“The Oceans will begin to boil…” – yes he actually said that, along with some other silly things. Watch this video:
One wonders, if Dr. Hansen realizes that no scientist has yet presented any credible evidence that the “oceans boiled” millions of years ago when atmospheric CO2 values far exceeded the 390 ppm we have now. Of course, given that this is a “Climate Progress World” production, such inconvenient facts don’t matter, as its all about the scare.
Hansen apparently has Venus on the brain. Even normally alarmist Wikipedia doesn’t embrace Hansen’s “runaway greenhouse effect” on Earth.
The situation on Earth is very different from that which existed on Venus, as any terrestrial runaway effect is not irreversible on geological timescales. Potential runaway greenhouse effects on Earth may involve the carbon cycle, but unlike Venus will not involve boiling of the oceans. Earth’s climate has swung repeatedly between warm periods and ice ages during its history. In the current climate the gain of the positive feedback effect from evaporating water is well below that which is required to boil away the oceans. Climate scientist John Houghton has written that “[there] is no possibility of [Venus's] runaway greenhouse conditions occurring on the Earth”.
h/t to WUWT reader “coldlynx”