Science news

Climate Change

Both Scientific American and American Scientist have endorsed the report of the Intergovernmental Panel on Climate Change. Writing in the August 2007 issue of Scientific American five authors with expertise in climatology explain “The Physical Science behind Climate Change” in an article presenting what the journal describes as “the undeniable case for global warming.”  The editors summarise the key points as follows:

• Scientists are confident that humans have interfered with the climate and that further human-induced climate change is on the way.
• The principal driver of recent climate change is greenhouse gas emissions from human activities, primarily the burning of fossil fuels.
• The report of the Intergovernmental Panel on Climate Change places the probability that global warming has been caused by human activities at greater than 90 percent.
• Although further changes in the world’s climate are now inevitable, the future, particularly in the longer term, remains largely in our hands—the magnitude of expected change depends on what humans choose to do about greenhouse gas emissions.

American Scientist for May-June 2007 prints an executive summary of the Scientific Expert Group Report on Climate Change and Sustainable Development prepared for the UN Department of Economic and Social Affairs.

The panel of experts was convened by Sigma Xi, and the title of their report is “Confronting Climate Change: Avoiding the Unmanageable and Managing the Unavoidable.” Its conclusions regarding the policies needed to achieve those ends parallel those in Scientific American.

National Geographic for October 2007 leads with an essay by Bill McKibben on “Carbon’s New Math”, follows with an article on the future of ethanol and biofuels, and throws in a poster showing the extent of global climate change.

But what if they’re wrong?

What if the greenhouse effect is indeed a fact, but the earth is warming anyhow and the contribution of CO2 to this natural process is either negligible or non-existent? Such is the thesis of an important and challenging paper—“Environmental Effects of Increased Atmospheric Carbon Dioxide” by Arthur B. Robinson, Noah E. Robinson, and Willie Soon.

You can read it in full at http://www.oism.org/pproject/s33p36.htm

The authors argue that “the average temperature of the earth has varied within a range of about 3C degrees for the past 3000 years”; that “glaciers regularly lengthen and shorten in delayed correlation with cooling and warming trends”; that “atmospheric temperature is regulated by the sun” and that “while major greenhouse gas H2O substantially warms the Earth, minor greenhouse gases such as CO2 have little effect”; that “sea level has trended upward for the past 150 years at a rate of 7 inches per century”; and that

Predictions of catastrophic global warming are based on computer climate modelling, a branch of science still in its infancy. The empirical evidence—actual measurements of Earth’s temperature and climate—shows no man-made warming tend. Indeed, during four of the seven decades since 1940 when average CO2 levels steadily increased, US average temperatures were actually decreasing. While CO2 levels have increased substantially and are expected to continue doing so and humans have been responsible for part of this increase, the effect on the environment has been benign.

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The general position we endorse at this site is that consensus among scientists is arrived at little by little, and by the continual mutual adjustment of theory and evidence. Contradiction and conflict are normal. (See for example Science and Consensus.) While the views of a majority of climatologists are not to be idly dismissed, there are too many examples of scientific heresies that have been later found to be true for anyone to imagine that the current global warming orthodoxies are also certitudes—certainly not when huge economic costs are involved. The story of Alfred Wegener and continental drift should be a lesson to us all.

It seems to me that Robinson et al adopt a needlessly provocative anti-environmentalist tone and manner. They are surprisingly cavalier about the problem of “peak oil” and the likely consequences of this event for populations throughout the developing world. But there is no evidence that in the long run either tone or manner count for much in the sifting of evidence and the conclusions scientists draw. As for their own conclusions, here they are in full:

There are no experimental data to support the hypothesis that increases in human hydrocarbon use or in atmospheric carbon dioxide and other greenhouse gases are causing or can be expted to cause unfavourable changes in global temperatures, weather, or landscape. There is no reason to limit human production of CO2, CH4, and other minor greenhouse gases as has been proposed.

We also need not worry about environmental calamities even if the current natural warming trend continues. The Earth has been much warmer during the past 3,000 years without catastrophic effects. Warmer weather extends growing seasons and generally improves the habitability of colder regions.
As coal, oil, and natural gas are used to feed and lift from poverty vast numbers of people across the globe, more CO2 will be released into the atmosphere. This will help to maintain and improve the health, longevity, prosperity, and productivity of all people.

The United States and other countries need to produce more energy, not less. The most practical, economical, and environmentally sound methods available are hydrocarbon and nuclear technologies.

Human use of coal, oil, and natural gas has not harmfully warmed the Earth, and the extrapolation of current trends shows that it will not do so in the foreseeable future. The CO2 produced does, however, accelerate the growth rates of plants and also permits plants to grow in drier regions. Animal life, which depends upon plants, also flourishes, and the diversity of plant and animal life is increased.

Human activities are producing part of the rise in CO2 in the atmosphere. Mankind is moving the carbon in coal, oil, and natural gas from below ground to the atmosphere, where it is available for conversion into living things. We are living in an increasingly lush environment of plants and animals as a result of this CO2 increase. Our children will therefore enjoy an Earth with far more plant and animal life than that with which we now are blessed.

