So, if the world???s energy consumption is 18000 terawatt-hours (per year) & Google is 2.6 terawatt-hours (per year) then this equals 0.014r% or the world???s energy consumption.

Or as Google says ???2.26 kWh per user per year or 188 watt-hours per month. That???s about the same as using a 60W light bulb for 3 hours (180 watt-hours)???. This is based on their 1 billion users.
Not bad for something we all rely on so heavily!

Regarding carbon credits, all this really does is push the problem around. What needs to happen is that we become more energy efficient. If you're interested in improving the energy efficiency of your data center or building, I highly recommend you have a look at this website. They offer free online energy efficiency training.

http://www.schneider-electric.com.au/sites/australia/en/company/energy-university-free-online-training.page