How green is our laptop?

[Ian Stirling]

Ian Stirling wrote:
> Jim Gettys wrote:
>> We've been very concerned about the "green" of our laptop, as we know
>> that it may not be recycled properly.  Obviously, a smaller/lighter/more
>> rugged/longer lived machine has a lot of advantages as well in this area
> <snip>
>> The very low power consumption of the machines means way less global
>> warming due to electricity usage.
> 
> Beware, I'm bored, and have the Internet!
> 
> Say average child flatulence is 1l/day - sources I found said 200ml-2l, 
> I'm assuming 1l, as diets high in vegetables are more likely to cause an 
> increase.
> Assuming that methane is 7%, this is about 150ml/day. (I found several 
> sources saying 7-9%, though some dismissed it as 'trace'. No primary 
> literature.)
> 
> Assuming the '20 times more potent than CO2' is accurate - equivalent to 
> 3l/day of CO2.
> If we're talking 10Wh/day, how much of the food is used to produce 
> electricity?
> Well, if we're talking 1000Calories per day baseline food, that's 
> 4MJ/day, or around 1% before taking into account human efficiencies. As 
> I see 25% as a rough 'maximum food conversion efficiency, that means 
> somewhere on the order of 4% more food, or 120g of CO2 equivalent per day.
> (I'm assuming that the food is being produced in a carbon neutral manner.)

Err.
Spot the comedy three orders of magnitude error.
Methane is slightly less dense than water.