It was a link to MIT website where there is a webcast on climate uncertainties by Pro AGW scientist Prof Ronald Prinn.

Just watched it. It is a very well presented and (in my opinion) a balanced view of the science.

I will recommend it in future.

Can't see why Channel4 would want to delete your post, there is no copyright or legal issue that I can see. But they do seem to be a bit trigger happy.



MIT Joint Program on the Science and Policy of Global Change:

http://web.mit.edu/globalchange/www/

quote:

Originally posted by JL(SFC58,AFCB):
John M

I'm afraid I can't follow what your point is - except perhaps that you've found snow at the end of March.

Are you saying the Skeptics are unable to use the data contained in articles by the AGW-ers? If that be the case, then the Skeptics are unable to point out any contradictions they find in the AGW theories.

The points are:
1)
a) WIYM is wrong when he says the "AGW lobby" thinks there are no effects from sulfate aerosols, and the article he cited to show contradictions with the "AGW lobby" is written by a couple of the strongest AGW-supporters.

b) WIYM appears not to understand even a relatively *simple* article in this field, which doesn't encourage one to bother posting pointers or arguing any more. I've had reasonable discussions with legitimate sceptics who can at least read such articles.

c) And in any case, I gave him a pointer to the sort of peer-reviewed article he'd then asked for 9as far as I could tell), but he doesn't seem to have looked at that:
The effect of stabilizing atmospheric carbon dioxide concentrations on global and regional climate change
Geophysical Research Letters, Volume 27, Issue 18, p. 2977-2980.
Here’s a URL for an abstract: http://adsabs.harvard.edu/abs/2000GeoRL..27.2977M

which is one of many that analyze the likely effects of stabilizing CO2 at various levels, in this case 550 and 750ppm.

I haven't heard of any serious scientist saying they think we can stabilize it at the current 380ppm any time soon, although some think it may get back down there in hundreds of years, after the bulk of the oil&gas (and much of the coal) is used up. After all, based on the last couple previous interglacials, one would expect the CO2 to be around 240ppm now, not 280ppm. Once again, anyone who actually wants to learn about all this should read Ruddiman's book. It is way too late to stabilize at 380ppm: the article cited by WIYM shows that even serious acid rain isn't likely to do more than cool a few areas for a few decades.

In the long-term of course, assuming humanity survives the period when it gets uncomfortably hot, hopefully, technology will get good enough to do large-scale geo-engineering to keep the temperature from going back down to fast, given that having kilometers of ice over Toronto and Stockholm might be deemed unpleasant.

2) It is perfectly fine for sceptics to use data contained in articles by scientists who support AGW. What is silly is to claim that an article (by two of the chief AGWers), disproves what AGWers say. Again, when I asked for a peer-reviewed article, in a serious journal, by a serious author, that was sceptical of AGW, I was expecting to see metnioned some article by Lindzen or Baliunas or Michaels, where WIYM might not have tracked rebuttals, but I was truly astonished to see the article cited.

3) Regarding snow in March, indeed that is true, and we live near San Francisco, about 5 hours drive from Lake Tahoe ski resorts. We were skiing with friends who own places in Wyoming and Utah, also fine ski places.
When I posted that, I wasn't in any of those places, I was in Canada, because unlike those other 3 places, there is still pretty good snow, just like I remember from 20+ years ago in California.

Now, I do NOT ascribe any given year's conditions to AGW, as there is always a lot of variability, but California tracks snow and water fairly carefully:

The Sierra Nevada Snowpack: Do the Snow Course Data Show Historical Trends?
Among the postulated consequences of global warming, the hypothesis that the Sierra Nevada snowpack may decline is worrisome because of the dependence of the California economy on snowmelt runoff. Some Sierra Nevada snow courses have data records extending back to 1910, and about 100 of the courses have more than 70 years of data. A simplistic analysis shows little other than the obvious interannual variability, but a closer look reveals a declining April snowpack at the lower elevations, especially in the southern parts of the range. The low-elevation deficit is apparently not compensated by more snow at higher elevations.
http://adsabs.harvard.edu/abs/2004AGUFM.C31A0275D

If you go there and click on ("Find similar abstracts") you will find plenty of studies on snowpack effects in the West of the US.

