Amazon rainforest

19/07/2010

Predictions Revisited and Climate Change: News and Comments

Will the Amazon rainforest survive?

A flurry of stories about the rainforests confirms that the proper concern about tropical deforestation has been thoroughly confused by improper attempts to invoke man-made global warming. Before turning to thunderstorms felling trees,  let’s start with the big picture of expectations, past and present, for the Amazon rainforest. For more than 30 years, large-scale assessments have been based on satellite imagery, despite the problem that much of the forest is covered with clouds at any one time. Brazil’s own Instituto Nacional de Pesquisas Espaciais, INPE, has played a leading part.

In a forecast that proved wrong even more rapidly than The Population Bomb (see the previous post) an ecologist Philip Fearnside declared in 1982 that the Amazon forest was vanishing at an accelerating rate, with more than 40% to be gone by 1988. I told the tale in my 1991 book about remote sensing, Spaceship Earth, after visiting INPE in São Paulo.

During the 1980s Brazil found itself at war on two fronts. At home, the government tried to moderate the rate of clearances in the Amazonian forest, and police a frontier region as gun-happy as the old Wild West of the USA. Internationally, they had to deal with a rising chorus of criticism about the rate at which the forest was disappearing. In 1982, on the basis of INPE’s figures, predictions by an American scientist P.M. Fearnside amounted to a forecast that 44 per cent of the Amazonian forest would be lost by 1988.

The Brazilians greeted such estimates with frank disbelief. There then followed a contest between calculation and remote sensing to try to establish the true facts. …

In 1989, the World Bank published estimates indicating that 12 per cent of Legal Amazonia was already deforested by 1988. This was based on calculations from the state of affairs in 1980. By this time the Brazilians were growing very angry. Although the figure was far less than the Fearnside estimate, the fact that it came from the World Bank secured it a place in international environmental folklore. The Brazilians appealed again to the umpires in space: the unblinking instruments of the remote-sensing satellites.

At INPE, Roberto Pereira da Cunha decided to make a ‘wall-to-wall’ assessrnent of the deforestation in Legal Amazonia. As he remarked, ‘No one wants to do the dirty work of gathering the data. It is a very trivial task for scientists.’ Trivial, but not unlaborious. Pereira’s team assembled 234 Landsat scenes and selected for close interpretation 101 images that showed evidence of deforestation. From colour composites of three wavelength bands the scientists outlined the deforested patches, and used a grid to measure their areas. Images for different years established rates of deforestation.

The most important conclusion was that there was no acceleration: deforestation was proceeding at a more or less steady rate. As for the total recent deforestation up till the end of 1988, INPE’S answer was 5 per cent of the area of Legal Amazonia. Meanwhile, Fearnside had changed his forecast. His new figures indicated 7 per cent deforestation of Legal Amazonia by 1989 – a far cry from his 44 per cent figure of just 7 years earlier, and almost in line with INPE’s figure. In 1990 Jim Tucker and Chris Justice of NASA broadly confirmed the Brazilian result by a similar large-scale use of Landsat imagery, but with a different technique, using only a single infra-red channel.

So what do the umpires in space say now, two decades later?

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Planck’s whole sky

05/07/2010

Pick of the pics

Planck’s first overview of the cosmos

Credit: ESA / LFI and HFI Consortia

Microwaves from the entire sky, surveyed by Europe’s Planck spacecraft since August 2009, are here mapped in galactic coordinates. The centre of the Milky Way Galaxy, in Sagittarius, is in the middle. The ribbon of the Milky Way (the flat disc of the Galaxy) extends horizontally across the map, with Cygnus conspicuous towards the left and Orion towards the right. Streamers above and below the disc are regions of star formation. The more subtle mottled regions top and bottom show the cosmic microwave background, from the formation of the first atoms 400,000 years after the Big Bang. The strong microwaves from the Galaxy will have to be gauged and subtracted to reveal hidden parts of that background. Crucial for making the distinction is Planck’s range of nine different microwave frequencies, 30 to 850 Ghz, and its ability to measure the temperature of the sky to one-sixth of a degree.

