It strikes me that the companies that gain marketing value from going carbon neutral, buying RECs, etc. are inversely correlated to the companies that actually contribute to carbon emissions in a meaningful way - as your observation makes clear.  Whole Foods, Yahoo, etc. all get good PR from doing the right thing... but when all is said and done, their carbon impact is trivial.  By contrast, the really big emitters (power plants, steel mills, etc.) sell commodities that live or die by tiny price differentials and can't afford to invest in green PR.  Or, put another way, no one picks their rebar supplier based on their social responsibility.

I don't know how one breaks this, or even if one needs to - but it does call to question how much one ought to make of announcements like Yahoo's.  (Which isn't meant to knock Yahoo - just the reality of the situation.)  By contrast, we probably ought to give a lot more praise to the Dows and BPs of the world who have made significant efforts to cut their CO2, and while they started from a much higher number, I am willing to bet that the aggregate impact is much larger.

Food for thought, anyway.

Big kudos to Yahoo for going carbon neutral, but I must say I don't understand why they didn't do it by protecting tropical forests - they'd get a lot more bang for the buck in terms of both carbon saved, biodiversity protected, and social benefits than working with huge financial interests to install hydropower and wind turbines. And people would understand it more easily. Hopefully, they'll choose that option in the future.

Maybe you should get a 'carbon offset,' but you are way, way behind on 'posting offsets.'   You owe big time here on that.

The only way Yahoo can be carbon neutral is to remove 250,000 metric tons of carbon from the atmosphere each year and bury it in a way that will keep it SAFELY isolated for at least several hundred thousand years. They should also bury equivalent amounts of mercury, cadmium, arsenic, sulfur, uranium, NOx etc.

At best this should be called carbon dilution.

We should put a price on all emissions reflecting our best estimate of the cost of the damage they do, and let the market select winners and losers.

Yahoo could have shown itself to be a leader by pushing forward on avoided deforestation in Indonesia.  Instead it demonstrates yet again why it plays second fiddle.