# **Appendix 1: Carbon Footprint Calculations for WBG Air Travel for Fiscal Year 2012 (FY12)**<sup>**32**</sup>

We have had available about 90 percent of the total data for the air travel activity for the entire WBG, both for headquarters and for field offices, for the period March 2011 – February 2012. This data set contains a total of 322,331 trips covering about 642 million miles, of which roughly 57% were trips ticketed by Amex at headquarters.<sup>33</sup> The actual, total traveled distance by the entire WBG in FY-12 (July 2011-June 2012) was 677 million miles, or about 3.2 percent lower than the 699 million miles flown in CY09. Here, all calculations are made on the (slightly more limited) data set available to us. When making the carbon footprint calculations for FY-12, in Section 5.4, our calculated data are scaled up with an expansion multiplier of 1.055 (the relative increase necessary to represent the entire FY-12 flight activity).

The breakdown of FY-12 travel by class can be found in Table A1.1 below. For FY-12 there is very little known first class travel, in contrast to CY-09 where such travel comprised almost 8 percent of all HQ-booked trips by WBG staff. This is due to a changed and standardized policy whereby first-class travel is authorized only in extremely few cases. “Economy” and “economy plus” trips are combined under the single category “Coach”. We have no information about the “unknown” class category, and simply assume that its class-specific distribution is the same as for the “unknown” category.

In 2012 only 0.1% of miles traveled by WBG staff were, officially, on first class (assuming again that first class does not appear more frequently in the “unknown” category).<sup>34</sup> This almost disappearance of first class as a separate flight class category for WBG staff is treated by us, for practical purposes, by simply calculating the footprint with one common load factor for both business and first class. The mistake made when doing this will be very small, on the order of less than 1 percent of the overall footprint.

In Table A1.1, the “unknown” category implies that we cannot be certain about the overall distribution of travel by class. We however find no reason to assume that the distribution of the “unknown” category is different from that for known categories. On this premise, 48.4% of miles on CO-booked travel, 79% on HQ-booked travel, and 66.1% of total miles traveled were in business class, so that the complements (51.6%, 21% and 33.9%) were in coach class (ignoring as noted first-class travel which constituted only about 0.1% of total travel). For HQ-based travel in CY-09, in Table 5.1, comparing to numbers in Table A1.1 we find a slight reduction in the fraction of business class in 2012 (79%), as compared to the aggregate of business and first

> 32 In WBG terms, this fiscal year starts July 1, 2011, and ends June 30, 2012.

> 33 In addition there are approximately 60 million traveled miles, where we do not have this detailed breakdown. We will in the following simply assume that these “unknown” miles have the same relative distribution, by traveled length, class and by HQ- and CO-base, as those accounted for.

> 34 Note however that we only have information about booked travel, and not actual flight activity. In practice there may be some on-the-spot upgrading both from coach class to business class, and from business class to first class. To the extent that this takes place, this factor will also bias our figures downward relative to their true values .

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