The European Warm Period ...

or better, the European Climate Optimum, was a period between 1000 and 1300 AD during which the climate in Europe was very warm compared to the immediately previous and following times. Often in the literature this is referred to as the Medieval Warm Period. While medieval is a term that only refers to a period of european history, those who seek to minimize the effects of humans on current climate often ignore the local nature of the warming in the European Climate Optimum to argue that it shows that current warming is not anomolous.

In the period 900 - 1400 AD, warming inferred from paleoclimate and historical records in other regions of the globe were not synchronous with the European warm period. The IPCC Third Assesment Report concluded that

Thus current evidence does not support globally synchronous periods of anomalous cold or warmth over this timeframe, and the conventional terms of “Little Ice Age” and “Medieval Warm Period” appear to have limited utility in describing trends in hemispheric or global mean temperature changes in past centuries.

Use of the preferred term "European Climate Optimum" clearly establishes the locality of the phenomenon as well as implying that because current warming exceeds that seen in the early parts of the last millennium, we have already gone beyond the optimum.

Ms. Rabett has grabbed the keys.....

and forced Eli to vacate. Back Aug 1.

How denialists argue

 After a similar post at Simply Left Behind (OK, a straight rip off but an object lesson)


Scientist: Carbon dioxide concentrations have increased sharply in recent times.

Denialist: No, they have not.

Scientist: Yes, it has, we have really good measurements since 1958 at Mauna Loa which show the CO2 mixing ration increasing from 315 ppm to 380 ppm. That is a huge increase in a short time.

Denialist: What about Samoa? What about that Samoa, huh? Or the South Pole. You’re saying those don’t count?

Scientist: We have measurements from those places too

Denialist: There is still no proper record of the carbon dioxide concentrations over industrial regions, or over forests and other cultivated regions.

Scientist: Well there are some measurements from industrial areas, forests and other cultivated regions but they are not for as long as the Mauna Loa record, and the noise in the data is higher. The concentrations of CO2 are pretty much the same around the world because the gas is well mixed into the atmosphere, so we don't have to measure everywhere. There are some differences between the north and the south hemisphere and near roads and factories, etc., but the concentrations have been rising everywhere

Denialist: Oh, so the people there don’t count? They’re not good enough, huh? I thought you scientists wanted measure the increase in CO2 everywhere.

Scientist: No, carbon dioxide is well mixed, .....

Denialist: You’re really something, you know that? You scientists are always going on about how all of us who don't believe in global warming are racists, how we don’t care about anybody but people who look like us. But you don’t even want to measure the CO2 that the Africans or the Asians are exposed to.

Scientist: First of all, I never said all denialists are racists.

Denialist: Yes, you did.

Scientist: No, I didn’t.

Denialist: Al Gore says it.

Scientist: I’ve never heard him say that.

Denialist: Yes, he does! He most definitely does!

Scientist: Look, I don’t know what he says. That’s beside the point. And the people in Africa “count,” whatever that means. I don’t even know who lives in Africa; I don’t know the first thing about Africa. I’m just saying the CO2 concentration in Africa is about the same as it is everywhere else. CO2 is well mixed.

Denialist: What about Puerto Rico?

Scientist: What?

Denialist: What about Puerto Rico, huh? You love all those Mexicans coming across the border stealing our jobs ­ and emitting CO2 from their old, smoky cars, you must LOVE Puerto Rico, right?

Scientist: I’ve never been to Puerto Rico.

Denialist: Well, I have, and those kind of people would be pretty offended to hear scietists like you saying they emit too much CO2!

Scientist: I didn’t say that!

Denialist: You said they didn’t count!

Scientist: I didn’t say that either! No, wait, just wait… (takes deep breath). I only said the amount of CO2 in the air has increased a lot. I'll go further, a lot of that comes from burning fossil fuel and a disproportionate share of the emissions comes from the US.

Denialist: How dare you accuse Puerto Ricans of emitting too much CO2.

Scientist: Well, Puerto Rico emits a lot less CO2 per capita than in the US mainland but undoubtedly there are improvements that can be made there too.

Denialist: How do you know that? I’ve been there ­ you haven’t!

Scientist: All right, OK, fine, whatever. But the USA emits an awful lot of CO2.

Denialist: Well, I say Puerto Rico counts.

Scientist: Fine, but as far as CO2 emissions go it is not nearly as important as the fifty states.

Denialist: Well, that’s YOUR opinion.

Scientist: It’s not my opinion ­ it’s a fact.

Denialist: Says you!

Scientist: No, not just “says me.” It’s a fact. Look it up.

Denialist: I don’t have time.

Scientist: You don’t have time to find out how much CO2 the US emits?

Denialist: Listen, you may have time to sit around all day surfing on your "science" websites, downloading Al Gore, but I’ve got things to do.

Scientist: Like reading about how much CO2 is emitted in Guam and by Mexicans in Puerto Rico?

Denialist: See, that’s why you guys always lose. I’m trying to have a nice conversation, and you just keep up with the insults!

