CAN SCIENCE SAVE US?

Well over ten years ago, perhaps in response to the emerging threat of AIDS -- though it could have been in regard to cancer, or almost any other medical problem -- there was a letter in the San Francisco Chronicle. In it the writer urged that the way to address the problem was for scientists to develop a panacea. The writer apparently was serious, although abysmally informed.

Unfortunately, the progress of science and technology has led to an almost slavish belief in the ability of "science" to solve all of our problems. Perhaps even more unfortunately, such a belief has been encouraged by some at least formerly respectable scientific publications. Only a year or so ago, for example, the editors of Scientific American quoted with seeming approval a reader's proposal that the way to deal with the issue of highly radioactive waste from nuclear plants -- currently planned for an underground facility at Yucca Mountain, Nevada, though still undergoing numerous legal challenges from its opponents -- was to wait a hundred years, because by then science will have figured out a solution to the problem.

The idea that science can solve all problems is arrant nonsense. There is no "cure for cancer" despite pronouncements going back at least fifty years that such a cure was "right around the corner." Moreover, there is not even a sure cure for any single kind of cancer, except perhaps for the surgical removal of certain skin cancers, if caught in time. This is because cancer, in its numerous varieties, arises from many, often interacting causes: genetic predisposition, genetic mutation caused by chemicals or radiation, viral infection, the failure of the immune system, the breakdown of body repair systems, and so on. It is the very complexity of cancer which has thus far defeated attempts to "cure" it.

Similarly, Star Trek-type teleportation or hand-held diagnostic medical probes, human travel to other planets in our own or distant stellar systems, invisibility, walking through walls or on water, personal hovercraft, all remain fantasies of active imaginations. (On the other hand, there are innumerable inventions for personal and/or recreational use which are powered by internal combustion engines: lawnmowers, weed whackers, jet skis, snowmobiles, dirt bikes, off-road vehicles, and so on. All use fossil fuel, and all serve to compound the problem of global warming.)

The question, Can science save us? and the hope that it can, have been around from well before the blurb on George Lundberg's 1961 book of that name confidently proclaimed, "The scientific method, applied to all social problems, presents our best hope of achieving the better society we all desire. A distinguished sociologist outlines the possibilities in a book of fundamental importance to us all." [That's three all's in two sentences!]

Can science save us from the increasing global warming that is due to our burning of fossil fuels? It's worth looking at some of the possible solutions.

POSSIBLE SOLUTIONS:

1. Sequestering carbon dioxide. This means taking carbon dioxide and putting it away somewhere where it cannot warm the atmosphere. One proposed way to accomplish that is the "natural" way, that is, by using terrestrial plants to draw down atmospheric carbon dioxide. Increasing the amount of terrestrial plant matter (increasing what is known as biomass) would indeed help reduce the amount carbon dioxide in the air. The planting of trees is usually the preferred method for implementing this strategy. But, on closer examination, tree planting seems only to sequester carbon for a short time, and in limited quantities. In any case, China appears to be the single major country in the world which is actually embarked on a serious reforestation effort.

The other proposed sequestration scenarios require much more active intervention. One suggestion is to put the carbon dioxide in seafloor hydrates, that is, in the same type of icy lattices in which most seafloor methane is now stored. Presumably this is technologically feasible, though what the financial and energy costs would be is another matter. At first glance, however, it seems rather foolhardy to attempt to store carbon dioxide in structures that could be vulnerable to global warming.

Another proposal is to sequester the carbon dioxide in caves underground. Exactly how this storage would be accomplished is one question, but it seems to require that the carbon dioxide be obtained from what is called a point source, that is, a single producer, rather than from the atmosphere or from the millions of vehicles that dump carbon dioxide into the air. Electrical generating plants that run on fuel oil or coal, for example, constitute point sources. Because the generation of electricity is responsible for approximately 40% of the carbon dioxide emissions produced in the United States, the idea of trapping carbon dioxide at point sources does make sense. Point sources would also exist in a hydrogen economy (see below), where the hydrogen would be obtained from methane in specific facilities designed for the purpose. As the methane was torn apart for its hydrogen, the resulting carbon dioxide would be trapped and sent underground.

But the storage of carbon dioxide in caves may be quite foolhardy. Most caves, and certainly most deep, large caves, are found in either limestone or dolomite rock. These caves exist because acidic water has dissolved these carbonate minerals. Sending carbon dioxide into such caves, where it would mix with water to produce carbonic acid, would insure that the storage chamber would eventually dissolve, allowing the remaining sequestered gas to escape its confinement.

A better suggestion would be to store the gas in rock strata a mile or so underground. Indeed, wells to test this concept are already planned for the Central Valley in California. Advocates enthusiastically note that the Valley offers enormous promise for carbon dioxide storage: "'We could potentially sequester several hundred years' worth of California's carbon dioxide there,'" notes Larry Myer, head of the scientific team researching the possibility (Wilson, 2006). But pumping huge quantities of carbon dioxide underground, even if not into caves, presents similar problems to those encountered with caves.

Carbonate minerals do dissolve in contact with carbonic acid, and the injection of carbon dioxide does turn underground water into carbonic acid. In a test performed in Texas, the underground brine (salty water), originally just slightly acidic (pH 6.5) became highly acidic (pH 3.0) and "'many, many minerals'" in addition to the carbonates dissolved, releasing potentially toxic metals and organic matter which could migrate into and contaminate fresh water aquifers (Kharaka, 2006; Kerr, 2006).

The technology to accomplish underground storage is currently under development, but the cost is prohibitive. However, the cost, as always, will be borne by consumers.

One of the few sensible proposals is to sequester the carbon dioxide as magnesite (MgCO¸3), a geologically inert rock (this comes from Wally Broecker, geochemist, oceanographer and climatologist). That at least would fully remove the carbon dioxide from the global carbon cycle. Though the details of this storage proposal may be problematic, a related but plausible approach may be to inject carbon dioxide into flood basalts (also referred to as large igneous provinces), those huge ancient outpourings of lava found in numerous parts of the world (McGrail, 2006). (The best known of these flood basalts in the United States is the Columbia River Basalt Group in Washington, Oregon, and Idaho.)

These rock formations contain large quantities of calcium, magnesium, and iron, which can be dissolved by the carbonic acid produced when the injected carbon dioxide combines with water. The calcium first reacts with the carbon dioxide to yield calcium carbonate, which then over time combines with the magnesium and iron to produce ankerite (Ca(Fe,Mg)(CO¸3)¸2), a stable carbonate mineral. If the chemical reactions proceed at a pace rapid enough, such a system of geologic sequestration would permit the storage of considerable quantities of carbon dioxide from coal-burning power plants (McGrail, 2006). This would address one significant source of carbon dioxide emissions. But, once again, the cost is likely to be quite high.

The most discussed system for getting rid of excess atmospheric carbon dioxide, however, is called iron fertilization (or ocean fertilization, which is more inclusive). It is based on the fact that phytoplankton, like terrestrial green plants, use carbon dioxide in combination with water to produce simple sugar (from which, with other nutrients, all organic compounds needed for existence and reproduction are produced). Without carbon dioxide, phytoplankton (as well as terrestrial green plants) would starve: carbon dioxide is essential for existence.

