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Carbon Dioxide and Global Environmental Change:
The Proper Roles of Reason and Religion in Developing Policies Related to Anthropogenic CO2 Emissions

Volume 4, Number 27: 4 July 2001

At their June 2001 General Meeting, the assembled body of U.S. Catholic bishops gave their stamp of approval to a document entitled Global Climate Change: A Plea for Dialogue, Prudence, and the Common Good, which was released to the world on 15 June 2001 via its publication by the United States Catholic Conference, Inc., Washington, DC.  In preparing this "Statement of the U.S. Catholic Bishops," the prelates did the world an important service by injecting a much-needed moral dimension into the sometimes acrimonious debate that rages over what should be done -- or not done -- about the ongoing rise in the air's CO2 content.  This religious perspective deserves to be carefully considered by people of all faiths, which we do here, as we respond to the bishops' "plea for dialogue, prudence, and the common good."

We begin our part of the dialogue by examining the primary guiding principle laid down in the first paragraph of the bishops' treatise, which states "we believe our response to global climate change should be a sign of our respect for God's creation."  We heartily endorse this general concept, i.e., the idea that our response to any true environmental problem should be based on a profound respect for all that God called good at the time of his creative enterprise.  However, we temper our enthusiasm for the bishops' selection of the specific subject to which they apply this "response principle," for in their choice of global climate change as the phenomenon of concern, they make a number of implied assumptions that may not be true, including (1) global climate is changing, (2) man is responsible for the change, (3) the change is undesirable, and (4) man can do something to reverse the change.  Unless these four assumptions are all true, the application of the bishops' response principle to the phenomenon on which they focus their attention has little virtue; for absent the demonstrable veracity of these assumptions, the supposed problem -- global climate change -- may well be (1) no problem at all, (2) a problem not caused by man, (3) a beneficial phenomenon, or (4) something about which nothing can be done, which could well make extreme -- but largely ineffective -- ameliorative actions counterproductive to the common good the bishops so fervently hope to promote.

A more logical approach to the subject would be to focus on the phenomenon the bishops assume to be the cause of global climate change, which is also the phenomenon that everyone who seeks to do something about the perceived problem wants to modify, i.e., the ongoing rise in the air's CO2 content.  In addition to being more logical, this approach also alleviates two of the four major problems associated with the bishops' approach to the issue.  With respect to their contentious first assumption, for example, which within the framework of our approach to the subject would posit that atmospheric CO2 enrichment is occurring, everyone on both sides of the CO2-climate debate is already in agreement, as the air's CO2 content has been confirmed by direct measurement over the past four decades to be clearly rising.  Furthermore, analyses of ancient air trapped in polar ice suggest that the atmosphere's CO2 concentration has been rising ever since the inception of the Industrial Revolution; and this observation goes a long ways towards establishing -- but by no means proving -- the truth of the second assumption of our approach to the problem, i.e., the claim that man is responsible for the ongoing rise in the air's CO2 content.  Hence, whereas the bishops' approach left us with four contentious assumptions that were all highly debatable, our approach brings us nearly halfway to the point of complete consensus!

With this good progress behind us, we will now evaluate assumption number three within the context of our reformulation of the issue, i.e., the claim that the ongoing rise in the air's CO2 concentration is undesirable; and in considering this claim, we will proceed in two sequential steps, looking first at the direct effects this phenomenon might have on God's earthly creations and secondly at the indirect effects it may have.

In the realm of direct effects, there are two major divisions of God's animate creation that may be significantly impacted by atmospheric CO2 enrichment: plants and animals.  With respect to animals, we note that the air's CO2 concentration would have to rise by a factor of 40 or more before deleterious effects would begin to manifest themselves (see our Subject Index entry Does High CO2 Harm Humans?).  We also note there are probably not enough fossil fuels in the crust of the earth to accomplish this feat, even if all recoverable reserves were completely extracted and burned.

With respect to plant life, we encounter a somewhat different situation: we need not worry about any direct deleterious effects of atmospheric CO2 enrichment, for there are none!  Right from the very first whiff of extra CO2, nearly all of earth's plants respond by doing everything they do better than they do under current atmospheric CO2 concentrations.  They typically grow bigger and faster, producing more and larger leaves, more and larger roots, more and larger flowers, more and larger seeds, grains and fruit, and on and on, as is demonstrated by the many biological Journal Reviews posted on our web site that describe direct experimental investigations of these subjects.  In addition, there are literally thousands -- and that is no exaggeration -- of other such studies not highlighted on our web site that show the very same things.

