TCS Daily

Just Ask the Experts

By Sallie Baliunas - July 23, 2002 12:00 AM

In 2001 the National Science Foundation surveyed 1,500 people nationwide and found that 77% believed that "increased carbon dioxide and other gases released into the atmosphere will, if unchecked, lead to global warming ..." Yet half of those polled believed that humans and dinosaurs co-existed on Earth, despite the scientific fact that the dinosaurs went extinct tens of millions of years before the earliest hominids appeared. Worse, only 22% of the respondents understood what a molecule - for example, carbon dioxide - is.

As in the case of the belief by many that dinosaurs and early humans co-existed, public opinion does not change the actual facts about the material world. Such a poll measures nothing more than the degree of public ignorance about scientific matters.

Most people get news stories about science and technology developments from television. And after more than a decade of being fed what-if stories about global warming from human activities, no wonder most people "believe" that global warming "will" occur. However, on the anxiety scale, only 33% "worry a great deal" about global warming, a worry that ranks at 12 out of 13 environmental concerns. The top environmental fear, shared by 64% of those polled, was polluted drinking water.

So What Do We Know?

Concerning the latest understanding on human-made global warming, here are three points we know from the science:

  1. The surface record of temperature from thermometers show widespread warming in the 20th century compared to the 19th. There was one period of warming early in the 20th century, the second after the 1970s. Ecosystems have responded to this widespread warmth, not seen since ca. 800 - 1200 C.E.

    But the cause of global surface warming cannot be associated with human activity without additional information. Some media reports point to ecosystem responses of 20th century warmth (e.g., mountain glacier retreat) and unjustifiably claim the responses owe to man-made causes. But mountain glaciers receded during the past period of warmth around 1,000 years ago, and advanced during the unusual cold of the Little Ice Age (ca. 1300 - 1900 C.E.). Both those climate shifts occurred naturally, before the increased concentration of human-made greenhouse gases in the air.

  2. All computer simulations of climate say that in order to conclude that the surface global warming trend is human caused, the surface warmth must be accompanied by an equal or larger warming trend in the air from one to five miles in height. Measurements made by satellites and verified from weather balloons show no meaningful human-made warming trend over the last two or even four decades. Thus, the recent warming trend in the surface temperature record cannot be caused by the increase of human-made greenhouse gases in the air.

  3. The computer simulations are not reliable as tools for explaining past climate or making projections for future trends.

Future Shock: The Scenarios

When it comes to future scenarios, consider what the experts actually say about potential climate change. The United Nations Intergovernmental Panel on Climate Change writes in its Special Report on Emissions Scenarios (2000), "Scenarios are images of the future or alternative futures. They are neither predictions nor forecasts." Further, "The possibility that any single emissions path will occur as described in the scenario is highly uncertain," and finally, "No judgement is offered in this Report as to the preference for any of the scenarios and they are not assigned probabilities of occurrence, neither must they be interpreted as policy recommendations."

Forecasting future societal conditions and energy use often amount to little more than unconvincing guesses. Jesse Ausebel at Rockefeller University in April 2002 critiqued the U.N. IPCC's " ... 40 energy scenarios, with decarbonization, or carbonization, sloping every which way and no probabilities attached. ... It is a confession that collectively they know nothing, that no science underlies their craft, and that politics strongly bias their projections."

Nonetheless, such a guess about the world's energy future forms the first step in making a 100-year prediction of global warming. That first uncertain forecast - future energy use - used as input in the climate simulation surely compounds the uncertainty in the next step, the climate forecast.

Inability to predict the future should not be surprising. The climate simulations upon which predictions are based yield unreliable results because, as outlined above, the results are incompatible with measurements of how the climate has changed in the last few decades.

Complete Speculation

On May 24, 1994, Richard Lindzen, the Alfred P. Sloan Professor of Meteorology at MIT, testified to the Senate Committee on Energy and Natural Resources, "The claims about catastrophic consequences of significant global warming, should it occur at all, are almost completely speculative. Not only are they without any theoretical foundations, but they frequently involved assuming the opposite of what appears to happen."

Despite years of solid work by climate specialists, the output of computer simulations remains undependable, owing to the extraordinary complexity of the natural world. Thus, on May 1, 2001 Lindzen testified to the Senate Commerce Committee about the long-standing inability of computer simulations to deliver results that resemble reality, even in the cases where good measurements are available:

"For example, there is widespread agreement [among climate scientists] ... that large computer climate models are unable to even simulate major features of past climate such as the 100 thousand year cycles of ice ages that have dominated climate for the past 700 thousand years, and the very warm climates of the Miocene [23 to 5 million years ago], Eocene [57 to 35 million years ago], and Cretaceous [146 to 65 million years ago]. Neither do they do well at accounting for shorter period and less dramatic phenomena like El Ninos, quasi-biennial oscillations, or intraseasonal oscillations - all of which are well documented in the data, and important contributors to natural variability."

Lindzen explained the failure of computer simulations simply in May 2000:

"The point I am making is that it is a fallacious assumption that the models have everything in them, and will display it, and somehow the rest is just technical uncertainty. There are things they literally don't have."

This punctuates the popular notion that averaging output from computer results will somehow, miraculously, give a scientifically appropriate result.

Think Locally

Now, on top of the unreliable forecasts of global warming -- which rest on "highly uncertain" forecasts of future economic and social conditions and un-validated climate simulations -- come the forecasts of local impacts, in order to make the case for relevancy to people. Increased storminess is one prediction of the outcome of human-made global warming found in the popular media, which would be where most people learn about the issue.

The idea that storminess increases with human-made global warming defies expert opinion. David Legates, an expert hydrology researcher, testified in the Senate Committee on Environment and Public Works on March 13, 2002:

"Ascertaining anthropogenic changes to these extreme weather events is nearly impossible. Climate models cannot even begin to simulate storm-scale systems, let alone model the full range of year-to-year variability... Clearly, claims that anthropogenic global warming will lead to more occurrences of droughts, floods, and storms are wildly exaggerated."

The U.N. IPCC Third Assessment Report concurs, "[T]here is currently insufficient information to assess recent trends, and climate models currently lack the spatial detail required to make confident projections. For example, very small-scale phenomena, such as thunderstorms, tornadoes, hail and lightning, are not simulated in climate models (Summary for Policymakers, p. 15)."

A group of extremely relevant experts, the American Association of State Climatologists, recently summarized the state of climate simulations:

"Climate prediction is complex with many uncertainties ... For time scales of a decade or more, understanding the empirical accuracy of such predictions - called "verification" - is simply impossible, since we have to wait a decade or longer to assess the accuracy of the forecasts. ... climate predictions have not demonstrated skill in projecting future variability and changes in such important climate conditions as growing season, drought, flood-producing rainfall, heat waves, tropical cyclones and winter storms. These are the type of events that have a more significant impact on society than annual average global temperature trends."

On the facts of human-made global warming, should one believe television or the experts?



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