Support Our Work
Blogs Section
Thoughts on everything from climate modeling to energy policy.

The Scariest Thing I’ve Ever Read About Climate Change, or Maybe Anything

By Philip Duffy

A new paper in the respected journal Nature presents a frightening analysis of sea level during the last interglacial period, roughly 125,000 years ago. This long-ago era is important to us today, because temperatures then are thought to have been very close to those projected for 2100 from a very modest climate change scenario, and very close to the 2-degree Celsius warming target that is widely discussed—and recognized as difficult not to exceed. In other words, the Last Interglacial gives us a picture of what our future might look like. And I don’t like it.

The new analysis by Robert Kopp of Princeton University and other scientists from Princeton and Harvard shows that this modest 2 degrees of warming results in global sea levels that are higher than today’s by somewhere between 6.6 and 9.4 meters. That’s 22 to 31 feet! And that 2-degree warming is compared to “pre-industrial” temperatures (i.e. before humanity started changing things), which means less than a degree from where we are now. This is not saying that sea level will rise 22 to 31 feet by 2100. This is saying that an amount of warming that could very well occur by 2100 will eventually (after centuries) result in 22 to 31 feet of sea level rise. The sea level rise happens very slowly because the deep ocean is isolated from the surface (so it will take a long time to warm and expand) and because—we hope—large ice sheets take a while to disintegrate.

But still.

It doesn’t take much imagination to see that 22 to 31 feet of sea level rise results in quite a different planet. Without massive flood-control engineering, large portions of Florida, the Gulf Coast, low-lying areas of Europe, and on and on, would be permanently submerged. Pacific island nations? Ancient history. And I am no engineer, but building walls against 20 or 30 feet of sea level rise sounds pretty difficult. And how close to one of those walls would YOU want to live?

The last two days of the Copenhagen talks might very well determine whether of not something like this will eventually happen. I hope this dismal scenario concentrates the minds of the diplomats and heads of state.


Annual Average Atlantic Hurricanes by Decade Hurricane Matthew threatens the Southeast through this weekend.

View Gallery