Posts Tagged ‘John Christy’

John Christy, Richard McNider and Roy Spencer trying to overturn mainstream science by rewriting history and re-baselining graphs

February 22, 2014

Who are the Flat Earthers?

Before the advent of modern climatology, common wisdom had it that we tiny humans couldn’t possibly influence climate. Modern science shows we can. Yet John Christy and Richard McNider claim the exact opposite in a recent WSJ op-ed, in which they claim that their outdated views on climate somehow make them modern-day Galileo’s (or in their words: Why they are the ones declaring that the earth is round while the vast majority of the climate scientists persist in thinking the earth is flat). They couldn’t be more wrong.

Back then, scientific evidence slowly overturned the religious-cultural notion that the Earth was the centre of the universe. This resulted in a scientific consensus that the Earth revolves around the sun. More recently scientific evidence has started overturning the notion that humans can’t possibly influence something as gigantic as the Earth’s climate. This too has resulted in a scientific consensus  (though a public consensus is still lagging behind). In both cases, the pre-scientific notion was mostly culture-based, as opposed to being evidence-based.

As Jeff Nesbit tweeted: “Being the last scientist to accept established climate science doesn’t make you Galileo.” Quite the opposite indeed.

The Galileo-complex also suggests a rather simplistic view of how science progresses. Rather than a lone skeptic overthrowing a scientific (rather than a cultural) consensus, scientific progress is a usually a gradual process. New evidence has to be reconciled with the existing mountain of evidence; it doesn’t simply replace it. Observing a bird in the air doesn’t disprove gravity. “Skeptics” and their supporters often bring up Galileo as an example of that the scientific consensus can also be wrong, and has been wrong in the past. True enough, though as Carl Sagan said: “they laughed at Galileo, but they also laughed at Bozo the clown”.

Hot spot

Besides their entirely misplaced Galileo-framing, Christy and McNider also make a range of unsupported and/or incorrect statements. One argument deals with the so-called tropical tropospheric hot spot. This refers to the expected stronger warming of the tropical troposphere as compared to the surface. This “hot spot” is independent of the cause of the warming. But what do Christy and McNider write in the WSJ:

(the warming of the deep atmosphere is) the fundamental sign of carbon-dioxide-caused climate change, which is supposedly behind these natural phenomena

But hang on, didn’t Christy admit to the basic science that this hot spot is not specific to a greenhouse effect? Yes, he did (at the ClimateDialogue discussion in which he participated):

“Yes, the hot spot is expected via the traditional view that the lapse rate feedback operates on both short and long time scales. (…) it [the hot spot] is broader than just the enhanced greenhouse effect because any thermal forcing should elicit a response such as the “expected” hot spot.”

So why is he claiming something in the WSJ that he knows to be untrue?

Model-observation comparison

It almost goes without saying that any climate model-observation mismatch can have multiple (non-exclusive) causes (as succinctly summarized at RC):

  1. The observations are in error
  2. The models are in error
  3. The comparison is flawed

But rather than doing a careful analysis of various potential explanations, McNider and Christy, as well as their colleague Roy Spencer, prefer to draw far reaching conclusions based on a particularly flawed comparison: They shift the modelled temperature anomaly upwards to increase the discrepancy with observations by around 50%. Using this tactic, Roy Spencer showed the following figure on his blog recently:

Roy Spencer misleading figure - CMIP5-90-models-global-Tsfc-vs-obs-thru-2013

So what did he do? Jos Hagelaars tried to reproduce the different steps involved. A comparison of annual data, using a 1986-2005 baseline, would look as follows:

Jos Hagelaars - comparison_cmip5_hadcrut4_uah

Spencer used a 5 year running mean instead of annual values, which would (should) look as follows:

Jos Hagelaars - spencers-graph-reconstructed-part-1

The next step is re-baselining the figure to maximize the visual appearance of a discrepancy: Let’s baseline everything to the 1979-1983 average (way too short of a period and chosen very tactically it seems):

Jos Hagelaars - spencers-graph-reconstructed-part-2

Which looks surprisingly similar to Spencer’s trickery-graph. But critiquing Roy Spencer comes at a risk: He may call you a “global warming Nazi”. Those nasty CO2 molecules, that’ll teach them!

Many thanks to Jos Hagelaars for the data analysis and figures.

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Tropospheric hot spot

August 19, 2013

The current topic under discussion at ClimateDialogue is the tropospheric hot spot: Is it there, and if not, so what? Invited discussant are Steven Sherwood of the University of New South Wales in Sydney, Carl Mears of Remote Sensing Systems (working on the RSS satellite product) and John Christy of the University of Alabama in Huntsville (working on the UAH satellite product).

I’ll provide a short overview here (loosely based on the intro over at CD), interspersed with my own and other people’s commentary.

Based on theoretical considerations and simulations with General Circulation Models (GCMs), it is expected that any warming at the surface will be amplified in the upper troposphere. The reason for this is as follows: More warming at the surface means more evaporation and more convection. Higher in the troposphere the (extra) water vapour condenses and heat is released. Calculations with GCMs show that the lower troposphere warms about 1.2 times faster than the surface. For the tropics, where most of the moist is, the amplification is larger, about 1.4.

This means that, contrary to what some people claim, the hot spot is not specific to the enhanced greenhouse effect: Any surface warming (or cooling) would be expected to be magnified higher aloft, at least in the tropics. Lindzen says it as follows:

We know that the models are correct in this respect since the hot spot is simply a consequence of the fact that tropical temperatures approximately follow what is known as the moist adiabat. This is simply a consequence of the dominant role of moist convection in the tropics.

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