Simple question for Andy Revkin, who claims to be a "fan" of some voluntary carbon dioxide offset projects: Over the last five years, what percentage of your own income have you voluntary spent on CO2 offsets?

Action Plans on CO2 that Go Beyond 'Woe is Me, Shame on You' - NYTimes.com

I’m a fan of voluntary offset projects of this sort where the added value of a payment goes far beyond avoided greenhouse gases.