In Magic Universe I call it “looking for the pattern on the cosmic wallpaper”. Named after the quantum theory pioneer, Planck is the successor to NASA’s WMAP mission. In 2003 WMAP returned wonderful information about the cosmic microwave background but did not quite pin down the theory of the Big Bang that best fits the facts. Maybe Planck will do that, and there seems little point in updating Magic Universe about the cosmic wallpaper until the full Planck results are in, after four surveys of the whole sky, in 2012.

George Efstathiou of Cambridge, the Planck Survey Scientist, says “It has taken sixteen years of hard work by many scientists in Europe, the USA and Canada, to produce this new image of the early Universe. Planck is working brilliantly and we expect to learn a lot about the Big Bang and the creation of our Universe.”

Reference for Efstathiou quote: UK Space Agency press release 5 July 2010.


How long you’ll live

02/07/2010

Updating Magic Universe

No, they can’t predict how long you’ll live

Excitement today in the media about the discovery of human genetic peculiarities associated with living to an exceptional old age leaves me sniffy. At the close of the story in Magic Universe called “Immortality: should we be satisfied with 100 years?” I recall:

On the day of his assassination, at what was then the ripe old age of 55, Julius Caesar declared, according to Shakespeare:

Of all the wonders that I yet have heard, / It seems to me most strange that men should fear; / Seeing that death, a necessary end, / Will come when it will come.

The veteran soldier would be bemused by 21st-Century hypochondria. In defiance of common sense and medical economics, the generation with the best life expectancy in history is obsessed with longevity.

Although overpopulation is said to be a great global problem, health educators insist that it is one’s duty to abjure motorbikes and butter and to live as long as possible. Yes, even though longevity may bring physical or mental incompetence so severe that it will cost more to keep you zimmering than to feed an entire African orphanage. As for the fear of death, if Christopher Columbus had been as bridled by cautious officials as astronauts are, his flotilla would not have quit the mouth of Spain’s Rio Tinto.

In the absence of significant disease, ageing sets a natural limit to the human lifespan. According to [Leonard] Hayflick it is about 125 years. Very few people lived past 75 until the 20th Century. But by 2000, 75 per cent of the inhabitants of the most affluent countries were doing so. The greying of the populations took actuaries and the medical profession by surprise.

The increase in human longevity slowed down in the closing decades of the 20th Century. Life expectancy at birth in affluent countries may level out at 80-90 years by the mid-21st Century. As the ageing process makes everyone more vulnerable to disease and gross degeneration, further prolongation of life may require medications yet to be invented.

They are not necessarily a good idea. Foreseeable problems range from tyrants who refuse to die to simply losing the carefree pleasures of retirement if young earners should decline to carry the economic burden of the elderly. Hayflick asked, ‘Would the least imperfect scenario be a future society in which everyone lived to their 100th birthday in good physical and mental health, then to die on the stroke of midnight?’

As Magic Universe relates earlier, Hayflick is the US microbiologist who around 1960 falsified a 30-year-old assertion by a French Nobel prizewinner that ordinary animal cells grown in a lab culture would thrive indefinitely. The natural lifespan of cells in culture, through a few dozen divisions at most, came to be called the Hayflick limit. In 1971, Alexey Olovnikov in Moscow speculated that every time a cell divides the telomeres, the DNA tie-strings at the very ends of the chromosomes, get slightly shorter, and this conjecture was fully verified 20 years later by the Canadian-born biochemist Calvin Harley and his colleagues.

Meanwhile, Thomas Kirkwood at Newcastle pointed out that burdening an animal with the genetic resources that might delay ageing is pointless if it is going to die young, because of the hazards of life. There is a trade-off between youthful vigour and provision for later life. Kirkwood called his idea the disposable soma theory, and evidence in its favour accumulated in the decades that followed.

Any update belongs before the closing section that I’ve quoted, because that still represents Hayflick’s opinion and my own.

Today’s update

Long life runs in families, and the genetics began to emerge in 2010. After comparing DNA from more than a thousand centenarians with a similar sample from the general population, Thomas Perls and his and colleagues at Boston University reported that they had found “genetic signatures” of exceptional longevity. These took the form of clusters of misprints in the DNA called “single-nucleotide polymorphisms” or snips, and 90% of centenarians could be grouped into one or another of 19 different clusters. Besides predicting exceptional longevity with 77% accuracy, using 150 snips, the team found variations between the clusters in the onset of age-associated diseases.

