With the 2023 publication of Climate Uncertainty and Risk: Rethinking Our Response, geoscientist Judith A. Curry, Ph.D., acknowledges that, in 2007, she “joined the consensus” in supporting the UN’s Intergovernmental Panel on Climate Change’s (IPCC) Fourth Assessment Report as “authoritative.” What changed her perspective was Climategate, the 2009 hacking and unauthorized release of emails from the Climatic Research Unit at the University of East Anglia. The email exchanges between climate scientists and IPCC authors confirmed her “concerns and suspicions” that “politics and personal agendas” had encroached on the IPCC assessment process.
In 2017, Curry resigned from a prestigious faculty position as chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology. “As a result of the polarization of climate science, I found that I had lost my love of science in the context of the academic ecosystem,” she admits.
Curry is currently employed in the private sector as president of Climate Forecast Applications Network (CFAN), a company she co-founded in 2006 under Georgia Tech’s VentureLab program. There she is involved in “real-world decision-making to manage weather- and climate-related risks.” She also created the highly respected blog Climate Etc., for which she has written numerous posts.
In her new book, Curry acknowledges that a changing climate “has been the norm throughout the Earth’s 4.6-billion-year history.” She refuses to abandon the idea that we humans “are also changing atmospheric composition by increasing the emissions of CO2 and other greenhouse gases,” but she adds an important caveat:
This redefinition of “climate change” to refer only to human-caused changes to the atmospheric composition has effectively eliminated natural climate change from the public discussion.
The result is that the common parlance refers to “climate change,” with no mention of natural climate variability. Any change that is observed over the past century is now implicitly assumed to be caused by human emissions to the atmosphere. This assumption leads to connecting every unusual weather or climate event to human-caused climate change from fossil fuel emissions. Having acknowledged that climate change is the “norm” throughout the Earth’s 4.6-billion-year history, Curry understands that this politicized attribution of all climate change to humans burning hydrocarbon fuels is nonsense.
The crux of Curry’s argument is mathematical, and her main goal is to redefine how computer-driven climate models are conceptualized. What Curry understands is what MIT mathematician and meteorologist Edward Norton Lorenz proved with what has become known as the “butterfly effect.” Lorenz demonstrated that the mathematics of climate involve nonlinear differential equations in which a change in an independent variable does not produce a deterministic outcome in related dependent variables.
In his book The Essence of Chaos, Lorenz also demonstrated that small differences in initial measurements can produce dramatic differences in climate model outcomes. So, a butterfly flapping wings in China might affect tornados developing in Kansas, but sometimes when a butterfly flaps its wings in China, there is no effect on tornados in Kansas. The flapping of wings is a small difference in an initial measurement that can cause a huge effect on climate outcomes. But the fact that the wings flapping in China does not always cause a tornado in Kansas is because the equations ruling climate are nonlinear, so sometimes the butterfly causes a tornado, and sometimes it does not.
In other words, weather is not predictable, nor can we determine with precision the precise amount of global warming, if any, that will result from a given increase in atmospheric CO2. This is why Curry abandoned the hope that climate can be modeled deterministically by a computer and, instead, insists that the uncertainties inherent in climate mean that, at best, our weather and climate predictions are uncertain, measurable only by probability theory.
Curry, like Lorenz, concluded that the nonlinear nature of climate equations and the inherent limitations of making quantitative measurements of climate variables (in a mathematics that involves irrational numbers with endless decimal places) doom all climate models to failure. She writes, “Many processes in atmosphere and oceans are nonlinear, which means there is no simple relation between cause and effect.” She concludes “the inherent unpredictably of the climate system” dooms all computer weather models to failure in a deterministic sense, noting that “for weather, this predictability timescale is a matter of weeks.”
While Curry is careful not to antagonize the global warming hysterics that dominate the intellectual world today, what she has just said is that IPCC models dictating we must limit global temperatures to no more than 1.5°C above preindustrial levels within the next thirty years to prevent catastrophic global warming reflect political bias, rather than conclusions drawn from legitimate climate science.
Curry favors changing the climate paradigm from deterministic thinking producing apocalyptic scenarios of dystopian climate futures to a probabilistic model that acknowledges the uncertainties of outcomes inherent to Earth’s climate. Instead of discarding computer-driven climate models, she wants to abandon using them as “prediction machines” in favor of using them as “scenario generators.”
The bottom line of Curry’s concern is that our understanding of Earth’s climate is limited, such that even possible climate outcome scenarios generated by elaborate climate models can, at best, be determined to be possibilities, not certainties. That we must rely on climate probabilities is another huge admission, given the cataclysmic nature of Earth’s changes in geologic time—the rise of mountains, the movement of continents, and the impact of asteroids, to name a few. Earth experienced five massive extinctions of nearly everything living before homo sapiens appeared.
That a geoscientist of Judith Curry’s magnitude should be willing to criticize the IPCC global warming establishment on the mathematics of their climate models is earth-shaking. Without their climate models, the IPCC lose their thunder. predicting climate catastrophes. Once Curry embraced Lorenz, she abandoned Michael Mann forever. The dirty secret of Curry’s important book is that it exposes the IPCC attack on CO2 as just another politicized iteration of the familiar neo-Marxist animosity to hydrocarbon fuels for providing the abundant and affordable energy capitalism needs to maintain the modern industrial state.
Photo: Judith Curry.
Source: American Thinker.
