Gavin Schmidt suggests that with another 8 ppm of CO2, sea levels will rise 65 feet?

Twitter / ClimateOfGavin: Pliocene, perhaps 400ppm CO2 ...

Pliocene, perhaps 400ppm CO2 (today we are at 392ppm), around 3°C warmer, sea level: +20m?
http://nyti.ms/10k35bE