The longer version may be downloaded at www.olis.oecd.org/olis/2009doc.nsf/LinkTo/NT00006E9E/$FILE/JT03274406.PDF. Policy reform (as opposed to incremental change) in the environmental arena almost always requires the use of economic instruments, albeit often in conjunction with other instruments. This may be due to the central place in environmental economics of the concept of the “externality”, with the advice that this should be “internalised” into the price, and the most obvious and often the most efficient way to this is through an economic instrument.