Scientist: Listen, I didn’t mean to insult you.

Denialist: Oh, yes you did!

Scientist: No, look, I’m sorry, OK? I didn’t mean to insult you. Honestly. It’s just that… well, the USA emits too much CO2. If we continue to do so there can be very dangerous consequences. That’s a fact. And I’m just trying to state a fact, and you’re getting very defensive, and…

Denialist: Oh, so now I’m defensive.

Scientist: Well…

Denialist: You just said you weren’t going to insult me!

Scientist: Look, I’m just trying to say the USA emits too much CO2!

Denialist: According to YOUR sources!

Scientist: MY sources?! What are you talking about? Look it up!

Denialist: I told you, I don’t have time to spend all day cruising the internet, looking up science questions! Maybe if you were busier at your job, trying to live the American Dream, you wouldn’t have time for all this hate!

Scientist: I work hard at my job!

Denialist: Then why are you spending all day downloading Al Gore?

Scientist: I don’t spend all day downloading Al Gore! I don’t even know what you mean by that! All I’m saying is that the USA emits a lot of CO2!

Denialist: Again, according to YOU!

Scientist: Not just me! Here, here’s the IPCC Third Assessment Report. Look it up!

Denialist: Oh, sure, the IPCC! Yeah, like I’m going to believe the IPCC! It's just another UN organization trying to take over the USA.

Scientist: What?

Denialist: Come on, it’s a communist front!

Scientist: (Long, teeth-gnashing pause) Look, just look up “United States of America CO2 emissions” in the Wikipedia. Ten bucks it says, “the USA has the highest CO2 emissions and the highest per capita emissions by far.”

Denialist: Ten bucks, huh?

Scientist: Yeah, ten bucks. (pause) Wait, that’s the “G” section.

Denialist: I know.

Scientist: You need to look under “U” for “United States.”

Denialist: I’m not looking for “United States.” I’m looking for “Gore, Al.”

Scientist: What?!

Denialist: And when I find a big glowing article about him, you’re going to owe me ten bucks!

Scientist: Why would I owe you ten bucks?!

Denialist: You bet me ten bucks that the Wikipedia isn't liberal.

Scientist: No I didn’t!

Denialist: Yes, you did! You bet me ten bucks that I couldn’t find a liberal article in the Wikipedia. So when I find Al Gore’s picture, you owe me ten bucks!

Scientist: Oh, my lord…

Denialist: AHA!

Scientist: Listen, you idiot, just because you found Al Gore’s picture in the Wikipedia doesn’t mean that I owe you ten bucks! It doesn’t mean the Wikipedia is a socialist encyclopedia! And it certainly doesn’t mean the USA doesn’t emit the most CO2!!

Denialist: Oh, no? Look at this!

Scientist: (pause) “China”?

Denialist: Bingo!

Scientist: What the hell does China have to do with anything?

Denialist: The PEOPLE'S REPUBLIC of China!

Scientist: So?

Denialist: So you said the US emits too much CO2, what about China, you gonna give those communists a free ride!

Scientist: Oh, no…

Denialist: You ADMITTED China was a communist country! Admit it, you said it!

Scientist: Oh, man…

Denialist: So if China is a communist country, and the UN is run by China, then they BOTH must be socialist! HA!

Scientist: OK, look…

(pause)

Denialist: That’s it, cut and run!

(long pause)

Denialist: Why do you hate America?

What if global warming were natural? ...

Is a question that David Appell put, and that was picked up by William at Stoat.

There are two simple rules that govern such questions. The first is that it is easy to construct a question that has no meaningful answer. While the concept of global warming is reasonably clear, natural is so vague that it makes the question "What if global warming were natural" fodder for stupid answers, which appear to be in plentiful supply.

The second rule is that to ask a meaningful question requires knowing a lot about the answer. So let us proceed to break down the situation.

There is one simple answer which is that if there are other factors which overwhelm what people are doing to the climate system, then our understanding of the effect of greenhouse gases, global albedo and many other things is not just off, but drastically wrong. This is quite the claim and there better be a strong proof before anyone asserts any such thing without expecting to be laughed out of the house.

The next step is to differentiate between the various possible things that could lead to global warming and are not controlled by man. For example:

Can global warming be attributed to changes in solar irradiance? (Answer: some part can, but the measured changes in solar irradiance are not sufficient, especially over the last thirty years when direct satellite measurements of solar irradiance are available).

Well then, are there indirect mechanisms which could amplify the observed change in solar irradiance? (Answer some have been proposed, but they have not held up. This includes various cosmic ray dreams)

We can also rule out effects due to orbital changes over the last 150 years, or we have to show that our knowlege of the orbit of the earth is zilch.

OK, then what is left are processes inherent to the Earth system itself. See the simple answer above.

UPDATE: The last comment at Quark Soup pretty much nails it, but I had this up already

An Inconvenient Truth.....

the book, hit #2 on the NY Times Paperback non-fiction list. So much for unpopular.