Having studied climate change science very carefully (and very sceptically) during 2002-2003, including joing the AGU for a while, and having kept up with developments since then, we bought ski condo in 2005 ...
in Canada, a lot safer if you actually like consistent snow.

Now, it really is time to be back to real work.

Hey John M, I suggest that you watch the webcast, the link of which given by Robbie Writer above, that points to the uncertainties of climate science forecast. Poignantly, Prof Ronald Prinn says it is 'arrogant' to try and predict climate change, given the huge uncertainties in aerosol science, ocean science and cloud science. And Prof Prinn is definitely a pro AGW scientist.

It appears to me know that it is you who do not understand the uncertainties which the scientists themselves are remarably aware of

WIYM,

The webcast is about the MIT's prediction program.

He jokes about the MIT being "arrogant" to create such a complex modeling system but that is a joke.

He shows in the webcast how the uncertainties can be "constrained" by testing models from historical dates and ensuring they match the data we already have and thus enabling a higher degree of confidence in the models.

I think the statement points to the huge uncertainties involved in predicting climate change. The models are just that models. Even going by the projections of a pro AGW scientist, we have better probability of no climate change than a higher global temperature, in case we do nothing. And remember these are only 'scenarios' we are talking about.

another poignant statement from the webcast. Some one from the audience asks -can't the effect of rising aerosols cancel out the CO2 effect? Prof Prinn does not rule of this possibility but says future clean coal tech has to be considered, but questions whether we should then pursue clean technologies adding that this is just another example of the dilemma that is faced in making policies on climate science

Hey, I've had my post to the link removed too! I wonder what the problem is?

quote:

Originally posted by What's in your mind:
I think the statement points to the huge uncertainties involved in predicting climate change. The models are just that models. Even going by the projections of a pro AGW scientist, we have better probability of no climate change than a higher global temperature, in case we do nothing. And remember these are only 'scenarios' we are talking about.

I think this discussion with Prof Prinn proves my point:

http://network.nature.com/boston/news/articles/2007/02/...-scientists-to-agree

Does the new study [IPCC 4th assessment] address uncertainty more clearly?

Yes, and I’m delighted that the leadership took that approach–it states the likelihood that changes will lie within specific ranges, as best as we can project right now. The numbers and ranges in this report will be debated, and they will be refined in the next assessment, but that’s much better than having no ranges attached to the estimates. It’s a very big step forward.

Exactly!

The abstract you quoted relates to an article in Science, 20th July 2001.

The article I quoted is from nature network, 14th February 2007. In this article, Prof Ron Prinn states that his concerns in 2001 over the unaddressed uncertainties in the IPCC 3rd assessment have been addressed in the 2007 IPCC 4th assessment, by providing a set of ranges of outcomes which address the uncertainties.

Yup but they still use expert judgement for making critical claims. Do you have any indication that the process of arriving at expert judgment has change from the 3rd to the 4th assesment?

As far as I can see expert judgment is used.

The 2001 abstract you've quoted states "...and if expert judgment is used, a specific list of the experts consulted should be included."

So the important thing is that the IPCC publish the list of experts.

Yes. We do not have the list of experts in the summary. But it is important to note that the expert judgment is a subjective opinion and the objective confidence levels do not matter here

quote:

As for the aerosols, Prof Prinn didn't really have the opportunity to answer but as far as I understand, increasing aerosols which would reduce temperature, would also increase global dimming, which has been attributed with the extreme droughts in Africa in the 1980s. If China increased aerosols to counter global warming, it could cause severe crop failures in South Asia, causing mass starvation

How can a presenter not have an opportunity to answer back? you guys are very funny. Why mention about mass starvation? you don't know that, do you? The point is about uncertainty, and yes, watch the webcast would be my advise too.

