"There were not enough Men present on the Earth 9000 years ago to create an 8C increase in temperature so something else caused it and we aren't sure what but orbital variations are a popular theory. The Earth has these temperate periods of 10-20 thousand years, roughly every hundred thousand years - and then they end. That was 8C. The AGW claimed here is about 1.5C, and it seems to have stopped for now."

No, it's still warming. And as for the cause of the Holocene optimum, it's known to be orbital and we know that's not what's causing the current warming.

"Warm, though? We can deal with warm. The Earth has been much warmer in the past and it didn't self destruct. Some people will have to move, but they won't have to run - the change happens very slowly."

Before it happened slowly. The current change is actually quite rapid. I think there have been similar situations when the climate changed very rapidly and the die-off was something over 90%. Personally, I don't think it'll get that bad, but with likely long-term drought in the internal regions of the continents, life could get very interesting.

"The amount of this warming is unprecedented."

This doesn't need to be true. I think it definitely has been warmer in the past, possibly very hot (but there was no life, so who cares?). And it could just be that the amount of warming isn't unprecedented yet. The current trend continues up and since there's no known mechanism for bringing it down in the near future, it seems we'll be getting a lot warmer.

"The warming will continue past the point where the earth's feedback mechanisms can correct it."

This, too, doesn't need to be true. All that needs to be true is that the earth's feedback systems are too slow to correct it. At some point, we will stop adding massive amounts of CO2 to the atmosphere. Either we voluntarily do so, or we run out of fossil fuels, or we all die - one of those will happen. Then the earth can take the excess CO2 out of the atmosphere. But the mechanisms that the earth uses to do this take thousands of years and we've released millions of years of stored carbon in just a few centuries. So it will take a while for the balance to be restored (unless we devise a way to speed it up).

"What is the optimum temperature (or range) of the Earth?"

I don't think this is important in the current debate. We know that humans have released large quantities of CO2 into the atmosphere which has upset the balance. We also know that CO2 causes warming. Both of these are facts known because they've been measured (ie, there's no modeling involved). Where modeling gets involved is saying what will happen as we warm up more. As far as I can tell, that's the only debatable part of this - how hot will it get and what will be the consequences of that.

Mostly because the medieval warming period seems to have only occurred in the northern hemisphere. There are indications that it did not occur in the southern hemisphere. I haven't seen any good studies that show that it was a global phenomenon. As such it's not as important to the global climate.

However, let's say that it did exist globally. Even studies that favor the idea of a global medieval warming period show that current temperatures are warmer than those during the medieval warming period. Additionally, it took over 100 years (~200 years according to Watts) for the medieval warm up while the current warming trend surpassed that in less than 50 years (with a huge jump in the 90s).

"There is also the part that arctic ice has actually been increasing over the past few years."

Actually, this hasn't happened. True, the sea ice extent has increased from a low in 2007, but overall it continues it's decline from 1970 or so. But sea ice volume has continued to decrease due to the loss of multi-year ice, so the overall amount of ice continues to decrease. Sea ice extent is a measure of how things are doing right now (ie, weather) while sea ice volume is a measure of how things are doing long term (ie, climate). I'm not convinced there's enough data to say convincingly that the ice will go away in the next few decades, but there's definitely enough data to say convincingly that arctic ice has not been increasing over the past few years.

Why can't they get the data by buying it from the various countries' Met offices? All the climate scientists can buy that data, what's prohibiting these others? Many of these other scientists get plenty of funding from the energy companies, so it's not like they couldn't afford it. If the Met offices won't sell the data to the other scientists, then the beef should be with the various Met offices. If these scientists don't like paying for the data, they should talk to their respective governments. Governments seem to want the Met offices to support themselves by selling this weather data and they're the ones that won't let it be released.

Or are you saying that any climate scientist needs to subsidize every other scientist that wants to use this data? I'm not in the climate field, but if anybody told me that I had to pay for other scientists to get computer time in order to check my work, I'd be plenty pissed.

The only other alternative would be that you'd prefer that this data just not be used. But that would hamstring science.

The fact is that at least a good number of anti-AGW scientists do have access to this data and they still haven't find anything profoundly wrong with the results from the mainstream climate scientists. And haven't for decades. This isn't to say they haven't done any good. It's healthy in science to have skeptics, as long as they are capable of understanding the science.

As the article you linked to says, this has already been accounted for and it accounts for something less than 18% of the greenhouse effect. It's well known how effective each greenhouse gas is - that's just everyday physics and has been tested in labs and known for decades. CH4 is a more powerful greenhouse gas than CO2, but there's much, much more CO2 in the atmosphere than CH4. So CO2 causes more warming than CH4. Now no one says that CH4 isn't a problem, it is. But CO2 is well known to be a bigger one.

Um, why don't you go to their website and download their data and models and do just that? Contrary to what you may have heard, they released all the data they were allowed to. There was data that was owned by various governments that it was illegal for them to release, but everything else was released. Sure, you won't understand it because you don't have the education, but when has that stopped you from commenting before? :)

You're exactly right except everything you just said was wrong :).

