"Climate modelers have been "cheating" for so long it's almost become respectable"

The above quote from a Warmist modeller writing in "Science" magazine in 1997 gets a run every now and again so I thought I might say a little bit about it.

Warmists are of course very defensive about it, claiming that the quote is taken out of context. And they are right about that, though not perhaps in the way they would want. So let me start with an extended quote from the original:
Climate modelers have been "cheating" for so long it's almost become respectable. The problem has been that no computer model could reliably simulate the present climate. Even the best simulations of the behavior of the atmosphere, ocean, sea ice, and land surface drift off into a climate quite unlike today's as they run for centuries. So climate modelers have gotten in the habit of fiddling with fudge factors, so-called "flux adjustments," until the model gets it right.

No one liked this practice (Science, 9 September 1994, p. 1528). "If you can't simulate the present without arbitrary adjustments, you have to worry," says meteorologist and modeler David Randall of Colorado State University (CSU) in Fort Collins. But now there's a promising alternative. Thirty researchers at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, have developed the first complete model that can simulate the present climate as well as other models do, but without flux adjustments. The new NCAR model, says Randall, "is an important step toward removing some of the uneasiness people have about trusting these models to make predictions of future climate" (see main text).

The NCAR modelers built a host of refinements into their new Climate System Model (CSM). But the key development, says CSM co-chair Byron Boville, was finding a better way to incorporate the effects of ocean eddies, swirling pools of water up to a couple of hundred kilometers across that spin off strong currents. Climate researchers have long known that the eddies, like atmospheric storms, help shape climate by moving heat around the planet. But modelers have had a tough time incorporating them into their simulations because they are too small to show up on the current models' coarse geographic grid. The CSM doesn't have a finer mesh, but it does include a new "parameterization" that passes the effects of these unseen eddies onto larger model scales, using a more realistic means of mixing heat through the ocean than any earlier model did, says Boville.

Even when run for 300 model "years," the CSM doesn't drift away from a reasonably realistic climate, says NCAR's Climate and Global Dynamics director Maurice Blackmon. "Being able to do this without flux corrections gives you more credibility," he says. "For better or worse, we're not biasing the results as was necessary before."

The quote is from: "Climate Change: Model Gets It Right--Without Fudge Factors" by Richard A. Kerr.

So it sounds like a good bit of Warmism at first. It offers an alternative to fudging that works. But let's look closer. The first clue is in the journal abstract itsef. We read there: "The first results from this model imply that future greenhouse warming may be milder than some other models have suggested--and may take decades to reveal itself"

Not so rosy! Removing the fudges also removes the urgency! But it gets worse. In a commentary on the Kerr article we read:
The NCAR model produces a modest warming of about 1.8oC over 100 years. But it has the wrong greenhouse effect! The model effectively increases the CO2 greenhouse change by 1 percent per year, but everyone knows that the actual increase is 0.7 percent. Our figure shows the original result along with an adjustment for reality.

Figure 1. TOP: Temperatures predicted by Mitchell and Johns in a recent paper. The dashed line uses an unrealistic CO2 concentration of 859 ppm by 2050. The solid line estimates warming if the most likely concentration, as given by the United Nations, is used. BOTTOM: Temperatures predicted by the new NCAR model. The dashed line increases effective CO2 at 1 percent per year, but the known increase is 0.7 percent per year. The solid line estimates warming using the right value. The nominal starting time is around 1965.

This exercise is getting familiar. We had to do the same thing to the new model from the United Kingdom Meteorological Office (UKMO), featured in our May 12 edition. When we did, we got a total warming of only 1.5oC out to 2100 and a net change of only 1.2oC from current temperatures. When we do the same to the NCAR model, we get a change of 1.3oC from current temperatures.

So removing the fudges removes most of the warming! Pesky!

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