The idea behind iron fertilization is a simple one: more phytoplankton means that more carbon dioxide would be used up. For phytoplankton, living in the ocean, there is plenty of the raw materials for photosynthesis: water and carbon dioxide. But the supply of other essential nutrients is limited; these nutrients are nitrate, phosphate, and iron. The quantities of these nutrients vary from place to place, so that in any given place at any particular time, the ability of phytoplankton to grow and reproduce may be limited by whichever of these nutrients is in the shortest supply. Often the limiting nutrient is iron.

Therefore, by adding iron to the ocean, phytoplankton can be expected to bloom, that is, it can be expected to grow and reproduce to the maximum extent possible -- up until it is limited by the short supply of yet another essential nutrient. Until that happens, the phytoplankton will draw down the excess carbon dioxide in the atmosphere. As the phytoplankton bloom dies off, many of the dead organisms will fall as carbon rain to the ocean floor, and eventually be removed from the global carbon cycle. Eureka! Excess carbon dioxide problem solved! Fertilizing the ocean with iron also has the advantage of being able to pull the carbon dioxide directly from the atmosphere, and avoids the necessity of having point sources in order to be feasible.

Alas, iron fertilization is not without its own problems. To begin with, even some of its most enthusiastic proponents admit that it can only draw down 10-20% of the carbon dioxide that is being dumped into the atmosphere, and only if such fertilization is done continuously and on a large scale (Ulf Riebesell, quoted in Schiermeier, 2003).

Tests at sea do indicate that iron fertilization does cause major, short-term blooms of phytoplankton. One experiment actually increased phytoplankton some 20 to 30 times (Chisholm, 2001). But the amount of carbon that is sent to the deep is far less than predicted: in fact, only about 1% of that predicted (Dalton, 2002). This is partly due to the presence of another limiting nutrient, silica, at least in the area where the experiments were conducted, the Southern Ocean. Most of the phytoplankton there consist of diatoms, which require silica for their skeletons. Once the silica limit was reached, the bloom largely ceased (Trull, no date).

In addition, if iron fertilization is employed in tropical waters, the resulting changes in marine biological-chemical cycles produces extra nitrous oxide (N¸2O), a much more powerful greenhouse gas than carbon dioxide or even methane. It also remains in the atmosphere for much longer than methane, for about 120 years compared to methane's less than ten. The net result of iron fertilization in tropical waters, therefore, would be an actual worsening of global warming. And even outside of the tropics, where nitrous oxide production would be greatest, iron fertilization would still have similar, substantial side effects, according to the models (Jin and Gruber, 2003).

Among the side effects of iron fertilization is a sharp increase in the production of methyl bromide, which destroys the ozone layer. Side effects also include the "dramatically" enhanced production of isoprene, a chemical which generates greenhouse gases (Dalton, 2002) and is a severe and sometimes lethal respiratory irritant (Nielsen, 2001). In addition, iron fertilization, by inducing phytoplankton blooms in particular areas, would reduce the availability of limited nutrients such as nitrates and phosphates in adjacent areas. Most disconcerting, however, is the likelihood that continuing iron fertilization would result in the depletion of oxygen in the deep ocean, leading to dysoxic or anoxic conditions there (Chisholm, 2001), an outcome which would render the deep ocean sulfidic, and a threat to life both at sea and on land.

2. Space sun screens. Though it may not to have made it into print yet [oops, it now has!], surely someone will decide that the way to lessen global warming is to reduce the amount of solar radiation which hits the planet. Such screens could presumably be made of thin plastic sheeting, with light but strong structural elements, kind of like space umbrellas. But they could not be deployed over tropical or temperate areas of the Earth without serious and unpredictable consequences, both to weather and to the biosphere, and particularly to photosynthetic organisms, with repercussions up the food chain. Deployment over polar regions would make more sense, but the chill they would cause would enhance the equator-pole temperature difference, and consequently produce extreme changes in weather patterns.

An alternative idea is to send sixteen trillion (yes, you read correctly) meter (yard)-wide electronically-controlled transparent sunlight deflectors ("fliers") into space (Angel, 2006), but again, this proposal seems economically and perhaps technically unfeasible. The estimated cost is $5 trillion -- not exactly pocket change -- and the fliers themselves, with an estimated life span of 50 years (Angel, 2006; Morton, 2007), would require a colossal manufacturing effort. One commentary notes that the "US military gets through 1.5 billion bullets a year. If fliers could be mass-produced at a hundred times the rate that those bullets are, it would still take a century to produce enough of them" (Morton, 2007).

3. Re-sootifying or re-polluting the atmosphere. Actually, it's not a proposal for adding soot to the atmosphere [oops, once again: Crutzen, 2006 does suggest the injection of soot into the stratosphere, where it could block solar radiation and cool the atmosphere]. Rather the proposal is for injecting sulfur dioxide or sulfate aerosols into the atmosphere, which do indeed produce cooling. (Sulfur dioxide, a gas, rapidly combines with other constituents of the atmosphere to produce sulfate aerosols.] Undoubtedly someone will suggest this: after all, a ecocidal former US Presidential Chief-of-Staff once proposed that the answer to the destruction of the ozone layer could be for us all to use sunscreen lotion and put on sunglasses (it's too bad this won't work for other living things). Sulfur dioxide and sulfate aerosols do partially block solar radiation; that's why successful efforts to clean the air are now increasing the amount of solar radiation reaching the planet's surface. The cost: impaired respiratory function of air-breathers, including human beings, and possible damage to vegetation, including food crops, as well as possible further damage to the ozone layer.

[Postscript, 11/18/06: Indeed, this suggestion has indeed struck some folks -- including a Nobel Prize winner -- as a worthy proposal, and it is gaining proponents (Crutzen, 2006; Revkin, 2006; Kerr, 2006; Wigley, 2006), particularly after a previously favorite cockamamie idea, iron fertilization, started losing support. It apparently was first proposed in the 1980s by Wally Broecker, who decided that it would produce additional acid rain (Revkin, 2006). The suggestion was taken up again in 1997 by that proponent of many other great ideas, Edward Teller (Revkin, 2006; Kerr, 2006). One may appreciate the frustration on the part of those who really do care about the future of the planet (Teller not being notable in this regard) in the face of the intransigence of the energy companies and their political enablers toward doing anything about global warming (which would compromise their profits), but grasping at straws won't address the problem either. This "solution" is enormously expensive (25 to 50 billion dollars per year, according to the estimate of Crutzen, 2006), but even if it isn't, it has at least three extremely serious difficulties.

First, it would cause the atmosphere to become increasingly acidified (both from sulfuric and carbonic acids), with harmful consequences for living things including food crops.

