Bishop Hill Show us your evidence
Jun 13, 2013 Climate: Parliament Climate: Statistics Climate: Surface Lord Donoughue's terrier-like pursuit of the observational evidence that we have experienced warming that is out of the ordinary continues unabated.
Lord Donoughue (Labour): To ask Her Majesty’s Government whether they have identified any observational evidence for statistically significant global warming, either natural or anthropogenic; and, if so, from what sources any such evidence originated.
Baroness Verma (Whip, House of Lords; Conservative): There is considerable observational evidence that the world has experienced statistically significant warming since the end of the 19th century. This is reported in Section 3.2 of the IPCC’s 4th Assessment Working Group I Report1.
We note that other statistical methodologies have been proposed and it is important that there is an open technical debate on their relevance to climate change analysis in the peer-reviewed literature.
In addition three-dimensional, physically-based climate models have been used to assess the climate’s natural internal variability and its responses to various external factors. Using standard scientific methods, the significance of observed global warming can be determined by testing detected temperature changes against the null hypothesis that they are entirely due to natural factors and have no anthropogenic contribution. The observed warming has been shown to be outside the bounds of natural climate system variability and is not consistent with model simulations that exclude anthropogenic factors, such as emissions of greenhouse gases. This inconsistency has been shown to be statistically significant1,2,3
I have offered the noble Lord a meeting with officials in three previous Written Answers (on: 13 February (Hansard, col. WA 158); 21 March (Hansard, col. WA 170) and 27 March (Hansard, col. WA 237-38) and I re-affirm this offer.
1 IPCC, 2007, Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.) Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
2 Stott, P. A. and Gillett, N. P. and Hegerl, G. C. and Karoly, D. J. and Stone, D. A. and Zhang, X. and Zwiers, F. Detection and attribution of climate change: a regional perspective Wiley Interdisciplinary Reviews: Climate Change, 1,2,192-211,2010.
3 Hegerl, G. and Zwiers, F. Use of models in detection and attribution of climate change. Wiley Interdisciplinary Reviews: Climate Change, 2 (4), 570-591, 2011.
Bishop Hill
Lord Monckton says that Santer's 17-year test has been met! (Link)
Reader Comments (67)
I put this in another thread, but it bears repeating here.
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EM - "They will also know why."
Please can you support this with a reference?
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"Sceptics point to the Medieval Warm period as being as warm as the present and say that Marcott et al is wrong when it shows the same warmth. Let's have some consistency here"
Complete rubbish! Entropic Man, we have had this discussion on other threads, and you know very well that the "sceptic" position is that the MWP was MUCH WARMER than current conditions. Start with the archeological evidence for dairy farming on Greenland and work from there....
You cannot simply flit from thread to thread, having failed in your arguments, and hope to start up the same conversation again, with the slate wiped clean.
Rhoda, Tom Bromige
You dont need proxies for the 20th century . We have a direct measurement record.
For the MWP there are no direct measurements. You have to depend on proxies, as Marcott et al does. As for the time period, Marcott et al used a 120 year base period. Since the MWP ran from before 280 AD into the 15th century, it would easily be detectable by their method, and was.
My problem is with people who say that the MWP was as warm as today while rejecting the paleoclimate data which confirms their statement. Without the proxies, how do they know? I know that it is human to hold two mutually contradictary opinions. at once, but it doesnt help your credibility in scientific debate.
For the modern data, remember that the NOAA usews 1500 Climate Reference weather stations plus ship, buoy and satellite data . Sample size for a years data, n, exceeds 7000 measurements and the sample would show a normal distribution. I suggest you look up mean, variance, standard deviation, normal distribution, 95% confidence limits, significance. This is bread and butter statistics for any scientist collecting numerical data.
Once you understand these terms, and how they relate, you will have a clearer idea why I look at some of the statistical discussion here with such a jaundiced eye.
I am disappointed that you ignore data that you do not believe in. Belief (or disbelief) is a very unscientific basis for analysing data.
Roger Longstaff
You never did get back to me with the numbers for the MWP Greenland temperatures, and your source.
And what was the minimum temperature for a working dairy farm?
Re: Greenland:
http://www.skepticalscience.com/medieval-warm-period.htm
Re: Dairy farming:
http://irishfarmerette.com/2012/11/06/autumn-dairy-farming/
First couple that google pulled up - Roger may have other sources.
"You never did get back to me with the numbers for the MWP Greenland temperatures, and your source."
You have a conveniently short memory - remember this?:
"EM, from your wiki reference: ".....during the so-called Medieval Warm Period, the vegetation there was very different from what it is today. Excavations have shown that the fjords at that time were surrounded by forests of 4-to 6-metre-tall birch trees and by hills covered with grass and willow brush."
I repeat my point: Greenland in the MWP must have been considerably warmer than current conditions, not colder by 0.5 degrees, as shown by Marcott et al. To me this invalidates Marcott (apart from the "trick" of splicing modern instrumental records).
Jun 5, 2013 at 9:11 AM | Roger Longstaff"
What is the point in debating with you, when you ssek to falsify the past?
Jun 14, 2013 at 12:52 AM | Entropic Man
Once you understand these terms, and how they relate, you will have a clearer idea why I look at some of the statistical discussion here with such a jaundiced eye.
I've just realized: you must be the real Billy Liar.
The past can be studued by using scientific methods such as ice core, sediment, pollen analysis, O^16/O^18 ratios and other proxies. These give data like your quote about woodlands. They also allow you to derive temperature data.
