The 10 worst warming predictions

New Year is the time to re-evaluate, and model predictions are no exception. Andrew Bolt has a list of how 10 climate predictions fared in 2008. Too triumphal for my taste, but worth a read, even if for the last line.

Those, then, are the top 10 dud predictions of that hooting, screaming and screeching tribe of warming alarmists. Look and laugh.

And dare to believe the world is bright and reason may yet triumph.

New Forum Facility Added

A forum has been added using the software phpBB (link on menu bar above). This is a message board/community forum for landshape related issues.

We are at the stage of needing this, as there are a number of interesting and lengthy discussions which are hard to do justice to in this format. As well, a number of knowledgeable contributors need a forum for posting dedicated threads.

Currently anyone can add new forums under the categories:

Modeling and Statistics (Climate Change)
Forum (Journal Club)
Software (Pollnet – the polls software that drives the polls you see above)
Administration (Technical Issues)

I welcome anybody to try this out by adding forums or posting under these forums.

Carbon Credit Mission Impossible

Yesterday, the UN suspended a firm responsible for 50% of carbon-offset certifications, after a spot check carried out in early November at the firm’s headquarters revealed serious flaws in project management.

As international climate talks began last week in Poland, the United Nations (UN) suspended the work of the main company that validates carbon-offset projects in developing countries, sending shockwaves through the emissions-trading business. At its meeting on 28 November in PoznaÅ„, the CDM’s executive board temporarily withdrew Det Norske Veritas’s accreditation after a spot check carried out in early November at the firm’s headquarters revealed serious flaws in project management. Critics of CDM have long warned of possible conflicts of interest, pointing out that private companies such as Det Norske Veritas have a business interest in not deterring customers by being too critical about proposed projects.

Carbon Credit prices have fallen dramatically.

MUMBAI: Prices of carbon credits have fallen to euro 14 per tonne from a peak of euro 20 two months ago – a level, which experts feel, is unlikely to be regained in the short term. The price has come down on the back of a fall in crude prices. CER rates and crude prices are inextricably linked. Crude prices on the New York Mercantile Exchange are ruling below $47 per barrel. Crude had touched a record high of $147 per barrel on July 11 this year, after which it has been declining.

Skeptics have had a consistent position with regard to global warming: actions to reduce GHG emissions would not be worth the investment. The position was strongly vindicated by the original analysis of Ross Garnaut where Terry McCrain reports on page 21 of the Target and Trajectories supplement that:

“The optimal level of Australian mitigation effort — the level that maximized incomes and wealth of Australians — is easily calculated. It would be zero.”

These calculations are described in more detail in Andrew Bolts article: “Garnaut Turns Up Heat on Rudd“. The results of his simulations show that reducing emission by 25% would reduce GDP by 1.6%, while doing nothing would reduce GDP by 0.7%.

KEVIN Rudd’s global warming guru has finally – and reluctantly – exposed the con. Ignore everything the Government has told you. The truth, conceded by Professor Ross Garnaut last week, is that it really is cheaper for Australians to do nothing about global warming.

Assumptions for linear regression

One of the main assumptions of linear regression is, ahem, linearity. Here is an example drawn from dendroclimatology, the reconstruction of past climates using tree rings, of the trouble one can get into by blindly assuming linearity. This subject was dealt with some time ago at ClimateAudit Upside-Down Quadratic Proxy Response.

From the Summary of chapter 9 of my book, niche-modeling-chap-9

9.2 Summary
These results demonstrate that procedures with linear assumptions are unreliable when applied to the non-linear responses of niche models. Reliability of reconstruction of past climates depends, at minimum, on the correct specification of a model of response that holds over the whole range of the proxy, not just the calibration period. Use of a linear model of non-linear response can cause apparent growth decline with higher temperatures, signal degradation with latitudinal variation, temporal shifts in peaks, period doubling, and depressed long time-scale amplitude.

Niche Modeling: Predictions from Statistical Distributions. Chapman & Hall/CRC, Boca Raton, FL., 2007.

I notice Craig Loehle converged on similar results in post about a publication on the Divergence Problem. In the abstract Craig finds a similar quantitative depression in the range of signal recovered.

If trees show a nonlinear growth response, the result is to potentially truncate any historical temperatures higher than those in the calibration period, as well as to reduce the mean and range of reconstructed values compared to actual.

By far the most interesting result I find is the introduction of ‘doubling’ from assuming a linear response of a non-linear variable. This is illustrated by Craig’s figure here:

Because over the course of one climate cycle, the tree passes through two optimal growth periods, the tree is, in electrical terms, a frequency doubler. This would create enormous difficulties in trying to detect major features such as Medieval Warm Periods and Little Ice Ages from such a responder.

But the problems do not end there. According to the latitudinal (or attitudinal) location of the tree, relative to its optimal growth zone, the location of the doubled peaks is shifted temporally. This shifting of the peaks is illustrated in the figure below, taken from my chapter.

If one then imposes two non-linear responses, such as temperature and rainfall, the response becomes even more choppy, as shown in another graphic from the chapter.

The recovery of a climate signal in the face of nonlinearity of response is fraught with difficulties. When the fundamental growth response of a trees, and all living things actually, is known to be a non-linear niche-like response, there is more onus on modelers to prove their methods are adequate.

While not unaware of the problem, most often in climate (and ecological) science, risky statistical prediction methods are used with inadequate validation, or like the drought modeling efforts by CSIRO here, results from GCMs are used with no attempt to demonstrate they are ‘fit-for-purpose’ at all. Rob Wilson argues at ClimatAudit that while linear modelling of tree-growth relationships is not ideal, the field is ripe for some fancy non-linear modelling. Given the range of exotic features introduced by non-linearities, as I showed above, I would argue that fancy non-linear modeling would probably lead more surely to self deception, and a better path is robust validation.