Second, it would allow continuing carbon dioxide pollution of the atmosphere. This, in fact, is what it is intended to do, with sulfide or sulfate pollution counteracting the warming effects of the increasing carbon dioxide. (The proponents of this proposal, Crutzen and Wigley, do offer this approach to allow time to reduce carbon dioxide emissions, but the fossil fuel industry is likely to view such proposals simply as a means to prolong inaction.) However, a substantial portion of that carbon dioxide will remain in the atmosphere well after the last bit of fossil fuel is gone, perhaps two hundred and fifty years in our future. Because sulfur dioxide or sulfate would have to be pumped into the atmosphere at a relatively constant rate in order to avert global climate catastrophe, what would insure that we could continue to -- and continue to afford to -- engage in this practice far into the future? We should recall David Archer's cautionary statement, "A better shorthand for public discussion might be that CO2 sticks around for hundreds of years, plus 25% that sticks around forever" (Archer, 2005).

But what if we cannot afford to continue the practice of sulfur dioxide/sulfate injection, or if harmful consequences force us to stop? Abruptly (because injected sulfur dioxide or sulfate remains in the atmosphere for only a short time, a year or two at the most) we will be confronted with an escalation of global temperature much more rapid than that which we currently face.

Third, the acidification of the ocean will continue unabated -- indeed, it will proceed even more rapidly -- because carbon dioxide will enter the ocean at an accelerating rate. The carbonic acid thereby produced will destroy the carbonate skeletons of the coccolithophores, and, consequently, the coccolithophores themselves. These microscopic organisms make a major contribution to the atmosphere's oxygen, and oxygen concentrations will fall. Undoubtedly numerous other marine organisms, including corals, will expire as ocean acidity increases. Will we destroy other marine photosynthesizers besides the coccolithophores, further cutting oxygen input to the atmosphere? Will the oceans become anoxic? Will the changing marine conditions allow the sulfate-reducers to become the dominant microbes in the oceans, and dump deadly hydrogen sulfide into the oceans and atmosphere? These are extremely complex and most serious questions, which the advocates of sulfur dioxide/sulfate injection have not addressed.

And there is a final question, which simply cannot be answered in advance: What if the process of ocean acidification provides the necessary ecological conditions for some now unknown marine organism (or group of organisms) with potentially lethal abilities to thrive? After all, we have identified fewer than a tenth of a percent of the microbes in the sea, and we certainly have little understanding of what many of those which we have identified actually do. What of the other 99.9%? By upsetting the acidity balance of the oceans, we will most assuredly be creating conditions in which presently unknown organisms will flourish, perhaps much to our great future unhappiness.]

Playing ecological Whack-a-mole: At county fairs all over America, along with other standards such as target shooting, hurling baseballs at milk bottles, and trying to pitch dimes into saucers, is the perennial favorite, Whack-a-mole. Whack-a-mole requires that the player use a soft-headed mallet to hit, in rapid succession, a series of mole-like figures which pop up at random from various holes in the gameboard. A prize goes to the player who accurately hits each mole in the proper order. Needless to say, not many players win prizes. Whack-a-mole seems an appropriate metaphor for many of our ecological rescue endeavors. Here are two examples: Ecological Whack-a-mole, I: In the early 1950s, the United States parachuted some three thousand cats into a remote region of Malaysia, in the northern part of the island of Borneo. The cats, fortunately, did not have their own individual parachute harnesses, but were in cages that sprang open on contact with the ground. The cats were needed to end (if they could) a local ecological crisis that began with a well-intentioned World Health Organization effort to suppress malarial mosquitoes. To kill off the mosquitoes, planes sprayed DDT (a pesticide now banned because of its toxicity, and especially for its effects on bird shells, leading to major declines in bird populations). The DDT killed off the mosquitoes (at least temporarily), but the pesticide also accumulated in the local roaches, which did survive. The roaches were a dietary staple of some small local lizards (geckos), which also consumed large numbers of caterpillars. The DDT in the roaches affected the mobility of the lizards, which were slowed sufficiently to make them easy prey for the local cats. With the demise of the lizards, the caterpillars proliferated. One of their favorite foods was the thatch used by the local human population for roofing material for their huts. The ensuing caterpillar proliferation destroyed people's roofs. Meanwhile, the cats, having consumed the lizards, died from DDT poisoning. With the demise of the cats, the rat population exploded, and with the rats came bubonic plague. To stop the outbreak of plague, the rats had to be killed. Hence the parachuting in of the cats (story from Fagerlund, 2003). Ecological Whack-a-mole, II: Another story of unintended outcomes also begins with DDT (which, although a now-banned toxic villain, is certainly not the root of all our environmental missteps). Off the southern California coast are a number of large islands, the Channel Islands, of which Santa Catalina is undoubtedly the best known. For years, many of these islands have been used as rangeland to graze cattle and sheep. From the mid-40s through the early 60s, millions of pounds of DDT and the carcinogen PCB (now also banned) were dumped as waste into the Pacific Ocean near the Channel Islands. The DDT, which is still present, was ingested by fish. The fish, in turn, were consumed by seals and gulls. Working its way up the food chain, DDT-contaminated fish, gulls, and dead seals were consumed by the Islands' native bald eagles. As elsewhere, the DDT had a devastating weakening effect on bird eggshells. The bald eagles were wiped out. Santa Cruz Island, one of the Channel Islands, had been used for sheep and, to a lesser extent, cattle ranching, for years. With this entire island now held by the Nature Conservancy and the National Park service, attempts are underway to restore the original ecological balance. The cattle are gone; the remaining sheep have been removed. But thousands of wild pigs still roam the island. The pigs, whose reproduction gives rise to many tasty piglets, attracted the attention of a mainland-based predator, the golden eagle. Lacking bald eagles, the golden eagles have become the island's top aerial predator. And they have had quite ruinous effect on the island's other top, but non-aerial predator, the Channel Islands fox. Golden eagles apparently enjoy eating fox kits as much as they enjoy piglets. In just seven years, the fox population plummeted from about 2000 to around 70. The attempt to restore the former ecological balance has required several new programs: one for breeding foxes, another to help bring back the bald eagle, and, through competition with the bald eagles, persuading the golden eagles to depart for easier meals elsewhere. As of a 2002 report, however, "Life on this island is completely out of whack." According to wildlife biologist Erik Aschehoug, "It is all so incredibly interconnected" (story from McCabe, 2002). {Postscript, summer 2005: Things are looking better for the island foxes. This spring, some 52 fox kits were born in the wild, and they will be supplemented by another 38 born in a captive breeding program. But saving the foxes has required yet another ecological intervention, killing feral pigs. ] Ecological interventions can clearly have consequences well beyond what is intended or expected. Sometimes called blowback -- possibly in reference to the flicking of cigarette ashes out the car window by heedless drivers, ashes which then hit backseat passengers in the eye -- unintended consequences dog many ecological interventions. In the cases cited above, the consequences occurred relatively rapidly after the intervention, and because most of the organisms involved are of relatively large size (the exception is the plague bacterium), those consequences were quickly identifiable. In addition, the solutions -- imposed from outside the affected area -- were straightforward, even if unexpectedly bizarre (as with the para-cats) or complex. Most of these attributes do not characterize the coming climate catastrophes. There will be no areas that are outside of those affected, because the entire planet will be subject to the changed conditions. The interacting organisms will include all 10 million or so species of our world. While microorganisms will be major participants in the crises, most of them will probably escape extinction. The same cannot be said for larger organisms, many of which will disappear forever. And not only will organisms be affected, but the chemistry of atmosphere, ocean, and soils as well. Global ecological interventions such as iron fertilization, sunscreens, and re-sootifying the atmosphere will certainly require additional, now unforeseeable interventions ("global whack-a-mole"), and will take the Earth and all its inhabitants in directions so removed from current natural conditions that they simply cannot be predicted.

