Global Warming Predictions Invalidated
A new study in the journal Science has just shown that all of the climate modeling results of the past are erroneous. The IPCC's modeling cronies have just been told that the figures used for greenhouse gas forcings are incorrect, meaning none of the model results from prior IPCC reports can be considered valid. What has caused climate scientists' assumptions to go awry? Short lived aerosol particles in the atmosphere changing how greenhouse gases react in previously unsuspected ways. The result is another devastating blow to the climate catastrophists' computer generated apocalyptic fantasies.
In a stunning article entitled “Improved Attribution of Climate Forcing to Emissions,” a group of researchers from NASA's Goddard Institute for Space Studies and Columbia University in New York, led by Drew T. Shindell, have called into question the values used to calculate the “forcing” due to various greenhouse gases. “We calculated atmospheric composition changes, historical radiative forcing, and forcing per unit of emission due to aerosol and tropospheric ozone precursor emissions in a coupled composition-climate model,” states the paper's abstract. “We found that gas-aerosol interactions substantially alter the relative importance of the various emissions. In particular, methane emissions have a larger impact than that used in current carbon-trading schemes or in the Kyoto Protocol.”
According to the study, emissions of NOx, CO, and methane have substantial impacts on aerosols by altering the abundance of oxidants, especially hydroxyl, which convert SO2 into sulfate. Global abundance of hydroxyl and sulfate changes by 18% and 13% for increased NOx by significant amounts. By –13% and –9% for CO, and by –26% and –11% for methane. Coupling in the other direction is very weak because reactions of gases with aerosols only have a small effect on the amounts of radiatively active ozone and methane. For example, SO2 emissions enhance the removal of NOx through reactions on particulate surfaces, causing ozone to decrease, but the radiant forcing is only –0.004 W/m2. Increased SO2 leads to substantially reduced nitrate aerosol, however, owing to greater ammonium sulfate formation at the expense of ammonium nitrate.
Figure 1. Radiative forcing from 1750 to 2000. Numerical values within the figure give the net forcing (instantaneous at the tropopause). Uncertainties in the abundance-based values are 0.16 for CO2, 0.05 for methane, +0.15 to –0.10 for ozone, 0.20 for sulfate, 0.10 for nitrate, and 0.05 for stratospheric water. For emissions-based values, we estimate uncertainties by adding the forcing uncertainties for each component in quadrature, yielding 0.14 for methane, 0.04 for CO+VOCs, 0.09 for NOx, 0.23 for sulfate, and 0.10 for ammonia. AIE are not included. All forcing values are from this work except those from CO2 and stratospheric water, which are based on the IPCC AR4. From Shindall et al., Science 2009.
This is not the first time that Shindell has published research on aerosols and their impact on climate change, but this study is a step beyond that previous work. The importance of this revelation is underlined by the two perspective articles that accompany the paper in the October 30, 2009, issue of Science. In one perspective, entitled “Clean Air for Megacities,” David D. Parrish and Tong Zhu, noting that over half of humanity now lives in cities, stress that reducing particulate emissions in major cities is essential to controlling climate change. Again there is an open admission of scientific ignorance:
Major scientific challenges lie in understanding the dual role of particulate matter as the air pollutant with the greatest health impacts, and as both a cooling and a warming agent for climate. On balance, particulate matter in the atmosphere is believed to presently compensate for a large fraction of the warming effects of greenhouse gases, but there is large uncertainty in our understanding of its net climate effects and on the different time and space scales on which particulate matter affects climate.
The question of time scales becomes very important here. Most GHGs remain in the atmosphere for years, even decades, while aerosols are thought to be relatively short lived. This has led to speculation that climate change can be controlled (“mitigated”) by controlling aerosol emissions. This idea is expanded upon by Almut Arneth et al. in their perspective entitled “Clean the Air, Heat the Planet?” They state: “There is thus a strong motivation for treating air pollution control and climate change in common policy frameworks. However, recent model studies have shown that changes in pollutant and precursor emissions, atmospheric burden, and radiative forcing are not necessarily proportional.” In short, there are non-linear response at work here.
Areneth et al. restate the assertion by Shindell et al. that current models do not capture many of the complex atmospheric processes involving aerosols and reactive trace gases. In other words, current climate models are to simplistic, ignoring the importance of aerosols and their interactions with GHG. Even so, they are convinced that controlling particulate pollution could be the key to controlling climate change:
The idea that air pollution control could help to mitigate climate change, buying time until greenhouse gas reductions take effect, seems attractive, because air pollutants are short-lived in the atmosphere compared with CO2 and other greenhouse gases. The radiative forcing of these short-lived species is uncertain but may be large. The contribution of anthropogenic ozone to global warming may be twice the mean Intergovernmental Panel on Climate Change (IPCC) value of +0.35 W m-2. Ramanathan and Carmichael have inferred a forcing of +0.9 W m-2 for current black carbon levels—more than half the value of the current CO2 forcing. Assuming a climate sensitivity of 2° to 4°C for a doubling of CO2, elimination of black carbon emissions could decrease global surface temperature by 0.5° to 1°C.
This would imply that if aerosols—black carbon in particular—were reduced we should see global cooling. And this is using the IPCC values for CO2 sensitivity. So much for the potency of CO2 as the major driver of climate change. But the researchers are not sure what effect a reduction in aerosols would have. Particulate pollution control could have the opposite effect, accelerating climate warming.
