The story so far: the scientifically and climatically inept Dr Jarrod Gilbert pontificated hysterically that it should be a crime merely to discuss ambiguities in the theory of dangerous anthropogenic global warming (DAGW), taking the view that only “those who deny climate change” cause doubt. He says reasonable doubt doesn’t exist, which of course is flagrant nonsense—just as no sceptics deny that climate change exists.
Dr Chris de Freitas responded, rebuking the academic for wanting to silence his critics by trampling on free speech—make it an actual crime? De Freitas pointed out: “Four billion years of global climate history shows that negative feedbacks prevail.” Earth has never experienced unbridled warming or cooling. It’s called “runaway warming” for good reason—because it would only happen once.
Then Dr James Renwick sent a letter to the Herald that accuses de Freitas of “misinforming people to downplay the risks they face”, blatantly ignores the fact that runaway warming can only occur once and wonders how de Freitas can see nothing to worry about.
My post, Renwick weak in climate quarrel, then attacked the four points Renwick put forward as “evidence” that we need to worry about climate change.
So Simon jumped in to attack my comments and, although he came up with a few good points, he makes mistakes. Others have given good and interesting responses, but here is my tuppence-worth. He says:
If the long-term rate of sea level rise is around 1.8 mm/yr and the current rate is over 3 mm/yr then there probably has been acceleration 🙂
All right, he gives us a little smiley face here, to show he’s tongue-in-cheek, for the simplicity of the logic. Nice. But the two figures come from different instruments, so there’s no acceleration (sorry). Tide gauges report about 1.8 mm/yr and the satellite altimeters about 3.2 mm/yr. Nobody knows why, but in the middle of the ocean, where only the satellite altimeters operate, sea level is rising faster. Along the coast where people live it’s been half that for about 140 years. Neither series shows recent acceleration and you can’t logically join them.
There is no reason why sea level rise or ice melt should be linear, evidence suggests it is not.
Actually, evidence says it is linear, but why do you think it’s important?
If you do a test on the full range of UAH data you will find a statistically significant rise.
The rise is greater on the Earth’s surface, where we all live.
Even if you provide evidence for that, I don’t believe you’ll give us reason to worry.
Greenhouse warming from increased water vapour is an observable positive feedback.
This has taken most of my time to investigate. First, it’s a theoretical feedback, from climate models. But, although the evidence is mixed, atmospheric water vapour has not been seen to rise, but to fall. In any case, as global mean surface temperature has not risen significantly, if atmospheric water vapour rose, temperature increase could not have been responsible.
Extremely likely means > 95% probability in general statistics and AR5, not ‘it’s possible’.
Yes, but a probability means it’s possible, but it is not certain. The probability of an apple falling to the ground after I drop it is 100%, not 95%. Extremely likely it may be, but that means, by definition, that it’s uncertain. So the point is that if they’re not prepared to say it’s certain, it’s not evidence and they can keep their filthy hands off our electricity bills.
Climate models are constantly being validated and refined.
That would be nice. So why are they so wrong?