4. Replacing fossil fuels.

Ethanol. The use of ethanol (alcohol derived from crops such as corn or sugar cane) as a substitute for, or at least a supplement to, gasoline has been widely touted as a partial solution to the energy problems of the United States and the world. And indeed, such use would provide some minimal relief from the dependence of many advanced industrial countries on the oil produced in the Middle East, Africa, Venezuela, and Indonesia. But though the use of ethanol may address various international relations and balance of payment issues, it will not solve the greenhouse gas problem, and, in fact, will compound it.

In theory, ethanol ought to help address the carbon dioxide emissions problem. The burning of ethanol does indeed involve the dumping of carbon dioxide into the atmosphere:

C¸2H¸5OH + 3O¸2 Æ 2CO¸2 + 3H¸2O

(ethanol) + (oxygen) (yields) (carbon dioxide) + (water)

But advocates note that the burning is merely releasing carbon dioxide which originally came from the atmosphere and has been used by the crops for growth. If the process were 100% efficient, the same amount of carbon dioxide would be released as had been absorbed by the crops during the growing season. But it is not: the production of the crops used to produce ethanol relies on heavy machinery which use gasoline, not ethanol.

Highly industrialized countries, in addition to their industrial production of manufactured goods, also have highly industrialized agriculture, which is totally dependent on industrial methods for soil preparation, planting, cultivation, irrigation, fertilization, harvesting, crop processing, ethanol storage, and distribution. These operations consume huge quantities of energy, in the form of gasoline and other fossil fuels. The use of ethanol, therefore, actually adds to the greenhouse gas problem rather than helping to mitigate it. Despite its reputation as a "clean" fuel (and it certainly is cleaner than gasoline in some regards, though not in others), the burning of ethanol compounds the problem.

In fact, the very "sustainability" of ethanol production, because it comes from "renewable" plant crops, means that even more carbon dioxide will be dumped into the atmosphere than just via the burning of gasoline or other fossil fuel alone. In the United States, it requires almost a gallon of gasoline (or roughly equivalent fossil fuel) to produce and transport a gallon of corn-derived ethanol. More specifically, the input of about six energy units of fossil fuel yields an output of about seven energy units of ethanol biofuel. (By contrast, an energy input of one unit into petroleum production yields well over ten energy units of gasoline. It is this enormous efficiency -- in cost versus benefit terms -- which has caused fossil fuels to become the heroin of industrial economies, and is why withdrawal will be so painful.) Ethanol, moreover, cannot be transported by pipeline because it is too corrosive, and must be moved by truck (Crenson, 2007).

Deriving ethanol from corn, despite its enthusiastic promotion by US agricultural interests, is a particularly inefficient use of energy resources (Cleveland, 2006; Farrell, 2006; Hagens, 2006; Kaufman, 2006). Using high cellulose vegetable matter such as the plant residues from sugar cane (as Brazil does), or switchgrass, makes more sense. (Whereas the total greenhouse gas output from corn-derived ethanol can range from 70% to 100% of that of gasoline, the total greenhouse gas output of ethanol made from cellulosic plants like sugar cane or switchgrass ranges from 30% to 70%: Lau, 2006.) Yet producing ethanol from high cellulose plant matter is more than twice as expensive as making it from corn (Crenson, 2007).

Why then does the US federal government require the inclusion of ethanol in gasoline? Basically, this is a payoff to agribusiness and associated energy interests for their political support, though it makes virtually no economic sense whatever. (The current federal subsidy for ethanol amounts to about 51 cents per gallon: Crenson, 2007.)

But even more energy efficient plant sources than corn cannot possibly provide for more than a small percentage of future energy needs, because we simply cannot convert all, or most, of our agricultural land to the production of "food" for automobiles. One estimate, for example, is that a car that travels some 20,000 kilometers (about 12,000 miles) per year would require "an agricultural production seven times the dietary requirement for one person" (Connor and Mínguez, 2006). Another estimate suggests an even higher equivalency cost: "The grain it takes to fill a 25-gallon tank with ethanol just once will feed one person for a whole year" (Brown, 2007). Converting our entire corn crop to fuel for automobiles would only satisfy about a fifth of their needs.

Additionally, ethanol delivers only about 70% of the energy of gasoline, and cannot be used as an aircraft fuel. Current internal combustion engines cannot efficiently run solely on ethanol. Cars need special equipment to run on fuel that is more than 10% ethanol. Lacking proper modifications, automobile and other internal combustion engines running over 15% ethanol will be destroyed by corrosion. Even "flex fuel" cars that can run primarily on ethanol still require at least 15% gasoline (Crenson, 2007). Consequently, although ethanol is typically described as an "alternative" fuel, it is not generally conceived as a replacement fuel for gasoline. Rather, therefore, it is most properly considered as a supplementary fuel, with the potential to provide a small addition to fossil fuels, but at the cost of further extending the era of the carbon dioxide-emitting internal combustion engine.

The current transportation-related ethanol produced in the United States derives from more than 3 1/2 million hectares (8 1/2 million acres) of prime cropland (DeLuca, 2006). With the completion in the near future of many ethanol producing distilleries that are now projected or under construction, the demand for corn is expected to skyrocket. Because the cost of wheat and rice will rise in response (as consumers switch from more expensive corn to other grains), world grain prices will also increase, possibly to their highest in history, leading to quite serious economic and political consequences globally. These grain price increases and their economic and political repercussions are not matters for a far-off future; they are projected to begin next year, 2008, as the numerous new corn distilleries come online (Brown, 2007). In addition, of course, because many food animals consume corn and other grains, the price of meat will also rise.

But what of countries like Brazil, which has an extensive program to supplement the use of gasoline with that of ethanol (though Brazil's program depends largely on ethanol derived from the more efficient sugar cane, rather than that derived from corn)? Again, Brazil is addressing the problem of importing foreign oil, and reducing its dependence on gasoline, but carbon dioxide continues to be dumped. As its economy continues to expand, Brazil, like all other countries that depend on carbon fuels as their energy base, will increase its contribution to anthropogenic global warming.

The "hydrogen economy." This has been much hyped, and enjoys a good press, which usually notes that hydrogen is a clean fuel. And indeed it is: burning hydrogen produces water (2H¸2 + O¸2 Æ 2H¸2O). But producing the necessary hydrogen is not necessarily a clean process at all.

