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Carbon Dioxide and Earth's Future: Pursuing the Prudent Path

Executive Summary

As presently constituted, earth's atmosphere contains just slightly less than 400 ppm of the colorless and odorless gas we call carbon dioxide or CO2. That's only four-hundredths of one percent. Consequently, even if the air's CO2 concentration was tripled, carbon dioxide would still comprise only a little over one tenth of one percent of the air we breathe, which is far less than what wafted through earth's atmosphere eons ago, when the planet was a virtual garden place. Nevertheless, a small increase in this minuscule amount of CO2 is frequently predicted to produce a suite of dire environmental consequences, including dangerous global warming, catastrophic sea level rise, reduced agricultural output, and the destruction of many natural ecosystems, as well as dramatic increases in extreme weather phenomena, such as droughts, floods and hurricanes.

As strange as it may seem, these frightening future scenarios are derived from a single source of information: the ever-evolving computer-driven climate models that presume to reduce the important physical, chemical and biological processes that combine to determine the state of earth's climate into a set of mathematical equations out of which their forecasts are produced. But do we really know what all of those complex and interacting processes are? And even if we did -- which we don't -- could we correctly reduce them into manageable computer code so as to produce reliable forecasts 50 or 100 years into the future?

Some people answer these questions in the affirmative. However, as may be seen in the body of this report, real-world observations fail to confirm essentially all of the alarming predictions of significant increases in the frequency and severity of droughts, floods and hurricanes that climate models suggest should occur in response to a global warming of the magnitude that was experienced by the earth over the past two centuries as it gradually recovered from the much-lower-than-present temperatures characteristic of the depths of the Little Ice Age. And other observations have shown that the rising atmospheric CO2 concentrations associated with the development of the Industrial Revolution have actually been good for the planet, as they have significantly enhanced the plant productivity and vegetative water use efficiency of earth's natural and agro-ecosystems, leading to a significant "greening of the earth."

In the pages that follow, we present this oft-neglected evidence via a review of the pertinent scientific literature. In the case of the biospheric benefits of atmospheric CO2 enrichment, we find that with more CO2 in the air, plants grow bigger and better in almost every conceivable way, and that they do it more efficiently, with respect to their utilization of valuable natural resources, and more effectively, in the face of environmental constraints. And when plants benefit, so do all of the animals and people that depend upon them for their sustenance.

Likewise, in the case of climate model inadequacies, we reveal their many shortcomings via a comparison of their "doom and gloom" predictions with real-world observations. And this exercise reveals that even though the world has warmed substantially over the past century or more -- at a rate that is claimed by many to have been unprecedented over the past one to two millennia -- this report demonstrates that none of the environmental catastrophes that are predicted by climate alarmists to be produced by such a warming has ever come to pass. And this fact -- that there have been no significant increases in either the frequency or severity of droughts, floods or hurricanes over the past two centuries or more of global warming -- poses an important question. What should be easier to predict: the effects of global warming on extreme weather events or the effects of elevated atmospheric CO2 concentrations on global temperature? The first part of this question should, in principle, be answerable; for it is well defined in terms of the small number of known factors likely to play a role in linking the independent variable (global warming) with the specified weather phenomena (droughts, floods and hurricanes). The latter part of the question, on the other hand, is ill-defined and possibly even unanswerable; for there are many factors -- physical, chemical and biological -- that could well be involved in linking CO2 (or causing it not to be linked) to global temperature.

If, then, today's climate models cannot correctly predict what should be relatively easy for them to correctly predict (the effect of global warming on extreme weather events), why should we believe what they say about something infinitely more complex (the effect of a rise in the air's CO2 content on mean global air temperature)? Clearly, we should pay the models no heed in the matter of future climate -- especially in terms of predictions based on the behavior of a non-meteorological parameter (CO2) -- until they can reproduce the climate of the past, based on the behavior of one of the most basic of all true meteorological parameters (temperature). And even if the models eventually solve this part of the problem, we should still reserve judgment on their forecasts of global warming; for there will yet be a vast gulf between where they will be at that time and where they will have to go to be able to meet the much greater challenge to which they aspire.

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