He didn't have time to answer all questions fully. It was an hour long presentation, he had to hurry his presentation towards the end. Have you never been to a lecture? Booked rooms?

The whole point about the lecture is a model can be tested against known data, thus constraining the uncertainties into a range of possibilities.

The IPCC 4th assessment can predict with confidence within a range.

So if an expert judgment is used in the model, the model is tested against historical data and if the model does not match the historical data then naturally it is rejected.

If a model is tested against historical data and it produces the same results as has actually happened, then it is likely to be able to predict future climate changes.

There is a theory that global dimming caused by European pollution caused the decade of droughts in Africa. We know for sure the droughts caused mass starvation in the 80s.

So I said about Chinese pollution "it could cause severe crop failures in South Asia, causing mass starvation". Notice the word "could"!

It IS funny to see you defend something when there is nothing to defend in the first place.

As mentioned before by jj102, I think, who was at the IPCC summary report release at Royal Society, the expert judgement IS subjective opinion that means they are subject to change if a different set of authors are there in place of the current one

The webcast of Ronald Prinn shows that the scientists knows remarkably little about the underlying science of how the various variables interact each other in a non linear fashion. As they don't know these, they are trying to ground truth the model by putting the constraints of observable data, but that does not take away the fact that they know little of the underlying science itself. How well they are doing this 'ground truthing' I don't know. If you ask Richard Lindzen he will probably say not very well.

It is interesting to note that the AGW proposition is usually forwarded accompanied by a doom and gloom scenario. I wonder why? We can see how we can have a doom and gloom scenario WITHOUT man made CO2 and how mass starvation can happen if we have carbon trading imposed on developing nations. Let's talk about uncertainty and let's leave these flights of fancy for some other threads

It is interesting to note how Prof Prinn readily concedes the problem with the so called 'hockey stick' graph. He also does not deny the MWP, saying quite emphatically that he can only confirm that global temeperature witnessed recently is the highest in 1200 years leaving the MWP outside the claim

The peak of the MWP was between 1000 and 1100, less than 1000 years ago.

I suggest you see the webcast, where the presenter is an MIT scientist and not a virtual character

Don't have time to watch TV in work.

Does he say that there is a warm period more than 1200 years ago, then?

Well you can watch it in your computer if you have real player. You cannot watch it in TV anyway. And yes he says there is a possibility of global temp being higher in the MWP

quote:

It is interesting to note that the AGW proposition is usually forwarded accompanied by a doom and gloom scenario. I wonder why?

I was pointing out an argument against using aerosols to reduce temperature, because the effects of global dimming could also be severe.

I doubt anybody would argue the 80's droughts and subsequent mass starvation wasn't a catastrophe.

If the theory that links global dimming with these droughts are proven then global dimming **could** (now pay attention here WIYM - notice the word "could") be catastrophic in South East Asia too.

It is not about doom and gloom, I am pointing out a possibility, which is in a response to your point about aerosols.

WIYM,
Since you are a fan of Prof Ron Prinn, will you be looking forward to reading the IPCC forth assessment in the knowledge that the concerns Ron Prinn have been addressed:

Does the new study address uncertainty more clearly?

"Yes, and I’m delighted that the leadership took that approach–it states the likelihood that changes will lie within specific ranges, as best as we can project right now. The numbers and ranges in this report will be debated, and they will be refined in the next assessment, but that’s much better than having no ranges attached to the estimates. It’s a very big step forward."

It is not a question of 'using' aerosols to cool temperature. Aerosol emission is set to rise as acknowledged by some AGW scientists themselves, the question that Prinn addresses is whether we should push through policy that forces firms to adopt clean technologies and he pointed to the dilemma of such a policy decision. Now I wonder if a MIT scientist can see the dilemma why you cannot?