These facts have become so well established over the past several decades that many scientists are now directing their attention to investigating the propensity for atmospheric CO2 enrichment to not only induce plants to produce more biomass, but to promote the production of greater concentrations of health-promoting and medicinal substances within that biomass, as noted in our reviews of the papers of Idso et al. (2000) and Idso and Idso (2001).  This effect of atmospheric CO2 enrichment could well provide a number of health benefits to humans and animals alike, as the foods they eat become more nutritious and provide greater protection against a number of degenerative diseases, including cancer, cardiovascular disease and immune system decline.  In fact, it is possible that the people of the earth and its animal life may already be benefiting from these potential CO2-induced improvements in their diets, as noted in our editorial of 20 June 2001.

In light of these well-documented observations of the many direct beneficial effects of atmospheric CO2 enrichment on earth's plant life (most of which are proven, but some of which are still conjectural), the assumption that the ongoing rise in the air's CO2 content is undesirable would appear -- at this stage of the analysis, at least -- to be fully one hundred and eighty degrees out of phase with reality.  And so it likely is, for with less CO2 in the air than the air holds now, plants do not grow nearly as well as they do currently; while with more CO2 in the air, they generally grow much better.  In addition, with higher levels of plant productivity, greater populations of animals can be sustained, which helps to promote ecosystem biodiversity, since for each species there is a certain "critical biomass" that must be maintained to preserve its specific identity.

These direct biological consequences of atmospheric CO2 enrichment are highly germane to the question of whether something should -- or should not -- be done to reduce anthropogenic CO2 emissions to the atmosphere; yet in the bishops' formulation of the "problem," there is not the slightest hint that anything good could ever come from atmospheric CO2 enrichment.  Hence, it is clear that their approach to the issue lacks "prudence," to borrow an appropriate word from the title of their treatise, and that it may not be in the best interest of the biosphere's "common good," to borrow two others.

We turn next to the possible indirect effects of the ongoing rise in the air's CO2 content, which is where the bishops errantly (and dangerously!) began their analysis of the issue, by considering the potential for atmospheric CO2 enrichment to promote global warming.  This subject is much more complex than that of CO2's direct effects on God's animate creation; for it involves a host of phenomena about which we know little more than that they may (or may not) play important roles in global climate change, which is the route by which atmospheric CO2 enrichment is envisioned by the bishops to negatively impact earth's biosphere.

Suffice it to say, in this regard, that many dire things have been predicted to occur to nearly all forms of terrestrial and aquatic life on the basis of climate model predictions of catastrophic CO2-induced global warming, based on predicted future increases in atmospheric CO2 concentration and all sorts of assumptions about how various physical, chemical and biological phenomena might (or might not) interact with each other.  What we essentially have in this situation, therefore, is a highly tentative and tortuous trail leading from anthropogenic CO2 emissions to sundry doomsday scenarios that spell devastation as severe as extinction for many types of life forms.

Acting on the basis of this aspect of the issue only, i.e., on the basis of CO2-induced global warming predictions and their presumed negative consequences, the U.S. Catholic bishops do a great disservice to the concept of prudence they so seriously plead for others to embrace.  We must always remember, for example, that the issue is what to do about the ongoing rise in the air's CO2 concentration.  To decide this issue, it is not only prudent, but a logical necessity, that all consequences of atmospheric CO2 enrichment be evaluated.  And herein is where the bishops failed to abide by their own admonition; they only considered the presumed negative consequences of the ongoing rise in the air's CO2 concentration, not even acknowledging the existence of the many well-established positive consequences of this phenomenon.  Such an approach, i.e., keeping the masses in the dark about important and pertinent facts, may well be an effective way to win a public policy debate, but it is certainly no way to seek the common good.

It behooves us, therefore, to walk the path the bishops failed to tread, and consider both the positives and negatives of the case in question.  In beginning this trek, we note that on the one hand we have the demonstrable biological benefits of atmospheric CO2 enrichment, which are huge: 30 to 50% increases in plant productivity and a near-doubling of plant water use efficiency for a doubling of the air's CO2 content, along with suggestions of modest increases in plant constituents that may be effective in enhancing animal and human health.  On the other hand, we have the theoretical predictions of CO2-induced global warming, which is hypothesized -- rightly or wrongly -- to produce a number of catastrophic negative consequences for nearly all forms of life.