Reading

A good book providing a long-term perspective on climate change is Ice Age, by John and Mary Gribbin. In one hundred brisk and enlightening pages this tells the remarkable story of how the concept of “ice ages” (or widely varying post-Pliocene climatic conditions) grew from mere theory to accepted fact.

Uniformitarianism versus catastrophism, Charles Lyell versus the early Louis Agassiz, the observations of Swiss glacial moraines by the mountaineer Jean-Pierre Perraudin and the geologist Jean de Charpentier… All this leading on to such astronomical matters as the precession of the equinoxes, the role of Earth’s tilt, wobble, and orbital eccentricity, the calculations of Leverrier—and most of all the dogged thirty-year-long pencil calculations of Milutin Milankovitch.

We should mention too a book by a man Gribbin and Gribbin describe as “the doyen of late 20th-century climatology—Climate: Present, Past and Future by Hubert Lamb.

Microbiology

Get with the archaea. Even three billion years ago these pioneering microbes were communally sharing their genes. This exemplary process is called horizontal gene transfer, and if we can believe Freeman Dyson (who writes about it in The New York Review for July 19 2007) it is both politically correct and biologically progressive. Dyson argues along these rather surprising lines when discussing an article by Nigel Goldenfeld and Carl Woese, “Biology’s Next Revolution”, that appeared in the January 25 2007 issue of Nature.

Horizontal gene transfer is what our genetically engineered biotechnological future will see lots of. What will it look like? According to Dyson trees will have sooty-dark leaves made of silicon, and there’ll be new Black Forests everywhere.

Carl Woese’s phylogenetic taxonomy rearranged the microbial tree of life (proposing the three branches of bacteria, archaea, and eukaryota, instead of the simple bipartite division of prokaryota and eukaryota). As for Freeman Dyson, it seems to this reader that he too easily gets carried away. Not only does he foresee black trees, he is confident that biotechnology should be able to both “engineer termites to chew up derelict automobiles” and deal with poverty in Africa. If only.

Liquid-Mirror Telescopes

Conventional astronomical telescopes use glass mirrors that cost heaps. In American Scientist for May-June 2007 Paul Hickson writes about a cheaper alternative. Rotating a horizontal dish covered with mercury produces exactly the paraboloid surface required to focus light. Now the University of British Columbia is building the Large Zenith Telescope, an instrument with a 6-meter-diameter mercury mirror rotating at 7 revolutions per minute.

The idea’s been around for some time. Hickson says it was first demonstrated back in 1872 by Henry Skey of the Dunedin Observatory in New Zealand using a 35cm mirror. In 1909 the American physicist Robert W. Wood of Johns Hopkins built a successful 51cm diameter mirror that was able to resolve the Lyrae system. But the image was hard to stabilise. Only today, with air bearings for support and CCDs for imaging, are liquid-mirror astronomical telescopes coming into their own.

The system has one big limitation. Because the rotational axis of the mirror is vertical, the telescope is only able to look straight up and observe the sky directly overhead—at the zenith. Nor can it track. But “drift-scanning” with CCDs helps get around that obstacle. New drift-scanning techniques enabled a liquid-mirror team in Belgium to follow objects in the sky for up to 30 minutes. Promoters dream of putting a 100-meter mirror on the moon—an idea that already has NASA’s support. The article in American Scientist is liberally illustrated.

Ethics & Evolution

The Economist for October 6 2007 describes psychological research on fairness and patience and how these attributes evolved. One study found that chimps were four times as patient as you and me. Mmmm. Maybe. Maybe they’re four times as confused. A finding about fairness comes from the Max Planck Institute for Evolutionary Anthropology in Leipzig where researchers asked chimps to play the ultimatum game. The result, reported in Science, suggests “that chimps are simply rational maximisers—Pan economicus, if you like.”

In other words, in contrast to humans big alpha chimps grab all the raisins and to hell with fairness. But is fairness cultural or genetic in humans? Twin-tests by Bjorn Wallace of the Stockholm School of Economics (writing in the Proceedings of the National Academy of Sciences) show that the sense of fairness appears to be genetic. Identical twins agreed on what were fair shares; fraternal twins did not.

In American Scientist for May-June 2007 three books about the evolution of morality are reviewed by David Sloan Wilson—The Altruism Equation: Seven Scientists Search for the Origins of Goodness, by Lee Alan Dugatkin, Primates and Philosophers: How Morality Evolved, by Frans de Waal, and The Evolution of Morality by Richard Joyce. Once again a lot of the argument turns on the questions “do chimps have different ethical principles? Is their ‘altruism’ the same as ours?” De Waal has spent much of his academic life affirming the continuity of chimp-to-human moral understanding; others stress the disjunction.