Note that birch survives under quite cold conditions. Birch forests are colonising thawing tundra permafrosts in Northern Canada with average annual temperatures below 4C, under conditions far to cold for dairy farming.
You, on the other hand, claim that the proxy data is all wrong and then give me vague comments about dairy farming with no numbers at all. When I ask for the minimum temperature for dairy farming you do not know, yet you claim it shows that temperatures were warmer than today.
This is becoming a mantra. Stop telling me I'm wrong, show me I'm wrong. Give me numbers and firm evidence, not this qualitative anecdotal waffle.
Billy Liar
The field of climate science is populated by individuals for whom lying has become an addiction, but who who are too stupid to lie their way out of a kindergarten.
Mike Hulme (UEA) received a lot of publicity for admitting on BBC radio 4 that climate science was a body of embarrassing nonsense. As a deeply committed environmentalist, his solution was as follows :-
"The idea of climate change should be seen as an intellectual resource around which our collective and personal identities and projects can form and take shape. We need to ask not what we can do for climate change, but to ask what climate change can do for us."
Hulme then goes on to suggest that all climate change arguments should include at least one of the following four "myths" (being a motivational story).
1. Lamenting Eden - To give the idea that the world was stable until man turned up. And we broke it.
2. Presaging apocalypses - Where you should use phrases like "impending disaster" and "tipping point". This is despite having the knowledge of such predictions (as Hulme states) but should because it "capitalizes on the human inbuilt fear of the future."
3. Reconstructing babel - Appealing to our fear of advancement and technology. As though anything modern is inherently bad.
4. Celebrating Jubilee - Balancing the cosmic unfairness of the world where well off inherently make this worse for the poor and the balance should be readdressed every 25 years.
In other words, to lie like professional con men.
The underlying premise here is that scientists are vastly more intelligent than simple mortals and can lie at will. They can't. Have you read political discussions at Realclimate ? They are supposed progressives with an extreme conservative, regressive agenda,. They are political morons of the first order.
What qualifies as an extreme weather event.So sunshine in summer and snow in winter.When it is out the ordinary,what qualifies as ordinary.
@Roger Lonstaff
Roger,
It doesn't invalidate Marcott. And Marcott did not splice a modern instrument record (although some reporters did later). The Marcott paper had a temporal resolution of about 300 years. This has the effect of smoothing out peaks and troughs in the temperature record, and so it cannot be compared directly with modern instrument data averaged on an annual basis. The strange uptick at the end of the Marcott series was caused by a mathematical artifact and has no significance whatsoever, as subsequently acknowledged by the authors. (Rather too quietly in light of the initial press reaction, in my opinion.)
EM, is it your assertion that it has never been warmer than it is now? I do not refer only to the MWP but also to the previous warm periods. I believe those periods give an indication of the span of natural variation. That was the basis of my earlier claim.
Marcott's problem was not the data, it was the presentation. Both in the late uptick and the excessive smoothing. There is a lot of data about the MWP outside of Marcott. Sometimes it's there, sometimes it's not, as in the hockey stick. Sometimes the exact timing of it does not match between datasets. However, if it was 'as warm' or warmer than now it still gives us input to a scaling of natural variation. There is no conflict here except with those who deny the MWP or emphasise a claimed lack of globality. It doesn't matter, it was even warmer before that.
I don't know whether anyone noticed, but the reference to the IPCC AR4 WG1 report leads to this (the only place where statistical significance is discussed):
For the statistically illiterate, this is the exact same statistical model applied by the UK Met Office in response to Lord Donoughue's early questions and which led to his questions about relative likelihood.
Although this is all very entertaining as a spectator sport, in agreement with previous commenters, I think that there is only one element in the answer which Lord Donoughue might find valuable to pursue, and that is the comment: "The observed warming has been shown to be outside the bounds of natural climate system variability". To support this, the UK Met Office has to reference paleoclimatology. It cannot use model studies to support this assertion. It would be interesting to see if they are prepared to reference reconstructions with known flaws, or if they decide to go with the less risky strategy of saying that the IPCC says so.
"You, on the other hand, claim that the proxy data is all wrong and then give me vague comments about dairy farming with no numbers at all. When I ask for the minimum temperature for dairy farming you do not know, yet you claim it shows that temperatures were warmer than today."
How much warmer? Ask a botanist. The point is that it was clearly warmer than today and that the evidence is based upon archeology and human records, not proxies, thus invalidating the MO statement "The observed warming has been shown to be outside the bounds of natural climate system variability"
A colder LIA and a warmer MWP (& RWP) are all the evidence necessary to falsify the MO thesis. A child of ten can understand that argument.
EM, you asked for references - try this:
http://www.odlt.org/dcd/docs/soon_bal_climate_res_paper.pdf
The conclusion? The 20th Century was not unusually warm or extreme, directly contradicting the MO thesis and with dozens of peer reviewed references. Enjoy.
Lord Donoughue is doing a public service by getting these essential references unambiguously on the public record. I hope he declines the offers of "meetings" and continues in this vein.
Jun 14, 2013 at 3:01 AM | eSmiff
Billy Liar was a fantasist (in Waterhouse's book).
EM -
Have you got a reference for this? I ask because the natural treeline (if there is no browsing by sheep and deer) for birch in the Scottish Highlands is about 2500-3000 feet which corresponds to an annual average temperature of about 4C. If there are birch in Canada which can colonise at -4C then I think the FC and other landowners would be planting trees to the summits of Nevis and the Monaruaidh. Unlikely.