A new study out this week calls on policymakers and green activists to abandon what has become the focus point for most climate policy endeavors these days: the goal of limiting surface warming to 2 degrees Celsius. Scientists have suggested that, beyond this 2 degree threshold, a number of potentially devastating feedback loops could kick in, leading to some very tough problems for humanity. But according to the authors of this new study, setting a single target (conveniently a whole number) is a poor way by which to make policy. Reuters reports:
“Politically and scientifically, the 2 degree C goal is wrong-headed,” David Victor and Charles Kennel, both professors at the University of California in San Diego, wrote in the Nature article entitled “Ditch the 2C Warming Goal”. […]The study urged a shift to other yardsticks to gauge the planet’s health, such as concentrations of greenhouse gases in the atmosphere or changes in the heat content of the oceans.
The authors compared the process of assessing the status of our planet’s climate to that of gauging the health of a human being. Just as a patient getting a physical at a doctor’s office will be a subjected to a battery of tests, not just have his or her temperature taken, the authors argued that “[a] similar strategy is now needed for the planet.”Because it’s so simple, the 2 degrees Celsius target has been politically expedient. But our climate is anything but simple; in fact, it’s one of the most complex systems we study. Metrics can be useful tools for target-setting and the like, but relying wholly on a single number is the proverbial mistake of putting all of one’s eggs in a single basket.We’ve seen a pause in warming over recent years that has defied the predictions of all of our best climate models. There is clearly much we don’t understand about our climate, notably about the rate at which it might warm. The study’s authors suggest expanding our toolbox of metrics to include greenhouse gas concentrations and oceanic heat sinks, and that’s to the good, but we ought also to approach climate policies with a bit more humility, as well. Yes, our planet is warming, and yes, humanity bears responsibility for that. Unfortunately, beyond that, the so-called “settled” science begins to break down.