Universe a grand tour of modern science Phần 3 docx

At that time, in Cambridge, Nicholas Shackleton was measuring, as Emiliani had done, the propor tion of heavy oxygen in forams from seabed cores. But he picked out just the small animals that originally lived at the bottom of the ocean. When there’s a lot of ice in the world, locked up ashore, the heavy oxygen in ocean water increases. With his bottom-dwelling fossils, Shackleton thought he was measuring the changing volumes of ice, during the ice ages and warmer interludes. In the seabed core used by Shackleton, Neil Opdyke of Columbia detected a reversal in the Earth’s magnetic field about 700,000 years ago. That result, in 1973, gave the first reliable dating for the ice-age cycles and the various climatic stages seen in the cores. It was by then becoming obvious to the experts concerned that the results of their researches were likely to mesh beautifully with the Milankovitch Effect. I When the snow lies all summer Milutin Milankovitch was a Serbian civil engineer whose hobby was the climate. In the 1920s he had refined a theory of the ice ages, from prior ideas. Antarctica is always covered with ice sheets, so the critical thing is the coming and going of ice on the more spacious landmasses of the northern hemisphere. And that depends on the warmth of summer sunshine in the north. Is it strong enough to melt the snows of winter? The Earth slowly wobbles in its orbit over thousands of years. Its axis swivels, affecting the timing of the seasons. The planet rolls like a ship, affecting the height of the Sun in the sky. And over a slower cycle, the shape of the orbit changes, putting the Earth nearer or farther from the Sun at different seasons. Astronomers can calculate these changes, and the combinations of the different rhythms, for the past few million years. Sometimes the Sun is relatively high and close in the northern summer, and it can blast the snow and ice away. But if the Sun is lower in the sky and farther away, the winter snow fails to melt. It lies all summer and piles up from year to year, building the ice sheets. In 1974 a television scriptwriter was in a bind. He was preparing a multinational show about weather and climate, and he didn’t want to have to say there were lots of competing theories about ice ages, when the Milankovitch Effect was on the point of being formally validated. So he did the job himself. From the latest astronomical data on the Earth’s wobbles, he totted up the changing volume of ice in the world on simple assumptions, and matched it to the Shackleton curve as dated by Opdyke. His paper was published in the journal Nature, just five days before the TV show was transmitted. ‘The arithmetical curve captures all the major variations,’ the scriptwriter noted, ‘and the core stages can be identified with little ambiguity.’ The matches were climate change 142 very much better than they deserved to be unless Milankovitch was right. Some small discrepancies in dates were blamed on changes in the rate of sedimentation on the seabed, and this became the accepted explanation. Experts nowadays infer the ages of sediments from the climatic wiggles computed from astronomy. The issue was too important to leave to a writer with a pocket calculator. Two years later Jim Hayes of Columbia and John Imbrie of Brown, together with Shackleton of Cambridge came up with a much more elaborate confirmation of Milankovitch, using further ocean-core data and a proper computer. They called their paper, ‘Variations in the Earth’s orbit: pacemaker of the ice ages’. During the past 5000 years the sunshine that melts the snow on the northern lands has become prog ressively weaker. When the Milankovitch Effect became generally accepted as a major factor in climate change over many millennia, it seemed clear that, on that time-scale, the next ice age is imminent. ‘The warm periods are much shorter than we believed originally,’ Kukla said in 1974. ‘They are something around 10,000 years long, and I’m sorry to say that the one we are living in now has just passed its 10,000 years’ birthday. That of course means the ice age is due any time.’ Puzzles remained, especially about the sudden melting of ice at the end of each ice age, at intervals of about 100,000 years. The timing is linked to a relatively weak effect of alterations in the shape of the Earth’s orbit, and there were suggestions that some other factor, such as the behaviour of ice sheets or the change in the amount of carbon dioxide in the air, is needed as an amplifier. Fresh details on recent episodes came from ice retrieved by deep drilling into the ice sheets of Greenland and Scandinavia. By 2000, Shackleton had modified his opinion that the bottom-dwelling forams were simply gauging the total amount of ice. ‘A substantial portion of the marine 100,000-year cycle that has been the object of so much attention over the past quarter of a century is, in reality, a deep-water temperature signal and not an ice volume signal.’ The explanation of ice ages was therefore under scrutiny again as the 21st century began. ‘I have quit looking for one cause of the glacial–interglacial cycle,’ said Andre ´ Berger of the Universite ´ Catholique de Louvain. ‘When you look into the climate system response, you see a lot of back-and-forth interactions; you can get lost.’ Even the belief that the next ice age is bearing down on us has been called into question. The sunshine variations of the Milankovitch Effect are less marked than during the past three ice age cycles, because the Earth’s orbit is more nearly circular at present. According to Berger the present warm period is like a long one that lasted from 405,000 to 340,000 years ago. If so, it may have 50,000 climate change 143 years to run. Which only goes to show that climate forecasts can change far more rapidly than the climate they purport to predict. I From global cooling to global warming In 1939 Richard Scherhag in Berlin famously concluded, from certain periodicities in the atmosphere, that cold winters in Europe would remain rare. Only gradually would they increase in frequency after the remarkable warmth of the 1930s. In the outcome, the next three European winters were the coldest for more than 50 years. The German army was amazingly ill-prepared for its first winter in Russia in 1941–42. Scherhag is not considered to be directly to blame, and in any case there were mild episodes on the battlefront. But during bitter spells, frostbite killed or disabled 100,000 soldiers, and grease froze in the guns and tanks. The Red Army was better adapted to the cold and it stopped the Germans at the gates of Moscow. In 1961 the UN Food and Agriculture Organization convened a conference in Rome about global cooling, and its likely effects on food supplies. Hubert Lamb of the UK Met Office dominated the meeting. As a polymath geographer, and later founder of the Climate Research Unit at East Anglia, he had a strong claim to be called the father of modern climate science. And he warned that the relatively warm conditions of the 1930s and 1940s might have lulled the human species into climatic complacency, just at a time when its population was growing rapidly, and cold and drought could hurt their food supplies. That the climate is always changing was the chief and most reliable message from the historical research of Lamb and others. During the past 1000 years, the global climate veered between conditions probably milder than now, in a Medieval Warm Period, and the much colder circumstances of a Little Ice Age. Lamb wanted people to make allowance for possible effects of future variations in either direction, warmer or colder. In 1964, the London magazine New Scientist ran a hundred articles by leading experts, about The World in 1984, making 20-year forecasts in many fields of science and human affairs. The meteorologists who contributed correctly foresaw the huge impact of computers and satellites on weather forecasting. But the remarks about climate change would make curious reading later, because nobody even mentioned the possibility of global warming by a man-made greenhouse effect. Lamb’s boss at the Met Office, Graham Sutton, said the issue about climate was this: did external agents such as the Sun cause the variations, or did the atmosphere spontaneously adopt various modes of motion? The head of the US weather satellite service, Fred Singer, remarked on the gratifying agreement climate change 144 prevalent in 1964, that extraterrestrial influences trigger effects near the ground. Singer explained that he wished to understand the climate so that we could control it, to achieve a better life. In the same mood, Roger Revelle of UC San Diego predicted that hurricanes would be suppressed by cooling the oceans. He wanted to scatter aluminium oxide dust on the water to reflect sunlight. Remember that, in the 1960s, science and technology were gung-ho. We were on our way to the Moon, so what else could we not do? At that time, Americans proposed putting huge mirrors in orbit to warm the world with reflected sunshine. Australians considered painting their western coastline black, to promote convection and achieve rainfall in the interior desert. Russians hoped to divert Siberian rivers southward, so that a lack of fresh water outflow into the Arctic Ocean would reduce the sea-ice and warm the world. If human beings thought they had sufficient power over Nature to change the climate on purpose, an obvious question was whether they were doing it already, without meaning to. The climate went on cooling through the 1960s and into the early 1970s. In those days, all great windstorms and floods and droughts were blamed on global cooling. Whilst Lamb thought the cooling was probably related to natural solar variations, Reid Bryson at Wisconsin attributed the cooling to man-made dust—not the sulphates of later concern but windblown dust from farms in semi-arid areas. Lurking in the shadows was the enhanced greenhouse hypothesis. The ordinary greenhouse effect became apparent after the astronomer William Herschel in the UK discovered infrared rays in 1800. Scientists realized that molecules of water vapour, carbon dioxide and other