February 12, 2010 
Here is Richard Sommerville’s response to Climate Change Denialism with a h/t to Rabett Run.
1. The essential findings of mainstream climate change science are firm. This is solid settled science. The world is warming. There are many kinds of evidence: air temperatures, ocean temperatures, melting ice, rising sea levels, and much more. Human activities are the main cause. The warming is not natural. It is not due to the sun, for example. We know this because we can measure the effect of man-made carbon dioxide and it is much stronger than that of the sun, which we also measure.
2. The greenhouse effect is well understood. It is as real as gravity. The foundations of the science are more than 150 years old. Carbon dioxide in the atmosphere traps heat. We know carbon dioxide is increasing because we measure it. We know the increase is due to human activities like burning fossil fuels because we can analyze the chemical evidence for that.
3. Our climate predictions are coming true. Many observed climate changes, like rising sea level, are occurring at the high end of the predicted changes. Some changes, like melting sea ice, are happening faster than the anticipated worst case. Unless mankind takes strong steps to halt and reverse the rapid global increase of fossil fuel use and the other activities that cause climate change, and does so in a very few years, severe climate change is inevitable. Urgent action is needed if global warming is to be limited to moderate levels.
4. The standard skeptical arguments have been refuted many times over. The refutations are on many web sites and in many books. For example, natural climate change like ice ages is irrelevant to the current warming. We know why ice ages come and go. That is due to changes in the Earth’s orbit around the sun, changes that take thousands of years. The warming that is occurring now, over just a few decades, cannot possibly be caused by such slow-acting processes. But it can be caused by man-made changes in the greenhouse effect.
5. Science has its own high standards. It does not work by unqualified people making claims on television or the Internet. It works by scientists doing research and publishing it in carefully reviewed research journals. Other scientists examine the research and repeat it and extend it. Valid results are confirmed, and wrong ones are exposed and abandoned. Science is self-correcting. People who are not experts, who are not trained and experienced in this field, who do not do research and publish it following standard scientific practice, are not doing science. When they claim that they are the real experts, they are just plain wrong.
6. The leading scientific organizations of the world, like national academies of science and professional scientific societies, have carefully examined the results of climate science and endorsed these results. It is silly to imagine that thousands of climate scientists worldwide are engaged in a massive conspiracy to fool everybody. The first thing that the world needs to do if it is going to confront the challenge of climate change wisely is to learn about what science has discovered and accept it.
The problem of course is that denialists will just deny each point. They will claim he posts no evidence and even if he did, they would claim the evidence was doctored. Denialists are not the proper targets of course. The undecided and the honest skeptic are and perhaps the more objective journalists.
Le sigh.
It is useful though to have this kind of response in one place. I’d like to see some evidence attached to it and responses to anticipated objections to denialists. That would be good to use as a primer for educational purposes, but I’m afraid that climate science is now so discredited due to the CRU emails and related spin and publicity and of course, recent “IPCC Gates”, that it will take some time and more solid evidence for the tide of public opinion to turn.
The Policy Lass 
Susann,
It is good to see you have taken my advice and no longer attempt to claim you are seeking facts that may help you change your opinion on CAGW. Honesty is always the best policy.
As I said several times, there is no solid reason for me to reject AGW and until there is, there is every reason to support it. I’m talking about the science of AGW, not the scientists, their foibles, their personalities, and the usual mistakes in data or calculations.
But, I’d love to see some solid evidence against AGW. It’s just not there as far as I can tell and based on what you and other “skeptics” have claimed. You’re free to provide it anytime you find it, but appeals to authority and uninformed opinion with no evidence backing it up just won’t cut it.
No one denies climate change, Shewonk, except for Michael Mann and The Team… at least for the proceeding 1,500 years before 1900!
In spite of the fact that you are mainly bashing a straw man…no one seriously believes the climate is in stasis, (“climate change” is a tautological nonsense and “stopping climate change” is oxymoronic..)
There are plenty of good reasons to doubt an AGW apocalypse is going to occur this century. That’s the real question, isn’t it?
Perhaps the most persuasive is the paleoclimatological argument which goes something like this: If it was as warm about a thousand years ago as today, or warmer, then why do we need a special one-off theory to explain modern warming?