One way to obtain hydrogen is by stripping it from . . . methane! Each molecule of methane contains four atoms of hydrogen for every atom of carbon (that's why its chemical formula is CH¸4). Certainly that's lots of hydrogen. But the residue is carbon, typically released as carbon dioxide. Oops! That's not very clean, is it? In addition, the cost of the process is prohibitive for the quantities of hydrogen needed, at least at present.

Another way to get hydrogen is via the electrolysis of water. In this process, electricity is run through water (H¸2O), tearing the water molecules apart for their hydrogen. Clean, but even more expensive than getting hydrogen from methane.

A new process offers the possibility of extracting hydrogen from water without resorting to electrolysis. By mixing water with organosilane (an "organic liquid"), and then adding a small piece of the metal rhenium, hydrogen can be produced at room temperature. Unfortunately, organosilane is expensive, and expensive enough prohibit large-scale hydrogen production by this method (Cunningham, 2005, reporting on the work of M. Abu-Omar).

There is a fourth possibility, which actually may make sense: obtaining hydrogen from "bugs," as microorganisms are frequently known to biologists and paleontologists. The idea is to engineer bugs to dump hydrogen as a waste product. Indeed, some visionary folks are already working on this, and have succeeded in inducing some microorganisms to emit hydrogen, presumably via the breakdown of water. Feasibility on a large scale? Cost? Timeline for large-scale development? I have no idea.

But even if the difficulties with producing hydrogen are resolved, and costs are reduced, hydrogen still presents problems that fuels such as gasoline do not. It must be chilled to quite low temperatures, into its liquid state, for storage. It must be kept in special, pressurized containers to maintain that liquid state and to minimize leakage. Leakage is a major problem in any case, and the transport of hydrogen is far less efficient (only about a tenth so) than that of gasoline. Hydrogen is simply far from adequate as a substitute for fossil fuels, and far more costly.

The cases of ethanol and hydrogen (at least the relatively cheap hydrogen derived from natural gas) -- "clean" fuels often depicted as panaceas for our increasing energy needs and the coming depletion of petroleum -- emphatically indicate that purported solutions frequently do not address basic, underlying problems. Hype, frequently emanating from those with economic interests in particular technologies, cannot hope to solve the most serious economic issues and political decisions with which anthropogenic global warming confronts us.

Unlike hydrogen, which can be used to power personal vehicles and small-sized mobile applications, other replacements for fossil fuels cannot themselves be directly incorporated in small engines. Instead, these other replacements must be used to generate electricity, which would then be stored in batteries for use by electric motors. These possible solutions include:

Nuclear fission. Already in extensive use in nuclear power plants. Its limitations, which have prevented any new nuclear power plants from being built for almost thirty years in the United States, are that it is dirty (producing both low level and high level radioactive waste) and dangerous. As the first and only American high level nuclear waste repository at Yucca Mountain, Nevada, is still years away from opening -- if it ever does -- the basic problem of the disposal of radioactive waste from nuclear fission power plants has yet to be solved. In addition, there is the matter of nuclear power plant safety. Nuclear accidents do happen, as shown by the experiences of Chernobyl in the Ukraine (the surrounding urban area and countryside are still radioactive and abandoned) and Three Mile Island in Pennsylvania.

As someone who taught a mere mile away from the Three Mile Island nuclear power plant, and listened to the constant stream of disinformation put out during that March, 1979, crisis, I still do not know why the containment vessel (which held the nuclear reactor itself) actually survived. I'm not sure that anyone else does, either. But if it had failed, the molten radioactive material would have melted its way through the underlying rock until it hit water. At that point it would have created superheated steam, which would have blasted both water and uranium fuel into the atmosphere.

This scenario, called the China Syndrome, was made famous by the movie of that name. The name derives from the purported ability of nuclear fuel to breach containment and melt all the way to China, because there is nothing that would be able to stop it. All rock in its path would be melted by its enormous heat, and its weight -- greater than all other natural elements -- would carry it ever downward. (Actually, it could only melt to the center of the Earth, because its weight would keep it there. But well before that, it would make explosive contact with intervening subsurface water, which in the case of Three Mile Island, being in the middle of the Susquehanna River, was quite close to ground level.) The movie was fiction; the possibility it portrayed -- a meltdown and breach of containment -- was not. The total eventual costs of the Chernobyl nuclear accident are projected to run in the hundreds of billions of dollars -- vastly more than the original cost of building that nuclear power plant.

Aside from general safety and waste disposal issues, there is another major problem with nuclear fission. Despite our having been told by the nuclear industry in the 1950s that nuclear power would result in "power too cheap to meter," nuclear fuel -- uranium -- is in surprisingly short supply. To produce the same amount of power that the global human population consumes today entirely with nuclear reactors, we would exhaust the supply of uranium needed to run those plants in just 6 to 30 years (Hoffert, 2002)! At best, therefore, nuclear fission can only help us address our ever-increasing power needs on a temporary basis. With nuclear fission power plants each costing well over a billion dollars to build, and with lifetimes of just 30 to 40 years, the prospect of limited fuel will certainly cap the number of such plants that will ever be built (Hoffert, 2002). Those who foresee a great renaissance for nuclear power in the near future may be right in the short term, but eventually these power plants will stand as idle as automobiles that run on gasoline, ruined relics of the industrial age.

Nuclear fusion. Once upon a time it seemed that nuclear fusion was the solution to our future energy problems. It seemed clean (producing helium from hydrogen) and non-radioactive. Things turned out to be somewhat more complicated.

First, the projected fuel for fusion is not typically simple hydrogen, that is, hydrogen with a single particle in its nucleus, a proton. Instead, it is one of the other two isotopes of hydrogen, either deuterium (which has a neutron in the nucleus in addition to the proton) or tritium (which has two neutrons in the nucleus in addition to the proton). Tritium is radioactive, although only moderately so.

But each of these potential fuels produces lots of high-energy neutrons during fusion, and these quickly degrade reactor vessels, rendering them unusable. Alternatively, Helium-3 (^3He: helium with two protons and one neutron in its nucleus) is a much better fusion fuel because it generates no high-energy neutrons. (Most helium is Helium-4, ^4He, with two protons and two neutrons. This is not a fusion fuel, but rather the end product of the fusion process.) Unfortunately, Helium-3 virtually non-existent on Earth.

However, solar wind particles deposit Helium-3 on the Moon, where there may be a million metric tons (a metric ton = 1.1 imperial ton) of it in the top 2 meters of the lunar surface, according to University of Wisconsin engineering professor Gerald Kulcinski. And just some 30 metric tons could generate energy equivalent to the annual United States' electrical use. If global energy consumption is roughly five times that of the United States, 150 metric tons of helium-3 would be all we need to take care of our annual planetary needs.