The globe is still warming and it's well known not to be caused by volcanism and solar activity because:
1. Volcanoes are known to release about 1% as much CO2 as humans release into the atmosphere. There are other things that volcanoes release, but those tend to cool things down, so they can't cause warming.
2. The amount of energy coming from the sun has been steady, or slightly decreasing, for the last 40 years. So that couldn't cause the warming.

Man, glad the climate scientists didn't do that.

"Nobody is taking a "scientific" approach to it, mostly because the results from the data aren't really reproducible. Again, this is because the data and the model are very obscure and complicated. There is also a lot of tweaking and processing going on with the data."

I don't think you know what's really going on. There are a number models and most of the scientists (at least claim to) understand them. However, they all pretty much agree, so it is all reproducible. And there isn't any tweaking other than adding the known physics. But that's how all sciences work (or are supposed to).

"If things are as bad as some people believe, why aren't they taking action? If every car, every airplane, every factory, every power plant is pushing things further and further into what was quoted recently as a 200 foot rise in sea level, why aren't the believers (and the scientists themselves) stopping every flight they can?"

So you've got scientists who, for the most part, just want to do the science. Let's say there are 5000 of them worldwide. And they're supposed to do, what? Bomb the airports and factories? Does this seem sensible? All they can do is release the facts as they know them to be and hope the populace and politicians can make the correct decisions. On the other side you have corporations who are making lots of money. Who do you think is going to win in this game?

Most of the thousands of climate researchers are out of the public eye and, guess what? They get the same answers as the results from researchers in the public eye. The amazing thing is that you can throw away all the data that came from the climategate researchers and it doesn't change things at all. It's also amazing that there have been lots of people trying to refute the climate change theories over the last 100 or 150 years and they've never been successful. And after reading all those climategate they haven't been able to find any evidence of the researchers trying to skew the data.

By the way, I know you changed your reference to IPCC later, but you're correct that the IPCC skewed the data that was presented. I know that at least in the data on the expected sea rise that they took more conservative values than are generally accepted, and then applied that a point before 2100 rather than take the rise all the way to 2100. They didn't want to be alarmist :).

I don't know. The USA (and a lot of other countries) might not be too happy since it means releasing the UK is saying it's OK for these scientists to release the USA's proprietary data. So I guess, you're right in that those jerks like the USA (and a lot of other countries) that wanted to profit from this data will get their comeuppance, but I wonder if we now need to increase taxes in order to pay for these services that used to make a profit. So that means that we all need to pay more money because of this.

I also wonder what it means for the university to release data that is illegal for them to release. I mean, on one side the court says they need to release it, but on the other side other courts say it's illegal to release it. Should be interesting in the UK for a while.

So lets look at those errors:
(1) Himalayan glaciers could be gone by 2030

Yes, that's the error. And it was corrected after the error was pointed out.

(2) there's been a rising cost of disasters due to more CO2

This is based on the story by Jonathan Leake, I'm guessing. The IPCC report said that one study indicated there was an increase in costs due to AGW while other studies did not detect a trend. So the IPCC report was balanced. Isn't that what people want? I haven't heard of a retraction by Leake yet.

(3) 40% of amazon forest could be destroyed by warming

This was based on research by Richard North and reported by Jonathan Leake. The research by North has been shown to be in error and several errors were pointed out to Leake prior to his publishing the story, but that didn't stop him. I haven't heard of a retraction as yet, but since you're repeating the claim, I'm guessing there hasn't been one.

(4) 55% of Holland is below sea level.

This was based on data provided by the Dutch government, so I'm not sure you can call this an IPCC error. However, it was corrected when the Dutch government changed their value. And it wasn't used to make any conclusions in the IPCC report, so if you want to call it an error, it was a trivial one.

So there you have it. One real error and one maybe error. And here's the thing: when the IPCC is found to be in error, they correct it. That's something I don't see from skeptics. Heck, just this week someone repeated the claim that Mars is warming and that's been debunked for I don't know how long. Or I'll hear that scientists have to be pro-AGW to get funding and that's well known not to be true. I would really like the skeptics to be better because I don't think I buy all the claims of AGW, but all the skeptics (at least the ones that get any publicity) seem to have difficulty with logic and math and science and ethics. There's certainly some of that on the pro-AGW side, but it seems that all the best scientists are pro-AGW and only the second or third tier will lean to anti-AGW. I don't know, maybe there are some real top notch skeptics out there, but I bet if there are, that they're being quiet because right now it's really embarrassing to be affiliated with the skeptics.

Umm, sure. But we're talking about a delta in the water vapor, but no decrease in the CO2 levels. Surely you can imagine a situation where a small decrease in water vapor is enough to reduce (but not eliminate) the temperature increases over the last decade. So an absolute comparison of greenhouse gas effects between CO2 and water vapor is irrelevant in this conversation.