About these results from Boston, Kirkwood at Newcastle commented:

They are not suggesting that they can screen the genes of you and me, for example, and tell us the chance we will live to 100. This would be a tall order indeed, given that only a quarter of what determines the length of human life is genetic. … From what we know already, it is rather unlikely that genetic screens will ever be able to forecast how long an individual will live.”

References for the Update

N. Calder, Magic Universe, pp. 423-428, Oxford UP 2003

Perls ref.: Paola Sebastiani et al., “Genetic Signatures of Exceptional Longevity in Humans”, Science Express, 1 July 2010.

Tom Kirkwood, The Independent (London), 2 July 2010

ADDITION 3 July. I really should take the opportunity to put in a brief but more significant update, about the role of telomerase. It also gives me a diagram for the blog, and it reassures me in my lifelong self-imposed task of reporting Nobel-prizewinning discoveries long before the prizes are handed out.


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Freeze and evolve

01/07/2010

Updating The Chilling Stars and Magic Universe

When cosmic rays freeze the world, you’d better evolve

2100 million year-old multicellular fossil found in Gabon. Image: Kaksonen CNRS

Transforming the story of life on the Earth is a report in Nature today about multicellular creatures more than 2 billion years old, at a time when single-celled bacteria supposedly reigned supreme. Fossils you can pick up with your fingers, found in Gabon, West Africa, are far, far older than the multicellular animals that become detectable about 600 million years ago (Ediacaran period) and conspicuous 542 million years in the “Cambrian explosion”. The age is fixed with remarkable precision at 2070 to 2130 million years.

Exterior and interior of a fossil imaged by micro-tomography. Image: El Albani & Mazurier, CNRS

A team of 21 experts from France, Sweden, Denmark, Canada, Germany and Belgium make the report. The lead author is Abderrazak El Albani, at the University of Poitiers, France. He tells Agence France Press that “More than 250 specimens have been found so far. They have different body shapes, and vary in size from one to 12 centimetres.”

What excites me about the discovery is that here was a far-reaching evolutionary response to the rise of oxygen in the Earth’s atmosphere beginning more than 2000 million years ago. It occurred in the aftermath of a planet-wide freeze for which there is a cosmic explanation.

Chapter 6 in The Chilling Stars includes the story of “Snowball Earth” events. Here are some extracts.

In 1986, George Williams and Brian Embleton in Australia used the magnetism in grains of iron oxide dropped from ancient ice to show that they were released within a few degrees of the Equator. A few years later, Joseph Kirschvink of the California Institute of Technology confirmed this result in magnetism associated with other rock formations in Australia produced by ice action, and well dated as 700 million years old. He called it ‘bullet-proof evidence’.

It now seems clear that these extensive, sea-level deposits … were formed by widespread continental glaciers which were within a few degrees of the equator. The data are difficult to interpret in any fashion other than that of a widespread, equatorial glaciation.”

Kirschvink invented the name Snowball Earth for that dire climatic state. You have to visualise ice sheets, glaciers and frozen seas even at the Equator itself. The degree of ocean freezing is still debated. Some investigators imagine vistas of ice a kilometre thick or more, others prefer a ‘slushball’picture with drifting sea ice and icebergs. Either way the impact on life was severe.

Evidence from all the world’s continents unpacks into about three separate snowball episodes in the interval 750 to 580 million years ago. Worms that survived by scavenging the sea-bed detritus evolved the body-plans that made possible the explosion of animal life mentioned in the previous chapter, when the world became reliably warmer again in the Cambrian Period that started 542 million years ago.

Those cold Neo-Proterozoic times, as geologists call them, were not the only occasion of such radical events involving ice and evolution. By the end of the 20th century, geologists had amassed evidence from South Africa, Canada and Finland that confirmed two Snowball Earth episodes between 2,400 and 2,200 million years ago, in Palaeo-Proterozoic times. Our planet was then only half its present age.

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Better Remedy for Jet Lag?

26/06/2010

Updating Magic Universe

A Better Remedy for Jet Lag?

