (through the worldwide spread of Pollutant Release and Transfer Registers, and through court-enforced access to ‘privileged ’ documentation – for example, on tobacco-related health risks). These disclosure strategies have triggered a ‘third wave ’ of environmental regulation, replacing or supplementing traditional command-and-control and market-based instruments. However, the paper also highlights continuing transparency deficits (sometimes resulting in ‘manufactured uncertainty’) with regard to risk-sensitive information of common concern. 2 Environmental governance is plagued by uncertainty, with regard both to bio-geophysical processes and to socio-economic costs and benefits (Arrow & Fisher 1974; Iida 1993; Harremoës 2000; Stewart 2002). Some of those uncertainties are exogenous, often incalculable, and we simply have to cope with them as risks and unknowns (Knight 1921, 19