Sound like going to the Moon and shoveling Helium-3 into spaceships is a simple solution to our energy problem? Let's see. The surface of the Moon is about 40 million km2 (15.4 million mi2). If the million metric tons of Helium-3 is evenly distributed, that's a metric ton every 40 km2 (15.4 mi2). To obtain 150 metric tons, therefore, we'd have to turn over about 6000 km2 (or about 2300 mi2) worth of moon surface. That's equivalent to excavating a 1.5 km ( one mile) wide trench from New York to Salt Lake City, to a depth of 2 meters (6 1/2 feet) . . . each year.

And that's just the unprocessed stuff on the surface, containing the Helium-3. To ship that back home would be impossible; the Helium-3 would have to be extracted first. That would require a Helium-3 extraction plant. So we'd have to send up mining equipment, processing equipment, and rockets in which to carry the helium back. At current costs, it's a million bucks to ship just a pound of fuel to the Moon. Likely, such an endeavor would greatly exceed our budget.

And, of course, this assumes that we can actually use the Helium-3 when it arrives. We can't: despite billions of dollars already spent on nuclear fusion, and billions more scheduled, we do not have a practical, large-scale fusion system. Nor we know when -- or if -- fusion is practical. If it is practical, it will likely require the use of both deuterium and tritium, and lies at least several decades in our future. Even optimistic projections indicate that the earliest large-scale fusion reactors are not expected to be operational before 2050.

Wind, solar, tidal, and geothermally-generated electrical power. All of these seem to have some potential for helping solve the energy problem, but probably none is without some drawback, even if it is minimal. Windmills increase the wind at ground level, causing drying of the land beneath them. Geothermal power stations can cause earthquakes, of generally small magnitude. And so on.

Nevertheless, these energy technologies, for the most part, seem pollution-free, and are most likely at least partial solutions to the problem of replacing fossil fuels. They need to be better funded.

5. Leaving home. There are some who think that the solution to our problems is to abandon this planet and get a fresh start elsewhere.

But where would we go?

To orbiting space cities? Prohibitively expensive to build. Even maintaining the International Space Station, with its handful of occupants, is enormously expensive and subject to unexpected interruptions. The 2 1/2 year absence of the US Space Shuttle, due to the Challenger accident, left the space station with a slender life-line indeed. Additional difficulties now have grounded the Shuttle until they are resolved.

To the Moon? Let's see: No air, no oxygen, no water except possibly frozen in craters near the poles. Temperatures ranging from roughly 100°C (the boiling point of water, 212°F) during the day to 100°C below (about ­150°F) at night. Agriculture as well as most living would have to be conducted indoors, in vacuum-proof buildings. Horrendously expensive.

To our neighboring planets? The surface of Venus is vastly hotter than the daytime Moon, hot enough to melt lead. Obviously, there's no water on its surface or anywhere close to it. No oxygen is in its atmosphere, but sulfuric acid is. Atmospheric pressure is tens of times greater than Earth's.

Mars? Mars is pretty cold, although daytime temperatures at the equator occasionally get above freezing, though not by much. There's little oxygen in its atmosphere -- certainly not enough to be breathable -- and it never rains. Atmospheric pressure is much lower than Earth's, so space suits would be required. This low atmospheric pressure also means that liquid water cannot remain on its surface: it would be rapidly vaporized. But there is probably lots of water in ice, not far below the surface.

Solar radiation is vastly less than Earth's, so an alternative energy system would be required. Sorry, no fossil fuels or other carbon fuels: life probably hasn't existed there, and if it did, it didn't exist in the lush quantities that it did and does on Earth. Fuel and oxygen would presumably have to be imported . . . from Earth. As with space cities or the Moon, migrants from Earth would have to bring along everything they needed to survive in completely enclosed, artificial environments.

And that's basically it for our solar system. All the other options are even more inhospitable. Not one of the possible destinations within the solar system holds the prospect of accommodating more than several dozen, or, at most, a few hundred refugees from Earth, and all at a quite staggering cost. The cost of relocating outside our solar system would be even more prohibitive:

Planets circling other stars? To reach the nearest star (other than the Sun), it would take thousands of years, using chemical fuels. Nuclear fuels, ionic propulsion, solar sails are all possibilities, but would require decades of development. Distances are prohibitive, however. The closest star other than our sun is more than four light years away. A light year is the distance light travels in a year, and because light travels very, very fast -- 300,000 km (186,000 miles) per second -- it covers a lot of distance in a short time. In a year, it travels almost 10 trillion kilometers (about 6 trillion miles). The nearest star, therefore, is more than 40 trillion kilometers (24 trillion miles) away. That's 40,000,000,000,000 kilometers, or 24,000,000,000,000 miles. At the speed commercial jets move, it would only take about 10 million years to get there. Fortunately, space craft can go much faster, so that using current standard propulsion systems at standard space craft speeds would shorten the trip to somewhere around 500,000 years.

Getting a sense of scale When dreamers think of escaping Earth for permanent residence on other planets (or the Moon), they tend to employ notions of size and distance derived from our home planet. The famous pictures of men walking on the Moon, for example, clearly show that the Moon is a big place, just as the meanderings of our Mars rovers reveal that Mars has expansive vistas. Even though both the Moon and Mars are smaller than Earth (the Moon about 1/4 Earth's diameter and consequently only 1/64 our planet's surface area, and Mars about 1/2 Earth's diameter and 1/8 our surface area), these places are certainly large by human standards and require motorized vehicles for transporting people any significant distance. But the spaciousness of their surfaces may convey a false impression of their true sizes and distances, and the immense size of "outer" space, both within our solar system and without. Such a false impression can give rise to fantasies about how easy it would be to reach and colonize other worlds. In the interest of injecting some realism into the discussion, therefore, the following relative scale is offered: Start by thinking of Earth being about the size of one of those little silver spheres on the ball-headed straight pins that all too frequently are concealed in new men's shirts. The heads of these pins are about two millimeters (about 0.09 inches, or close to 1/12 inch) in diameter. On such a scale, the Moon would be about the size of a rather puny poppy seed, and at a distance of about 6.5 centimeters (some 2 1/2 inches). Mars would be half our size (about one millimeter or 1/25ths of an inch, perhaps the size of the ball in a ball-point pen, or a mustard seed), and about 12.5 meters (41 feet) away. The farthest familiar planet (now considered a dwarf planet) in our solar system is Pluto, which in this comparison would be an even smaller poppy seed than the Moon, and at an average distance (though it has a highly elliptical orbit) of about 1200 meters (2/3 of a mile) from the Sun. The Sun itself would be about the size of a basketball (some 24 centimeters/9.5 inches in diameter, and at a distance of roughly 25 meters (82 feet; about the distance between the backboards on a basketball court). Now ruminate on that a bit: our Sun the size of a basketball, and our home planet the relative size of a round pinhead, almost a basketball court's distance away. (The reader might wish to actually set up such a Earth-Moon-Sun model system, and contemplate the vastness of space. It certainly is instructive.) OK, how far would the next nearest star (excluding our Sun) be in this model? About 6750 kilometers (more than four thousand miles) away. That's roughly the distance between Beijing and Stockholm, or between Rome and Ottawa, Canada. Sure, that star may -- or may not -- have some pinhead, mustard and poppy seed-sized -- and even larger-sized -- planets (though stars in three star systems, such as that of our nearest star, are presumed only rarely to have planets), but it's damn far away. In addition, this nearest star, Proxima Centauri, would be slightly smaller than a ping-pong ball, though one of its companions, Alpha Centauri, would be somewhat larger than our basketball-sized model Sun. Other stars, of course, are at roughly similar distances in our part of the Milky Way galaxy. Our galaxy, incidentally, contains a minimum of hundreds of billions of stars, and there are an estimated 40 to 50 billion galaxies in the Universe. It should be re-emphasized that all of these numbers are only approximations, but the realities they reveal about our place in the cosmos ought to be humbling.