The word from the Max-Planck-Institut für biophysikalische Chemie in Göttingen is that the biological clocks associated with different organs in the body adapt to a new time zone at different rates — but the consequent physiological confusion of jet lag can be reduced, at least in mice, by attending to the adrenal glands, on the kidneys.

Coordinated bioclocks. Image: MPIBPC

A pacemaker in the brain’s hypothalamus, a group of cells called the suprachiasmatic nuclei (SCN), is supposed to synchronize all the other circadian [about a day] clocks. But the adrenal clocks are tasked to prevent over-rapid responses to changes in daylight, for example due to storm clouds. When the researchers either switch off the adrenal clocks or manipulate the synthesis of the hormone corticosterone by the adrenal glands, with the help of the drug metyrapone, the mice adapt more quickly to a new simulated time zone.

Most relevant in Magic Universe is the following passage in the story “Biological clocks: molecular machinery that governs life’s routines”. Read the rest of this entry »


Wisdom of Kilgore Trout

25/06/2010

Predictions Revisited, Updating Magic Universe, and Climate Change: News & Comments

The Wisdom of Kilgore Trout

While checking a reference for yesterday’s posting I came across an epigram concerning human behaviour that I declared, back in 1983, should rank with Einstein’s E=mc2 in physics. I quoted it in 1984 and After, but it really ought to be written on every blackboard in the world.

Who said so? None other than Kilgore Trout, the imaginary science fiction writer invented by the real-life science fiction writer, Kurt Vonnegut. In Breakfast of Champions, Vonnegut re-caps a Trout story called Plague on Wheels.

A space traveller called Kago told the Earthlings about the self-reproducing automobiles on a dying planet named Lingo-Three.

Kago did not know that human beings could be as easily felled by a single idea as by cholera or the bubonic plague. There was no immunity to cuckoo ideas on Earth.” Within a century of Kago’s arrival the Earth was dying too, littered with the shells of automobiles.

Getting an interview with Vonnegut was never easy, but when I managed it my key question was whether Kilgore Trout’s epigram expressed his own opinion. He said, Yes it did.

Before this accidental prompt, I wasn’t going to bother to comment on a paper published this week in the Proceedings of the National Academy of Sciences, no less. Anderegg et al. claim that scientists convinced about man-made global warming are cleverer and better respected, as well as much more numerous, than scientists who are unconvinced.

Now I’ll say that it’s scary but not surprising that the National Academy of Sciences should permit a division of experts into an ingroup and an outgroup, and an evaluation of them by arbitrary tests that have nothing whatever to do with the inherent substance or merit of their research. Unsurprising because it accords with Kilgore Trout’s insight into human behaviour, which has been well verified in psychological experiments.

Alec Nisbett of BBC-TV filmed one experiment called Klee-Kandinsky, executed for real with unsuspecting schoolboys, for our documentary “The Human Conspiracy” (1975).  I also summarize the experiment in Magic Universe, in the story “Altruism and aggression: looking for the origins of those human alternatives”.

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Self-organizing colours of butterflies

17/06/2010

Updating Magic Universe

Self-organizing colours of butterflies

The papilionid Emerald-patched Cattleheart, Parides sesostris. Source: Richard Prum

A multi-disciplinary study at Yale, by evolutionary biologists, physicists and various kinds of engineers, aided by X-ray scattering specialists at the Argonne National Laboratory, has clarified the way in which butterfly wings generate shimmering colours. The wings employ a physical trick of the light that’s more influential than any chemical pigments. The team, led by biologist Richard Prum, has published the findings in this week’s on-line issue of the Proceedings of the National Academy of Sciences.

A gyroid, as visualized by Alan Schoen. Image from NASA

Complex curved assemblies of molecules called gyroids do the trick, by scattering light in distinctive ways that depend on the dimensions of the gyroids, the slant of incoming light, and the angle of view. Digging a little, I find that a mathematician, Alan Schoen, discovered gyroids as possible shapes, long before their biological role was known. In 1970, while at the Electronics Research Center in Cambridge, Massachusetts, Schoen wrote a paper for NASA that began: “A preliminary account of a study of the partitioning of three-dimensional Euclidean space into two interpenetrating labyrinths by intersection-free infinite periodic minimal surfaces …” Key words there are “labyrinths” and “periodic”.