Much of what they knew was wrong and much remains to be added.
If reduction of short-lived pollutants with negative forcing—especially sulfate aerosols—outweighs the reduction of those with positive forcing things would heat up instead. Some climate sensitivity analyses suggest temperature increases well above IPCC estimates for all but the lowest estimates of net aerosol forcing. Changes in the atmospheric aerosol load may thus lead to a strong greenhouse gas warming response. Areneth et al. conclude by saying: “Direct and indirect interactions between climate change, land ecosystems, and chemistry can amplify or dampen the climate effects of air pollutants, but are poorly represented in models.” This should come as a shock to no one.
Mojib Latif, a climate scientist in Germany, is co-author of a paper predicting the planet will cool for perhaps a decade before starting to warm again—a long-term trend based on human greenhouse gas emissions. He attributes the cooling to cyclical changes in the atmosphere and ocean currents in the North Atlantic, known as the North Atlantic Oscillation (NAO) and the Atlantic Meridional Oscillation (AMO). Conditions in the Pacific will remain pretty much as they are.
Of course, this prediction also relies on models. “There is a lot of room for improvement” in the models, says Latif. “You need to know what you can believe and can't believe from the models.” It seems that occasionally a model will come up with a prediction that actually happens. This is analogous to the old saying “even a blind pig finds an occasional acorn.” The problem is, no one knows ahead of time which acorn the pig will find or which model prediction might be right.
Ocean water temperatures from NOAA's CM2.4 climate model.
The final conclusion from Shindell et al. was this: “Finally, our results demonstrate that improving our knowledge of aerosol-climate interactions is important not only for better understanding the aerosol contribution to past and future climate change, but even for correctly evaluating the effects of long-lived greenhouse gas emissions from methane-oxidant-aerosol interactions.” Scientist speak for “we've got it wrong in the past and don't know what the right answers are.”
This comes on the heels of previous reports about things science didn't know. Over just the past year there have been revelations about couplings between the lower and upper atmosphere (see “Atmospheric Solar Heat Amplifier Discovered”), the carbon cycle (see “New "Jelly Pump" Rewrites Carbon Cycle”), ocean circulation (see “Conveyor Belt Model Broken”), and the importance of water vapor (see “Climate Models Blown Away By Water Vapor” and “More Water Vapor Woes For Climate Modelers”). I have read scores of journal articles that say “the models need to be changed,” or words to that effect.
Models are only as good as the information they are built on. GCM consist of dozens of equations written to reflect how liquids and gases, driven by energy from the Sun, move about the planet. If the coefficients used in those equations to represent the impact of various GHG and aerosols are in error, then the equations are wrong—they do not represent physical reality. If the equations are wrong then the models can not be right. Furthermore, when climate modelers tweak their playthings to match previous periods of climate variation, a practice called backcasting, they are actually proving that even an incorrect model can be made to match an arbitrary set of test data.
Since the parameters contained in the models are incorrect they should not match the test data. Tuning models to do so means that the GCM used to predict future conditions are actually incorrect models, improperly tuned! Little wonder no model managed to predict the current halt in global warming. And even if they had it would have been a blind pig finding an acorn—an incorrect prediction that just happened to match what took place in the real world. The fundamental conclusion is simple, no climate model prediction from the past thirty years can be trusted.
Be safe, enjoy the interglacial and stay skeptical.
A number of readers have commented in other forums that the paper quoted in this article supports the AGW hypothesis. One particularly dim bulb added up all of the adjusted forcings and, arriving at a higher total number, said “see, things are worse!” This is not the correct way to interpret this information. There are two major consequences of the changed forcing values:
- Changing the forcing values in no way changes the amount of historical temperature change. This means that all of the forcings resulted in the same ΔT. Because the forcing attributed to CO2 is now a smaller portion of the total, the effectiveness of CO2 as a cause of global warming is diminished.
- This also implies that, since the models were tuned to return a specific amount of temperature rise for a doubling of atmospheric CO2 (the “sensitivity”), the model response to carbon dioxide is incorrectly calibrated. Since other forcings contributed more to the temperature rise, CO2 had a smaller impact for a given increase. Instead of the IPCC's 2-6°C sensitivity range a lower range would be more appropriate (some have suggested that true climate sensitivity is around 0.5°C).
This analysis is about as simplistic as adding up the forcing values then proclaiming things are worse, and should be taken with a grain of salt. If it were possible to total up the forcings and do a linear estimation of temperature change we would not need complex and very expensive computer models to provide us with climate change predictions. It was discovered long ago that Earth's climate system is far to complex to behave so simplistically. Atmospheric CO2 levels do not act like a thermostat, raising and lowering the world's temperature as though turning a knob.
As a result, governments around the world have poured more than $80 billion into climate modeling over the past 30 years and still have precious little to show for it. To repeat what I stated in the main article, there are many newly discovered missing factors that need to be incorporated into the GCM. Rejiggering the forcing values due to previously omitted chemistry taking place in the atmosphere is just one of them. I repeat, the results of all earlier models are all in error. No stock should be put in their results, even if they happen to reinforce your personal, unscientific beliefs.