Thanks to reader Joe, who writes:

Spotted this in Chicago on my way to the Daley Center. If you look closely, the sticker says “This car’s CO2 is offset by terrapass.” Naturally, the window sports a Northwestern decal as well. Unsurprisingly, Terrapass’s slogan is “Fight global warming, reduce  your carbon footprint.”

Love your bumper sticker series so I thought I’d contribute. I – shockingly – spotted a bumper sticker in Chicago that said “Work harder! Millions on Welfare depend on you!” Unfortunately, he wasn’t in front of me long enough to snap a picture.

Joe, no problem on the “millions on welfare” miss, we got it covered.

As to the carbon offset industry, what possibly could go wrong?