Reviewer David Sloan Wilson says that Richard Joyce’s main point in The Evolution of Morality is “that altruism fails to capture the essence of human morality, no matter how it evolved.” Joyce speculates that one human group may exhibit apparently moral behavior as a result of deeply evolved inhibitions, without there being a freely willed moral judgment in sight. The people belonging to such a culture don’t do bad things because they can’t do bad things. But an inhibition is not the same thing as a prohibition—or understanding why the prohibition is required.

This contrast between two overtly similar forms of behavior—one largely automatic and unmeditated and ruled by inhibition, another freely willed, optional, and governed by what Philip Rieff calls interdicts (cultural prohibitions consciously chosen, adopted, and understood)—is not unlike the contrast to be found in Henri Bergson’s The Two Sources of Morality and Religion. The contrast between the inherited and the acquired remains a central issue.

Perennial Crops

Annual crops of cereals, legumes, and oilseeds occupy about 80% of global agricultural land. They require vast areas of land and huge quantities of water, energy, and chemicals. But so what? Well, because the crops are grown annually, these inputs must be provided year after year after year, this in turn causing soil erosion, soil depletion, and water contamination.

Perennial crops might greatly reduce these environmental costs. According to an article in Scientific American for August 2007 (‘Future Farming: a Return to Roots?’ by Jerry D. Glover, Cindy M. Cox, and John P. Reganold) perennials like intermediate wheatgrass have roots up to two meters long and are highly resilient. A century-long study shows that they are “roughly 54 times more effective in maintaining topsoil than annual crops.” Wildlife also benefits. Herbicide costs for perennials are on average only 12% of costs for annuals. And perennials, the authors say, “are far more capable of sustainable cultivation on marginal lands, which already have poor soil quality or which would be quickly depleted by a few years of intensive annual cropping.”

Thousands of years of selective plant breeding went into the production of mankind’s present annual food crops. Developing a range of practical and productive perennial crops won’t be easy, and will involve much the same procedure as before: “direct domestication of wild plants and hybridisation of existing annual crop plants with their wild relatives.”

Because perennialism involves a whole complicated set of desirable properties it goes well beyond a single genetic trait, let alone a single gene. For this reason the authors say that transgenic modification (the kind of thing enthusiastically embraced by Freeman Dyson in the note above on microbiology) is unlikely to be useful in the first stages of developing perennial grains. The Scientific American article concludes with a short list of relevant papers on the relation of perennials to sustainable agriculture.

Brownian Motion

Many people have heard of Brownian motion. First reported by the botanist Robert Brown in 1828, it described the perpetual random motions of grains of pollen suspended in water. Few ordinary readers however would know the surprising fact that this phenomenon underlay Einstein’s research in 1905.

In the Notes and Records of The Royal Society for 22 September 2005 John Rowlinson discusses this fact in “Einstein: the Classical Physicist.” Just as surprising perhaps is that even as late as 1900 the very existence of atoms and molecules was still unproved. “By the end of the nineteenth century”, writes Rowlinson, “most physicists and chemists were convinced of the reality of atoms and molecules but there was a resistant core of sceptics, of whom Ostwald, Mach and Duhem are the best known, who maintained that the evidence showed little more than that atoms were convenient fictions that made some chemical calculations easier to do.”

Certainly no one had ever seen atoms, and direct evidence for their existence was lacking. Einstein always chose subjects that went to the heart of the contemporary problems of physics; he saw this gap as one that he might fill.

So what’s the connection between dancing bits of pollen, molecular matter, and Einstein’s work? Rowlinson writes that after all other possible explanations had been exhausted—that the pollen was affected by convection currents, evaporation of the water, or electrical charges—“the idea arose that the motion was caused by the bombardment of the particles by the random motion of water molecules…” Obviously no single collision with a single tiny molecule could by itself be causing a piece of pollen to move. By 1905 it seems that Einstein had heard only vaguely about Brownian motion, nevertheless

he thought that in the motion of suspended particles he might find an effect of fluctuations that was open to observation, and so establish another route to proving the reality of molecules …

Einstein had submitted a thesis about the size and motion of sugar molecules in 1905, this becoming a paper published the following year. In 1906 “he was better informed about Brownian motion and was confident that his theory should be applicable to it… Now the assumption that a suspended particle might be governed by the classical laws of hydrodynamics was more justified by the larger size of the Brownian particles than the sugar molecule of his thesis.”

A 1922 collection of Einstein’s papers on Brownian motion translated into English as A. Einstein, Investigations on the theory of the Brownian movement, was republished by Dover Publications, New York, in 1956.

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We should also mention a new book that “takes as its theme the growing understanding of Brownian motion” (Middle World: The Restless Heart of Matter and Life, by Mark Haw, Macmillan, $24.95). A favourable short review on page 280 of the May-June 2007 American Scientist says “Haw writes in a fast-paced, witty, staccato style, studding his account with vignettes of the great minds who, in the span of a few decades, flung science into the modern era.”