But how does a butterfly, however mathematically astute, set about building its gyroids?  According to Prum and his chums, the outer membrane of a cell in the butterfly’s wing folds into the cell’s interior from above and below to make a double gyroid. Then starchy chitin forms on the outer gyroid to solidify it before the cell dies – leaving the colour-generating crystal form on the surface of the wing.

Here’s the most relevant story in Magic Universe. It’s called “Molecular partners: letting natural processes do the chemist’s work”.

Strasbourg or Strassburg lies in the rift valley between the Vosges and the Schwarzwald, down which the Rhin or Rhein pours. The city is closer to Munich than to Paris, and repeated exchanges of territory between the French and the Germans aggravated an identity problem of the people of Alsace. It was not resolved until, after restoration to France in 1945, Strasbourg became a favoured locale for Europe-wide institutions. But history left the Alsatians better able than most to resist the brain drain to Paris, and to pursue their own ideas, whether with dogs, pottery or science.

As a 28-year-old postdoc in Strasbourg, Jean-Marie Lehn embarked in 1967 on a new kind of chemistry that was destined to become a core theme of 21st-Century research worldwide. It would straddle biology, physics and engineering. As it concerned not individual molecules, made by bonding atoms together, but the looser associations and interactions between two or more molecules, he called the innovation supramolecular chemistry.

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Comets and life 3

04/06/2010

Updating Comets and Magic Universe

Did comets spark life on Earth?

Part 3 Initiating biochemical action

Pascale Ehrenfreund rides again (as in Part 2) in the story in Magic Universe called “Life’s origin: will the answer to the riddle come from outer space?”. But please focus first on Wlodzimierz Lugowsky.

I can trace my ancestry back to a protoplasmal primordial atomic globule,’ boasts Pooh-Bah in The Mikado. When Gilbert and Sullivan wrote their comic opera in 1885 they were au courant with science as well as snobbery. A century later, molecular biologists had traced the genetic mutations, and constructed a single family tree for all the world’s organisms that stretched back 4 billion years ago, to when life on Earth probably began. But they were scarcely wiser than Pooh-Bah about the precise nature of the primordial protoplasm.

In 1995 Wlodzimierz Lugowsky of Poland’s Institute of Philosophy and Sociology wrote about ‘the philosophical foundations of protobiology’. He listed nearly 150 scenarios then on offer for the origin of life and, with a possible single exception to be mentioned later, he judged none of them to be satisfactory. Here is one of the top conundrums for 21st Century science. The origin of life ranks with the question of what initiated the Big Bang, as an embarrassing lacuna in the attempt by scientists to explain our existence in the cosmos.

After discussing possible “home cooking” of life by hypercycles, RNA catalysis or lipid catalysis, and touching on the possibility of false starts, the tale turns back to the sky in pursuit of the only hypothesis acceptable to Lugowsky.

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What did Hawking discover?

04/06/2010

Updating Einstein’s Universe and Magic Universe

What did Stephen Hawking discover?

Stephen Hawking. Photo: Channel 4

We’re so used to it, we’re not surprised to see an elderly gentleman immobile in a wheelchair, his lips hardly moving, performing for most of this week as the host presenter of Channel 4 TV’s five-part history-of-science series “Genius of Britain”. Like the footballer David Beckham or the actress Joanna Lumley, the theoretical physicist Stephen Hawking is now a national treasure. And with his voice synthesiser he can seem like a visitor from outer space, setting us earthlings right about this and that.

But I’m irritated by the implication in the last programme, which I’ve just watched, that Hawking himself was a primary advocate of the Big Bang, in opposition to the great Fred Hoyle’s Steady State Theory. No mention of the l’atome primitif of the Belgian cosmologist Georges Lemaître in 1927, but he was a Catholic priest and perhaps inadmissible to Hawking’s co-presenter Richard Dawkins. No mention either of Martin Ryle, the Cambridge radio astronomer who first showed observational evidence that confounded Hoyle’s expectations.

Three decades ago, the BBC’s Alec Nisbett and I were the first to put Hawking on international television, in a two-hour blockbuster on particle physics, “The Key to the Universe”. At that time, his dreadful disease of nerve and muscle left his mumbles intelligible only those most familiar with him. We added a voice over, as if he were speaking a foreign language.

