I wrote, “Even in 1988 it was common knowledge that CO2 (the most important of the GHGs they discussed) has a logarithmically diminishing effect on temperature.”
ATTP replied, “I’m pretty sure that Hansen was well aware of this.”
I then quoted Hansen 1988 saying, “the assumed annual growth averages about 1.5% of current emissions, so the net greenhouse forcing increases exponentially,” and noted, “We all know that’s wrong.”
But izen proved me wrong, saying, “it is not false.”
So obviously not “all” of us know it. But I know it, and Ken knows it, and presumably even Hansen knows it, now.
izen continued, “Read more carefully, Hansen says… “net greenhouse forcing increases exponentially“ … Not CO2 forcing, the NET forcing, so including water vapour as a positive feedback and CFCs…”
Water vapor feedback doesn’t turn an asymptotically linear forcing into an exponential one. It just makes the linear slope steeper.
CFCs are another example of the many glaring errors in that paper. The Montreal Protocol was agreed upon in 1987, and the Vienna Convention in 1985, so there’s no excuse for Hansen 1988 (published August 1988) nevertheless projecting exponential increases in CFCs. That’s yet another way in which Hansen and his seven co-authors were wildly wrong about almost everything.
izen continued, “we are seeing unprecedented warming, sea level rise… over the last 30 years…”
Unprecedented? Really? Which of these two half-century temperature graphs do you think is “unprecedented,” and which is natural?
And sea-level rise? Do you really think the right-hand bits of the following graphs show “unprecedented” sea-level rise?
The first two graphs show typical trends from especially high-quality measurement records, on opposite sides of the Earth (12 time zones apart, during summer), at sites little affected by known distortions like tectonic instability, vertical land motion, and ENSO.
The last two graphs are from two sites which experience so much PGR that “sea-level rise” is negative, illustrating the fact that the global trend is so tiny that in many places it is insignificant, because it is dwarfed by common coastal processes, like vertical land motion, sedimentation, and erosion.
However, when I show climate alarmists graphs like those, they usually accuse me of cherry-picking. So here’s NOAA’s full 2016 list of 375 long term trend tide stations:
As you can see, none of the best-quality, long, sea-level measurement records show appreciable acceleration since the 1920s, or before.
izen continued, “…the egregious distortion of Hansen you attempt…”
I distorted nothing, and you surely know it. That sort of nastiness is destructive to scientific dialog. Please stop it.