In fact, the Principle of Parsimony suggests that we do not. This basic logical principle of hypothesis construction was well understood by The Team when they proposed to essentially erase the MWP and replace it with a mythical “climate stasis.”
Only by being in DENIAL over the true amplitude of historic natural climate variability can one rationally accept the AGW hypothesis as valid and useful. If the MWP and the LIA aren’t figments of imagination, then today’s warming must be considered natural until proven otherwise, since “climate change” on the scale experienced in the 20th century is well within the normal range.
And Shewonk makes one other major logical error in her Feb 13 9:04am reply, with seems to reveal a somewhat weak grasp of the scientific method as it has been practiced since The Enlightenment.
No, Shewonk, the skeptics are not required to “provide solid evidence against AGW” theory. It works exactly the other way around. The supporters of AGW hypothesis must prove their hypothesis meets the rigorous challenge of producing useful predictions both forward and backward in time. If a single “implication” of the AGW hypothesis is shown to be false then the hypothesis itself must be modified or scrap and a new one drawn up which better fits observations.
The AGW hypothesis can not explain why the climate was as warm or warmer 1,000 years ago as it is today.
In fact, an implication of the AGW hypothesis is that due to the much higher level of atmospheric CO2, today’s temperature MUST be much greater than at any time in the past 20,000 or so years. This is demonstrably false and therefore the whole theory of AGW is based on a false premise.
“If it was as warm about a thousand years ago as today, or warmer, then why do we need a special one-off theory to explain modern warming?”
Simple: because all known natural forcings point downwards for the last 40 years. And because we have a pretty good understanding of what increased CO2 does.
The AGW hypothesis does not need to explain why it might(!) have been as warm a 1,000 years ago as it is now. It’s not part of the equation. It is exactly one of those things that may be fully explained by natural forcings, but we can’t go back so many years to measure them exactly.
In other words, the AGW hypothesis does NOT claim that “today’s temperature MUST be much greater than at any time in the past 20,000 or so years”. It will depend on the forcings.
That you don’t understand this, is most likely due to your preferred sources of information.
No one denies climate change, Shewonk, except for Michael Mann and The Team… at least for the proceeding 1,500 years before 1900!
Yawn. Been there, refuted that canard. Please use a better talking point — they won’t work here.
Again, yawn. Have you read anything or are you just a parrot, reading off a cue card?
Sorry — but your post really doesn’t merit serious effort. I either have to assume you are really really green and haven’t done your homework or you are really really slimy and are just parroting talking points in order to get them coverage.
Which is it?
If the former, then I forgive you for sounding like every other broken record on this I’ve heard and you really need to go read up a bit somewhere other than WTFIUWT and Climate Depot. Hell, you’re learn more at Denial Depot than either of those places, but maybe go to Spencer Weart’s pages.
If the latter, well, you’re slimy and there’s just no excuse.
If it is such a naive or “slimy” question wouldn’t there be a simple rational stock explanation you’d programed to key F1 for all us slugs?
Are you saying you really don’t have a snappy rational answer to these, frankly deadly earnest issues? Just ad hom retorts?
The most fundamental prediction of the AGW hypothesis is that it MUST be much warmer today than at any time in the historical past. But there is robust evidence to contrary.
The second most profound implication of the AGW hypothesis is that the climate is changing far more rapidly today than at any time in the historical past. But that can be shown to be false.
What do you call a hypothesis whose fundamental implications and predictions don’t match the observed data?
What is the proper response of a rational and honest researchers when confronted with evidence that their hypothesis can not explain?
Sorry, Wes, I’ve used up all the the milk of human kindness flowing through my veins on you. There’s none left until I find something that will refill it. Until then, I’m sure if you were really interested in the issues and finding answers, you’d do what I have done — read the blogs, read the papers and do some ‘cogitatin so that at least, you’d come prepared.
“The most fundamental prediction of the AGW hypothesis is that it MUST be much warmer today than at any time in the historical past.”
This is a false claim. It’s as simple as that. Your failure to understand how false this claim is, show that you simply have no understanding of climate science. I already explained why it was false, and you ignored my response. Instead, you went after Susann. Conclusion? You are not interested in a rational and honest discussion.