Monday, February 27th 2012, 2:03 PM EST
Climate-impact models combine projections of change in physical climate with data on population, economic growth and other variables. The output of such models are used to make predictions regarding the cost of anthropogenic global warming, in both monetary and human terms. They are the source of dire predictions used to scare politicians and bludgeon the public into accepting draconian measures to curb human CO2 emissions. Unfortunately for the prophets of climate change catastrophe, the models' reports are far from being in agreement, leading more rational members of the public to doubt the models' veracity. To rectify this lack of believability, a new “fast-track” program to coordinate modeling studies and make “their narratives of possible futures more coherent and useful to decision-makers,” has been launched. In other words, it is an attempt to make sure that climate change propaganda is at least consistent.
Most followers of the climate change controversy are familiar with general circulation models (GCM), complicated computer models that attempt to simulate Earth's climate system and make predictions regarding humanity's impact on the environment. What is not often discussed are a second class of models that are used to predict the result of climatic change: climate-impact models. “For various emissions scenarios, they forecast climate-driven changes in crop yields, vegetation zones, hydrology and human health,” states Quirin Schiermeier in “Models hone picture of climate impacts,” a news focus article in the February 16, 2012, issue of the journal Nature.
That article announced that researchers at the Potsdam Institute for Climate Impact Research (PIK) in Germany, recently launched a fast-track program to make the model predictions of possible futures more consistent. Evidently, it is hard to convince even sympathetic politicians and government ministers that the sky is falling when none of your dozens of models predict the same outcomes. The ‘refined’ models will still give a range of answers — but the modelers hope that the remaining diversity will be informative rather than confusing. Quoting from the article:
They often leave out important elements: for example, models of health impact often neglect the role of social factors in spreading disease; and models of water run-off may not account for changes in water loss from plants. Researchers have built dozens of models, but have never systematically compared their performance. As a result, say critics, the literature on climate impacts is as inconclusive as it is encyclopaedic.
Of course, this is nothing new. Similar models have been shown to be unreliable in the past. According to Pavel Kabat: “Impact models have never been global, and their output is often sketchy. It is a matter of responsibility to society that we do better.” Kabat is the director of the International Institute for Applied Systems Analysis in Laxenburg, Austria, which is to coordinate the fast-track program jointly with the PIK. To fix this credibility problem the program, dubbed the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), will coordinate the efforts of more than two dozen modelling groups from eight countries. Reportedly:
At the kick-off meeting at the PIK, the researchers agreed to complete a comprehensive set of model experiments within six months. All the simulations will cover the globe at the same resolution, and will be based on the same set of climate data from state-of-the-art climate models, driven by the latest greenhouse-gas emission scenarios.
As an example of the type of result they are aiming for, consider the two maps shown below. They were generated by the PIK based on the combined temperature and precipitation projections from 19 GCMs to predict the “most likely regions of vegetation loss.” Predictions for two different temperature increase scenarios are shown.
What is not obvious is that these results are from a model based on combining the output of nearly a score of models that do not agree. The GCM results themselves are based on the latest greenhouse-gas emission scenarios, which have been shown to be unrealistic and based on bogus assumptions. In other words, this new project is going to try and make more believable impact projections by combining the erroneous output of dozens of GCM, running them through dozens of impact models (which also do not agree) and then combining everything into a more harmonious set of predictions. “We’ll never be able to tell exactly what the future will look like,” says Ottmar Edenhofer, chief economist at the PIK, “but we can illuminate plausible paths.”
There is a well know saying among those who deal with data smoothing and forecasting (of which I am one). That saying is “you smooth crappy data and you get smoothed crap for a result.” With computer models, adding erroneous results together does not result is a less erroneous answer—usually the opposite result occurs. The only conclusion a rational person can come to is that this “fast-track” program is an attempt to have the impact modeling community speak with a single voice, or at least more harmonious chorus of voices, in hopes of making their crap results more believable.
By January 2013, the project hopes to produce papers detailing the impact of climate change on global agriculture and water supplies, vegetation and health. The participants fondest wish? That the results find their way into the next report of the Intergovernmental Panel on Climate Change (IPCC), which is scheduled to be published in 2013–14. “It will make a real difference for the assessment process,” says Chris Field, an ecologist at the Carnegie Institution for Science in Stanford, California, and co-chairman of the IPCC’s working group on impacts, adaptation and vulnerability. That's right, the perpetrators of this little exercise in computer modeling legerdemain aspire to be accepted by the IPCC, the UN agency that has done more to damage the credibility of science than any organization in the history of humankind.
Can any rational person put their faith in such efforts? Take incomplete and often erroneous science to build a first set of climate modes, then use the biased and contradictory output from those models to feed a second, even less harmonious set of models to tell what damage might occur in the future. Do they really believe that presenting us with a single wrong answer will be more convincing than the plethora of trash they currently peddle to the public? And they called Nostradamus a charlatan. This is junk science twice removed from reality, which no thinking person should believe.
Be safe, enjoy the interglacial and stay skeptical.