Letter to the Editor
Dear Editor,
Holman W. Jenkins Jr.’s September 7th column, “CNN Climate Show Wasn’t Just Boring,” invokes the recently deceased Martin L. Weitzman and our joint book to suggest CNN’s climate town hall missed the mark in assuming that the climate is in crisis. CNN didn’t miss the mark, because climate change is a crisis. Weitzman would have been the first to say so.
Yes, in prior articles as well as in Climate Shock, Weitzman and I calculated a probability of around 10% of eventual global average warming of 6 degrees Centigrade (11F). In fact, we emphasize that scientists cannot fully imagine, much less quantify the planetary catastrophe that 6 degrees of warming would bring.
But the climate crisis does not begin at 6 degrees. For example, last time concentrations of carbon dioxide were as high as they are now—past 400 parts per million—sea levels were at least 20 meters (66 feet) higher than they are today. Unlike 3 million years ago, today there are cities, states and entire island nations who would be submerged.
Even with warming already experienced, we are feeling plenty of costly impacts, from sea level rise to wildfires. Because as Weitzman’s work on climate tail risks and research from the broader scientific community shows, only small increases in averages can mean large increases in extreme events.
Climate is a risk management problem, or at least it should be seen as one. And the impacts are already severe enough to warrant much deeper emissions cuts than are currently on the table.
Sincerely,
Gernot Wagner
New York University