|The Global Greenhouse Regime. Who Pays? (UNU, 1993, 382 p.)|
|Part I Measuring responsibility|
|2 The basics of greenhouse gas indices|
Apples and oranges
Conclusion: indices do matter
Kirk R Smith
Deciding which greenhouse-gas emissions reduction or absorption projects to fund and which countries should contribute to the cost implies the use of indices to weigh the comparative net greenhouse gas (GUI) implications of potential projects and the net emissions of nations. These indices should be composed of individual indicators that are deemed to be relevant according to the criteria of scientific validity, economic efficiency, political equity, ease of use, and flexibility. The application of the appropriate index should not only rank but, preferably, also give a quantitative indication of how much better one project is over another or how much more one country should contribute than another.
Most of the indices that are used to determine accountability contain the structure, 'net greenhouse gases emitted per unit', where the unit is nation, population, income, energy use, etc., depending on the intended application. There are several important considerations and implications in choosing these various index denominators as will be discussed in Chapters 3 and 4.
Nearly all the indices also require the careful choice of appropriate numerator, the method by which the different greenhouse gases are weighted so that they can be compared or aggregated.