Mayor Daley has been saying for years that he wants to make Chicago the greenest city in the country, but his environmental record is decidedly mixed.

After the mayor, no one has been as deeply involved in the administration’s successes and as evasive about its shortfalls as Sadhu Johnston, Daley’s chief environmental officer, deputy chief of staff, and frequent cheerleader.

But Johnston won’t be on hand to offer justifications or lead the applause for Mayor Daley much longer: he’s leaving at the end of this month to become the deputy city manager of Vancouver.