There's something funny about them reporting market-based emissions in the appendix. Mostly, that they're reporting them all the way back to 2011 when this was only approved by 2015. It's not really a big deal, but it's a bit unusual.<p>You can read a bit about the market-based scope 2 method here:<p><a href="http://www.wri.org/blog/2015/01/scope-2-changing-way-companies-think-about-electricity-emissions" rel="nofollow">http://www.wri.org/blog/2015/01/scope-2-changing-way-compani...</a><p>Let me explain a bit: market-based emissions are electricity power grid emissions computed the market-based method. The method measures your emissions differently depending on whether or not you bought a green instrument. Roughly speaking, green instruments are money you pay the power company that they will invest into green sources of energy, like wind and solar.<p>Under the market-based method, if you bought a green instrument, you can then report lower emissions, as if all of your electricity only came from the green energy you purchased. Conversely, if an instrument was available for purchase but you didn't buy one, your emissions will look like they all came from non-green sources of energy, like coal (these are called residual emissions). Of course, this is all a bit of an accounting lie: when you use the power grid, you can't tell the power company to not send you electricity from their coal power plant. Therefore, you also have to report your location-based emissions, which is the "normal" reporting that has been used in all previous years and is still being used. Roughly speaking, the location-based method is, take the total emissions of the entire power grid you're using, and multiply that by your fractional of the power usage of the grid over all other customers. Your emissions are then computed as your proportion of all green and non-green emissions that the entire power grid produces.<p>The market-based method is supposed to incentivise companies to buy green instruments because they can then report lower emissions under one method. The purchase of green instruments in turn is supposed to incentivise power companies to invest in green energy. The whole thing, however, is kind of based on an accounting "trick". This is why the greenhouse gas analysts at my job aren't huge fans of the market-based method.<p>WRI was pressured by many industry leaders to adopt the market-based method as part of the reporting protocol. If Google is reporting market-based emissions all the way back to 2011, way before it was approved last year, I wouldn't be surprised if they were one of the companies that lobbied WRI to include the market-based method. They are also mentioned as a motivating example in that link above.