But even if we could muscle up a space craft to go 10% of the speed of light (which presumably would require a long period of acceleration, and at the end of the voyage, an equally long period of deceleration). And let's suppose there was a known habitable planet some 20 light years away (probably highly unlikely). Just the "warp speed" portion of the trip would take 200 years. The crew would have to be in hibernation, or deep freeze, technologies we haven't developed yet -- and may never.

There are lots of other in-flight problems. Forget the salt (or something equally indispensable)? Sorry, folks are out of luck. Need to do repairs? Better have the tools, the expertise, and all the possibly necessary spare parts. Find that the supposedly habitable planet that was the destination isn't actually habitable at all? Back in the space craft for another 200 years: better luck next time.

Even the matter of habitability isn't clear. One of these days in the near future, we'll be able to determine (by spectroscopic analysis) whether planets in nearby stellar systems have atmospheres which contain oxygen. Oxygen in the atmosphere is a sure sign of active oxygenic (oxygen-producing) photosynthesis. So the planet would certainly have plant-like organisms similar to phytoplankton and/or terrestrial green plants. But what else would such a planet contain? What, that is, in the way of biologically-transmitted diseases (similar to those transmitted by viruses and bacteria here on Earth), or of parasites, or of predators?

And if the voyagers meet with intelligent life? Here's the response of Geoff Marcy, the astronomer who discovered the first extrasolar planets (planets which orbit other stars), and who has discovered more extrasolar planets than any other astronomer, when asked, "Is civilization prepared to encounter life beyond Earth?"

"We humans seem barely prepared to coexist with the life we have right here. No, we are not prepared to encounter extraterrestrial life -- just ask our terrestrial friends, the innumerable species who struggle against extinction.

"I hope we can soon begin to view our tiny Earth as the marvelous cosmic oasis that it is" (Schomaker, 2003).

Considering the colossal expense, the enormous risks, the great uncertainty of a successful outcome, and the tiny number of human beings who would be able to fit into the cramped quarters of a space craft making such a journey, it's probably safer to take one's chances right here on Earth.

There is one other "off-world" suggestion. That is that we find an advanced extraterrestrial civilization and ask the beings there how to solve our problems. Some of those who support the SETI (Search for ExtraTerrestrial Intelligence) project do so for this reason. So let's suppose that we do find such an advanced extraterrestrial civilization about 100 light years away (a colossally improbable likelihood). Interstellar communication can only proceed at the speed of light. So getting any answers would necessitate 100 years for the inquiry, and 100 years for the reply (which could be, Sorry, we've never encountered a problem like that). In 200 years, we will be fully in the midst of the climate crisis we are now creating, and most of the fossil fuels which will have caused it will be long gone. Frankly, such hopes on the part of certain SETI proponents should remind one of the moai (statues) on Easter Island, gazing forlornly out on an empty sea, longing for contact with other intelligent beings, and, perhaps, for rescue.

SUSTAINABILITY:

The term "sustainable" appears sufficiently often in the news these days, and usually without adequate explanation, that its meaning may be lost in the background media noise. The word, typically found in an environmentalist context, deserves far greater attention than it is accorded. It not only labels certain activities as sustainable, meaning that they are designed to survive over the long haul, but it also implies that other practices are not sustainable, and that they cannot continue as they have for the indefinite future. The term is applied to energy, agriculture, large-scale fishing, forestry, and the exploitation of natural resources.

These "unsustainability" of these activities is worth careful consideration. It means that we continue our current ways only at our peril. If we continue to overfish the world's oceans, fish harvests will shrink to minimal sizes. Already, most of the world's great fishing areas are extremely overfished. In some cases, fishing for particular species has been restricted, prohibited or simply abandoned because of low yields. In others, the continual fishing for the largest individuals is resulting in a decline of the species' average size. Techniques like the use of explosives not only kill the target fish, but all others in the area, and the corals which are the fish's habitat. Bottom-trawling fishing boats tear up the seafloor and destroy the creatures that live in and on the sediment surface, in addition to netting the fish they are actually after. At the same time, commercial fishing boats become ever larger, some with nets over a hundred and thirty kilometers (eighty miles) in length.

Clearly, these fishing practices are unsustainable. Eventually they will result in the severe depletion of usable fishing stocks all over the world, and that "eventually" is not very far in our future, perhaps within a decade or two. While this depletion is, for the most part, not due to global warming (though some is, and much more will be in the future), a similar lack of sustainability characterizes virtually all of our major economic activities. We have a non-sustainable energy system, based on non-renewable fossil fuels, non-sustainable industrialized agriculture, non-sustainable harvesting of forests, and are rapidly using up many non-renewable resources. The impending shortages will manifest themselves in increasing frequency and with growing economic impact as we move further into the twenty-first century. In addition, commodities in short supply will become eminent targets for market manipulators and economic predators, of whom there appear to be no shortage.

It is this kind of non-sustainable economy that filmmaker Luc Jacquet (March of the Penguins; in the original French, La Marche de l'Empereur) is talking about when he says, in reference to the 50% reduction in the number of Emperor penguins in the past 50 years (due to less sea ice around Antarctica, and less krill, an important link in the penguins' food chain):

"It's kind of crazy when you think of it, that this place that is so far-removed from civilization, that we're still having a destructive effect upon it."

"If you want my opinion, I'm not very optimistic about the way the world is heading. We have the expertise to understand the mechanics of the world's ecology, but the way society is functioning runs counter to the proper functioning of the ecology."

"So introducing a sustainable system would turn our whole system on its head. It would be a revolution. I think there will be other catastrophes before change occurs."

The message is simple: we cannot sustain our present way of life.

THE WEB OF LIFE:

"...it is but well to be on friendly terms with all the inmates [inhabitants] of the place one lodges in." Melville, Moby Dick, Chapter I

If the human population were suddenly transported back in time to the late Paleozoic, more than 250 million years ago, most of it would starve to death. Why? Because the vegetation of the time consisted of conifers, cycads, fern trees, and ferns, which by and large we don't eat. Paleozoic vegetation cannot be properly and efficiently processed by our digestive systems. Instead, we require the produce of flowering plants -- vegetables, fruits, and grains -- or those animals which eat them. Back in the Paleozoic these plants did not exist.