Does one of these ultimate outcomes outweigh the other?  One criterion that may help us answer this question has to do with each scenario's relative certainty or uncertainty of occurring; and on this basis, the proven biological benefits of atmospheric CO2 enrichment are clearly much more certain to occur than are the predicted negative consequences that have been associated with rising atmospheric CO2 concentrations.

Another criterion that may help us evaluate the relative merits of allowing or not allowing the air's CO2 content to continue to rise has to do with determining the relative danger of choosing one path over the other.  At first glance, this approach to the subject might seem to greatly favor curtailing CO2 emissions; for the global warming scenario has been painted by the bishops and others to be so much more horrific than the alternative, which is never even mentioned by them, presumably because they are not aware of any problem that could be caused by stabilizing the air's CO2 concentration at or slightly above its current level.  But there is such a problem.  And it is equally as great as -- or possibly even greater than -- the predicted danger of letting the air's CO2 content rise.  In addition, this danger is far more certain of occurring, unless something is done to avert it, than is the doomsday scenario on which the U.S. Catholic bishops solely focus.

The basis for this claim is described in our Editorial of 13 June 2001 (Two Crises of Unbelievable Magnitude: Can We Prevent One Without Exacerbating the Other?) where we weigh the potential danger of global warming against the potential danger of insufficient future food production.  This latter scenario has been elucidated in great detail by Idso and Idso (2000), Wallace (2000) and Tilman et al. (2001).  Briefly, it projects the human population of the globe fifty years into the future, along with global agricultural productivity; and even assuming concurrent advancements in agricultural expertise, the three studies all find that the production of food cannot possibly meet the demand for food that will occur by the year 2050 without some extraordinary measures on the part of humanity.

How important is the problem?  Tilman et al. appear to put it on the same footing as the catastrophic consequences attributed to global warming; for they say it will necessitate the expansion of agriculture onto land that currently supports a full third of all tropical and temperate forests, savannas and grasslands, noting that the destruction of that important natural habitat will lead to the extinction of untold numbers of plant and animal species.  And they ominously state that "even the best available technologies, fully deployed, cannot prevent many of the forecasted problems."  Likewise, Wallace says there can be "no greater global challenge today on which physical and social scientists can work together than the goal of producing the food required for future generations," seemingly elevating the future food production problem above anything else currently predicted or imagined.

So what extra measures could humanity take to meet this "greatest global challenge?"  This is the question Idso and Idso (2000) address, concluding that if the air's CO2 concentration is allowed to rise unimpeded by overt actions designed to curtail anthropogenic CO2 emissions, the extra plant productivity provided by the aerial fertilization effect of atmospheric CO2 enrichment will be just barely sufficient to make up for the shortfall in agricultural production that would still remain fifty years from now in spite of everything else man could possibly do to increase the global supply of food.

This, then, is the real dilemma we face: how to evaluate the relative likelihoods of the two "doomsday scenarios" that lie before us, one of which could well be alleviated by allowing the air's CO2 content to continue to rise, and one of which might be exacerbated by doing so.  The challenge as presented by the U.S. Catholic bishops falls far short of what is required to determine policy in this matter, as it only considers one of two well-documented futures that will be drastically affected by what we do or don't do about the ongoing rise in the air's CO2 content.  Hence, it clearly violates several of the principles of action derived from their study of Holy Writ, i.e., to be prudent, seek the common good, and have respect for all of God's creations.

This is not to say the bishops have knowingly mislead the world in this specific instance.  One could, for example, consider them much like Saul, who thinking he did God service, went about actually creating havoc for the followers of Christ.  Rather, the bishops' actions highlight -- primarily by default, however -- the important fact that reason and religion must be equal partners in the quest to preserve the biosphere in the face of the great challenges that confront us; for unless one knows the intricacies of what is happening in many closely related areas -- such as the facts that (1) we are confronted with an incredible future food supply crisis and (2) letting the air's CO2 content continue to rise is perhaps the only hope we have of averting the problem -- one cannot properly apply the principles enunciated by the bishops to the perceived challenge of atmospheric CO2 enrichment, which in all likelihood is actually a blessing in disguise.  Indeed, if the true workings of many such real-world phenomena are not accurately known, the application of those principles can actually end up being imprudent, inimical to the common good, and destructive of God's creations.  It is thus our hope that the U.S. Catholic bishops, having once had these facts pointed out to them, would -- like Saul of old -- be converted to a new way of thinking about this important matter.

Dr. Craig D. Idso
Dr. Keith E. Idso
Vice President