Imagine you’re an urban planner. Now imagine your employer has recently committed to becoming net zero by 2050. There’s a big new project on your desk. Your material and technological needs are vast, as are the available options. Given your new carbon targets, how do you assess which options will produce the least emissions in the long term? The short answer is that you can’t right now. Or at least you can’t do it in a way that is scientifically sound or broadly consistent. That could change. After their last meeting in Sapporo, Japan, in late April, environment ministers from the G7 advanced economies endorsed a “credible mechanism” to assess the comparable emissions profiles of different products and services, saying it could “mobilize financial resources to accelerate the deployment of solutions.” The official communiqué comes with two important caveats. First, any such mechanism must be “reliable, comparable and verifiable.” Second, it must help promote action by consumers, companies and investors to accelerate “effective emission reductions,” meaning it must not be used simply to sell more products. The World Business Council for Sustainable Development (WBCSD) is backing such a mechanism. The Geneva-based trade network says it would help producers of low-carbon products credibly differentiate their products from those that are less climate-friendly. Dominic Waughray, executive vice president of the WBCSD, said in an interview that an emphasis on avoiding emissions rather than reducing them would unlock a competitive race for ever-smarter eco-innovations, which would in turn accelerate the drive to meet global climate goals. (REUTERS/Benjamin Westhoff)