On our first environmental project 10 years ago we used a tool called the Material And Products Screening Matrix. There may be better and more objective tools available today, but the complexity of the issues involved seem to be doomed to a heavy dose of subjectivity.
Using this Matrix we found that some of the usual choices of materials were as green as we were able to provide because of codes, availability and cost constraints.
Here is how the matrix is used. First fill in the background information at the top of the sheet. Second, select the Material Resource Type from the column on the left; and, using the given grade and the legend as a guide, establish the type of material and the grade you would assign to it. The third step is to grade the material (using just the row of the Resource Type that you settled on) in the nine criteria in the column headings. The next step is to add up the score and mark its total. The final step is to compare the score to the other materials under study, giving some consideration to the the Resource Type.
Since this process is almost entirely subjective we found that it was best for either one person or a small team acting as a group to grade all the choices under study. If you delegate different material evaluations to different people the subjectivity becomes too questionable to defend.
You can download the Material And Products Screening Matrix with this link.