As we say in this intro to this week's episode the question isn't "why are marketers talking about environmental issues", but "why haven't we spoken about it sooner"? Sustainability and activities on behalf of our planet are at the centre of many brands' activities, but even for those where that isn't the case, it is at least a growing concern. So how do we speak on behalf of brands around sustainability - and how can marketers lead the way on environmental issues?