Slate: Did I Say 30 Billion Tons of CO2 a Year? I Meant 40.

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Did I Say 30 Billion Tons of CO2 a Year? I Meant 40.
http://www.slate.com/blogs/bad_astronomy/2014/08/20/atmospheric_co2_humans_put_40_billion_tons_into_the_air_annually.html

---Steve