Environment & Energy

The first step is to acknowledge that this tradeoff exists. It’s well-known in the scientific literature but more general communication has aimed for simplicity. The message has been: “Particulate matter is a harmful pollutant that damages people’s (and ecosystems’) health. Reducing emissions will also be good for climate.” The tricky part is that the last part has exceptions like the lighter-colored aerosols. The same policies aimed at protecting health by reducing particulate matter often also contribute to climate mitigation because they reduce dark particles or co-emitted greenhouse gases, but not always.

Acknowledging the tradeoff allows us to factor it into policy discussions about air quality. That doesn’t mean we slow down on cleaning up the air. It would be kind of pathetic to hide from climate in a toxic fog when there are so many other options to limit warming and its impacts. But we do need to recognize that increased warming is a potential outcome of such policies and make plans for that.