For Nisbett and me, Hawking was not only an up-and-coming physicist but an image of the frailty of Homo sapiens confronted by a confusing and often violent cosmos. After describing his then-recent suggestion that small black holes could explode, producing new particles, we incited Hawking to use stirring words to climax our show.

The Big Bang is like a black hole but on a much larger scale. By finding out how a black hole creates matter we may understand how the Big Bang created all the matter in the Universe. The singularity in the Big Bang seems to be a frontier beyond which we cannot go. Yet we can’t help asking what lies beyond the Big Bang. Why does the Universe exist at all?

My son Robert is always asking questions. Why this? Why that? Every child does. It is what raises us from being cavemen.

On one view, we are just weak, feeble creatures at the mercy of the forces of Nature. When we discover the laws that govern those forces we rise above them and become masters of the Universe.

Hawking then rose to stardom, taking up Newton’s chair as Lucasian Professor of Mathematics in Cambridge in 1979, and publishing the phenomenal best-seller A Brief History of Time in 1988. He has appeared frequently in “The Simpsons” as well as in scientific documentaries and docu-dramas. He made a sub-orbital spaceflight in 2007 at the age of 65 and during the weightless period he could move freely in his chair for the first time in four decades.

His courage, doggedness and success in the face of a crippling disease has been inspirational to paraplegics the world over. Concern for his predicament has also encouraged many people who might otherwise not have been interested in science to pay some attention to it.

In those respects I’m second to none in my admiration of Hawking. But we’re entitled to ask, as about any other scientist, what his enduring contribution to progress in research has been.

To try to get the tone right, I’ll begin by quoting an eminent but more reclusive theorist, Peter Higgs of Edinburgh, who saw the need for a particle that would give mass to matter, and how it might work. The race to find the Higgs particle, a.k.a the God particle, is now on, using the most powerful accelerators of our time.

But Higgs found himself in hot water during the Edinburgh Festival of 2002. He attended a dinner party celebrating a play based on the work of Paul Dirac, who predicted the existence of antimatter. It was not surprising that the conversation turned to why the public, who knew about Hawking, had never heard of the more important Dirac.

Thinking the dinner was private, Higgs commented about Hawking: “It is very difficult to engage him in discussion, and so he has got away with pronouncements that other people would not. His celebrity status gives him instant credibility that others do not have.”

Next morning Higgs found his remarks quoted in The Scotsman and repeated widely elsewhere. The shocked reaction confirmed Higgs’s point, that someone considered superlatively brilliant as well as handicapped was supposed to be exempt from the normal give and take with his fellow scientists.

Let’s check what I say about Hawking in Einstein’s Universe and Magic Universe and ask

  • Is it fair?
  • Does it need updating?

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Comets and life 2

01/06/2010

Updating Comets and Magic Universe

Did comets spark life on Earth?

Part 2: Cosmic carbon compounds

An earlier post, Part 1 under this heading, commented enthusiastically but briefly on a French team’s find of extraterrestrial dust grains rich in carbon in the snow of Antarctica. https://calderup.wordpress.com/2010/05/10/comets-and-life/

I promised more to come, and here it begins. Part 2 deals with cosmic carbon compounds. Later, Part 3 will reconsider the initiation of biochemical action, and Part 4 will look at suggestions of natural life footloose in space.

There were far more comets around when the Solar System was young, in the “heavy bombardment” phase of Earth history lasting until 3.8 billion years ago. Water is abundant in interstellar space and available to build the icy nuclei of comets. Comets may have delivered most of the Earth’s surface water, essential for life.

Carbon compounds are the other main ingredient for life. Comets’ tails consist mainly of small dust grains released from the nuclei, including grains laden with carbon compounds that may have contributed to the origin of life on the Earth. Here’s a general impression of important “prebiotic” molecules made in the vicinity of dying stars and newborn stars and available for incorporation into comets.

PAHs, polyaromatic hydrocarbons observable in interstellar space, could be ancestral to the aromatic compounds that have the very smell of life. Illustration from Pascale Ehrenfreund & Steven Charnley, 2000 – see reference. Graphic art: ©2000 R. Ruiterkamp


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