To be even more specific, most of the human population depends primarily on grains: rice, wheat, and corn. (Other important staples include sorghum, potato, yams, taro root, and manioc, none of which are grasses.) Rice, wheat, and corn are all grasses, which first evolved only about 60 million years ago, and only achieved prominence about 40 million years ago. So we are mostly dependent on grasses, which also furnish most of the food for the animals we consume: pigs, cattle, and sheep.

The ascendancy of grasses to their important place among the terrestrial flora has been attributed by some scientists to the slow decline of atmospheric carbon dioxide over the past 50 million years or so. The particular system of photosynthesis employed by grasses (known as the C4 pathway) apparently operates more efficiently than that (the C3 pathway) used by other green plants in lower carbon dioxide conditions (Pagani, 2005). [Indeed, it may be that the evolution of grasses, with their greater efficiency in carbon dioxide uptake, is responsible for the glaciation of Antarctica, which began some 34 million years ago, and the even deeper cold of the Ice Age, which has characterized the planet's climate for the past 2.4 million years.] As carbon dioxide levels increase, therefore, we can expect that grasses may lose some of their important position in the global flora to plants that operate more efficiently at higher carbon dioxide levels (above 500 ppmv: Pagani, 2005).

In addition, global warming itself may take its toll on the world's most important single crop: rice. Experimental evidence indicates that for every 1°C (1.8°F) increase in nighttime temperatures, rice biomass yield falls by 10% (Peng, 2004). But nighttime temperatures have already increased that much, just between 1979 and 2003. While daytime temperatures (daily maximums) increased by over 0.33°C (0.6°F) during that time period, nighttime temperatures (daily minimums) increased 1.1°C (2°F: Fountain, 2004). Thus further warming, especially nighttime warming, could significantly hurt future rice yields.

When we hear the expression "the web of life," it is generally in regard to other creatures. A television natural science program, for example, may invoke the concept of the web of life in discussing the plants, herbivorous insects, carnivorous insects, spiders, and birds in our backyards, fields, or vacant urban lots. The web of life is a simple metaphor to describe the complex interactions among these creatures.

But we too are part of a web of life, in which other organisms play important, even essential, roles in our survival. In advanced industrial societies, few go without food, but famine -- often caused by the death of crops due to drought -- is all too common in many other parts of the world. And drought is not the only cause of famine, as the Irish know from the great potato famine of the 1840s and 50s, when more than a million people, more than a tenth of the Irish population at the time, perished because of a disease which attacked potato plants.

We depend on other organisms not only for food, but for much of our clothing, carbon fuels (wood, peat, other vegetation) including fossil fuels (largely produced by organisms from long ago), and indeed for the oxygen in the air we breathe and even for some of the clouds which bring us rain. Organisms both well known (as potatoes and cows) and poorly known (root fungi, phytoplankton, giant larvaceans, intestinal microbes) contribute to our well-being. Undoubtedly there are others that we know little of which play important roles in our welfare.

In certain medical and population studies, the term "cohort" is often used. It refers to a group of people who share a common experience within a specified period of time. The "baby-boomers," that is, those born within a decade or so after World War II, constitute a particular kind of cohort (in this case, a "birth cohort"), for example. Caucasian males over the age of 50 who have been diagnosed with diabetes, would constitute another (here, a cohort of diseased persons).

As human beings, we are part of a vast ecological cohort of organisms, of those organisms which arose under generally similar conditions to those under which we also evolved. Although many contemporary organisms arose under somewhat different, earlier conditions, they have survived (and sometimes thrived) because today's conditions remain sufficiently hospitable to their well-being. If, due to our own activities, member after member of our own ecological cohort vanish into biological history, what can we reasonably expect for ourselves?

Humankind may indeed create its own destiny, but not under conditions chosen by itself. These conditions are the constraints under which we evolved, and under which our foodstuffs also evolved. They are the fixed realities of our lives. If we alter them, as we now beginning to do, we place ourselves outside of the natural realities which shaped our species' coming into existence and its spread over most of the surface of the Earth. As numerous scientists have pointed out, with our profligate use of fossil fuels, we are embarking on a huge, uncontrolled, and irreversible experiment with our only home.

In conclusion,
it is essential to recognize that much of the current public debate about global warming, including its causes, consequences, and possible solutions, has very little to do with science. Instead, it has a great deal to do with fundamental economic, social, and political matters, and how they are to be addressed. These are basic public policy issues, and, as with many public policy matters, individual, corporate, and general interests play a role. Certainly the current official position of the United States' government, which is to deny the existence of, the human cause of (Kintisch, 2005), and the dire likely economic, biological, and social consequences of global warming, is not based on science. Nor is the statement, "Global warming is the greatest hoax ever perpetrated on the people of the United States," uttered by the immediate past chair of the US Senate Environment and Public Works Committee (a man who has received over $10 million in campaign contributions from energy interests). Science can inform our public policy debate, but it cannot make our decisions for us.

Fossil fuels are fundamental to our economy. Most of our vehicles, whether for human or for cargo transport, on land, on the sea, or in the air, depend on them. To a significant extent, our homes require them for heat, air conditioning, light, food storage and preparation, communication devices, entertainment. Our industries run on them, and they are indispensable to our industrialized system of agriculture. They are used as raw materials in the production of plastics, dyes, and pharmaceuticals, among other important products. In industrialized societies, life without fossil fuels is scarcely imaginable, if not impossible: the very definition of industrial civilization seems to require fossil fuels.

Whether we continue to use them as we have, even accelerating their use as we are doing, or reduce that use to a mere trickle, which we seem to have no intention of doing, at some point in the foreseeable future, they will be gone. Petroleum, according to one quite recent estimate, will be largely gone in as few as 32 years, or possibly as few as 26 (Grant, 2005), though most observers believe that it will take about 50 years. Prior to its coming depletion, we can expect that there will be bitter struggles for the last drops of crude oil, and that market manipulators will cause chaotic swings in supplies and prices. But before that time, based on our current behavior, we can anticipate that our use of petroleum will continue to increase, right up until the apocalyptic end, when fuel-less private vehicles, based on the internal combustion engine, will litter our roads like the leaves of autumn.

Solving our coming global energy problem is essential if our industrial civilization is to survive. Allowing its causes to be cavalierly dismissed, or for the problem itself to be ignored, dealt with in a off-hand fashion, or addressed only by a self-interested few, will condemn us all to a torrid and careening climate, a devastated biosphere, and global social chaos on a scale now unimaginable.

Time is running out. In just a decade or two, the very serious consequences of our current energy policy (and other ecological transgressions, such as overfishing) will overtake us, and be obvious to all. These consequences will begin to impinge on our standard of living, and our ordinary way of life. Whether we deal successfully with this challenge will determine the kind of world our children, and theirs, will inherit. But based on our current economic, social, and political inertia, there is no reason to be optimistic.

The Election
Leonard Nathan

How did the stones vote
this time?

They voted for hardness
and few words

as the trees voted
for slow growth
upwards and a shedding
of dead dependents.

And the men?

They voted against
themselves again
and for fire
which they thought they
could control,
fire
which voted for blackened stumps
and no more elections.

(Nathan, 1980)

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