By John Rennie
Posted: December 12, 2013
To hear Jeffrey D. Sachs tell it, if humanity manages to avert catastrophic warming from manmade greenhouse gases, it won’t be because of an astonishing technological breakthrough that suddenly saved the day. It will be because policymakers mustered the will to start acting today rather than later, and focused on how to transform global energy systems before squabbling about who should pay for it.
Unfortunately, that has not happened yet. “What we have is mostly a debate about what’s fair and unfair, but very little understanding about what to do,” he says.
Sachs, renowned as an economist and advocate for sustainable development, is director of the Earth Institute at Columbia University and of the U.N. Sustainable Development Solutions Network, and special adviser on the Millennium Development Goals to U.N. Secretary General Ban-Ki Moon. He is also a coauthor, with climatologist James Hansen and a multidisciplinary team of other specialists, of a recent report in the journal PLOS ONE that made a plea for 1 degree Celsius, not 2 degrees, as the appropriate ceiling for permissible warming in the future.
To get his impressions of the report’s content and of its policy implications, I spoke with Sachs a few days before the paper’s publication. What follows is a summary of that conversation.
2 °C is too much
Asked to describe the PLOS ONE report, Sachs calls it “one of the best, concise, up-to-date summaries” of current scientific understanding about the state of the warming problem, drawing on paleoclimate data, climate models, and empirical tracking of global temperatures. (He is also quick to credit it primarily to Hansen, who led the work.)
All those indications, Sachs says, lead to the same conclusions: that the impacts of climate change are already being felt, that they will multiply tremendously in the future, and that feedbacks in the climate system could greatly amplify both the future warming and the consequences associated with it.