gases in the atmosphere keep the Earth warm by absorbing infrared rays that would otherwise escape into space, in the manner of a greenhouse window. Was it not to be expected that carbon dioxide added to the air by burning fossil fuels should enhance the warming? By the early 20th century, Svante Arrhenius at Stockholm was reasoning that the slight raising of the temperature by additional carbon dioxide could be amplified by increased evapor ation of water. Two developments helped to revive the greenhouse story in the 1970s. One was confirmation of a persistent year-by-year rise in the amount of carbon dioxide in the air, by measurements made on the summit of Mauna Loa, Hawaii. The other was the introduction into climate science of elaborate computer programs, called models, similar to those being used with increasing success in daily weather forecasting. The models had to be tweaked, even to simulate the present climate, but you could r un them for simulated years or centuries and see what happened if you changed various factors. Syukuro Manabe of the Geophysical Fluid Dynamics climate change 145 Laboratory at Princeton was the leading pioneer. Making some simplifying assumptions about how the climate system worked Manabe calculated the consequences if carbon dioxide doubled. Like Arrhenius before him, he could get a remarkable warming, although he warned that a very small change in cloud cover could almost cancel the effect. Bert Bolin at Stockholm became an outspoken prophet of man-made global warming. ‘There is a lot of oil and there are vast amounts of coal left, and we seem to be burning it with an ever increasing rate,’ he declared in 1974. ‘And if we go on doing this, in about 50 years’ time the climate may be a few degrees warmer than today.’ He faced great scepticism, especially as the world still seemed to be cooling despite the rapid growth in fossil-fuel consumption. ‘On balance,’ Lamb wrote dismissively in 1977, ‘the effect of increased carbon dioxide on climate is almost certainly in the direction of warming but is probably much smaller than the estimates which have commonly been accepted.’ Then the ever-quirky climate intervened. In the late 1970s the global temperature trend reversed and a rewarming began. A decade after that, Bolin was chairman of an Intergover nmental Panel on Climate Change. In 1990 its report Climate Change blamed the moderate warming of the 20th century on man-made gases, and predicted a much greater warming of 38C in the 21st century, accompanied by rising sea-levels. This scenario prompted the world’s leaders to sign, just two years later, a climate convention promising to curb emissions of greenhouse gases. Thenceforward, someone or other blamed man-made global warming for every great windstorm, flood or drought, just as global cooling had been blamed for the same kinds of events, 20 years earlier. I Ever-more complex models The alarm about global warming also released funds for buying more supercomputers and intensifying the climate modelling. The USA, UK, Canada, Ger many, France, Japan, China and Australia were leading countries in the development of models. Bigger and better machines were always needed, to subdivide the air and ocean in finer meshes and to calculate answers spanning 100 years in a reasonable period of computing time. As the years passed, the models became more elaborate. In the 1980s, they dealt only with possible changes in the atmosphere due to increased greenhouse gases, taking account of the effect of the land surface. By the early 1990s the very important role of the ocean was represented in ‘atmosphere–ocean general circulation models’ pioneered at Princeton. Changes in sea-ice also came into the picture. climate change 146 Next to be added was sulphate, a common form of dust in the air, and by 2001 non-sulphate dust was coming in too. The carbon cycle, in which the ocean and the land’s vegetation and soil interact with the carbon dioxide in the air, was coupled into the models at that time. Further refinements under development included changes in vegetation accompanying climate change, and more subtle aspects of air chemistry. Such was the state of play with the largest and most comprehensive climate models. In addition there were many smaller and simplified models to explore various scenarios for the emission of greenhouse gases, or to try out new subroutines for dealing with particular elements in the natural climate system. But the modellers were in a predicament. The more realistic they tried to make their software, by adding extra features of the natural climate system, the greater the possible range of errors in the computations. Despite the huge effort, the most conspicuous difficulty with the models was that they could give very different answers, about the intensity and rate of global warming, and about the regional consequences. In 1996, the Intergovernmental Panel promised to narrow the uncertainties in the predictions, but the reverse happened. Fur ther studies suggested that the sensitivity of the climate to a doubling of carbon dioxide in the atmosphere could be anything from less than 18C to more than 98C. The gr and old man of climate modelling, Syukuro Manabe, commented in 1998, ‘It has become very urgent to reduce the large current uncertainty in the quantitative projection of future climate change.’ I Fresh thinking in prospect The reckoning also takes into account the natural agents of climate change, which may have warming or cooling effects. One contributor is the Sun, and there were differences of opinion about its role. After satellite measurements showed only very small variations in solar brightness, it seemed to many experts that any part played by the Sun in global warming was necessarily much less than the calculated effect of carbon dioxide and other greenhouse gases. On the other hand, solar–terrestrial physicists suggested possible mechanisms that could amplify the effects of changes in the Sun’s behaviour. The solar protagonists included experts at the Harvard-Smithsonian Center for Astrophysics, the Max-Planck-Institut fu ¨ r Aeronomie, Imperial College London, Leicester University and the Dansk Rumforskningsinstitut. They offered a variety of ways in which variations in the Sun’s behaviour could influence the Earth’s climate, via visible, infrared or ultraviolet light, via waves in the atmosphere perturbed by solar emissions, or via effects of cosmic rays. And there was no disputing that the Sun was more agitated towards the end the 20th century than it had been at the cooler star t. climate change 147 A chance for fresh thinking came in 2001. The USA withdrew from the negotiations about greenhouse gas emissions, while continuing to support the world’s largest research effort on climate change. Donald Kennedy, editor-in- chief of Science magazine, protested, ‘Mr. President, on this one the science is clear.’ Yet just a few months later a committee of the US National Academy of Sciences concluded: ‘Because of the large and still uncertain level of natural variability inherent in the climate record and the uncertainties in the time histories of the various forcing agents (and particularly aerosols), a causal linkage between the build-up of greenhouse gases in the atmosphere and the observed climate changes during the 20th century cannot be unequivocally established.’ At least in the USA there was no longer any risk that scientists with gover nmental funding might feel encouraged or obliged to try to confirm a particular political message. And by the end of 2002 even the editors of Science felt free to admit: ‘As more and more wiggles matching the waxing and waning of the Sun show up in records of past climate, researchers are grudgingly tak ing the Sun seriously as a factor in climate change.’ Until then the Intergovernmental Panel on Climate Change had been headed by individuals openly committed to the enhanced greenhouse hypothesis—first Bert Bolin at Stockholm and then Robert Watson at the World Bank. When Watson was deposed as chairman in 2002 he declared, ‘I’m willing to stay in there, working as hard as possible, making sure the findings of the very best scientists in the world are taken seriously by government, industry and by society as a whole.’ That remark illustrated both the technical complacency and the political advocacy that cost him his job. His successor, by a vote of 76 to 49 of the participating governments, was Rajendra Pachauri of the Tata Energy Research Institute in New Delhi. ‘We listen to everyone but that doesn’t mean that we accept what everyone tells us,’ Pachauri said. ‘Ultimately this has to be an objective, fair and intellectually honest exercise. But we certainly don’t prescribe any set of actions.’ The Australian secretary of the panel, Geoff Love, chimed in: ‘We will be trying to encourage the critical community as well as the community that believes that greenhouse is a major problem.’ E T he link between carbon dioxide and climate is further examined in Carbon cycle. For more about ice and climate change, see Cryosphere. Uncertainties about the workings of the ocean appear in Ocean currents. Aspects of the climatic effects of the variable Sun appear in Earthshine and Ice-rafting events. Natural drivers of brief climate change are El Nino ˜ and Volcanic explosions. climate change 148 P unsters called it an udder way of making lambs. In 1996 at the Roslin Institute, which stands amid farmland in the lee of Edinburgh’s Pentland Hills, Ian Wilmut and his colleagues used a cell from the udder of an adult ewe to fashion Dolly, the most famous sheep in the world. They put udder cells to sleep by starving them, and then took their genes and substituted them for the genes in the nuclei of eggs from other ewes. When the genes woke up in their new surroundings they thought they were in newly fertilized eggs. More precisely, the jelly of the eggs, assisted no doubt by the experimental culture techniques, reactivated many genes that had been switched off in the udder tissue. All the genes then got to work building new embryos. One of the manipulated eggs, reintroduced into a ewe, grew into a thriving lamb. It was a clone, virtually an identical twin, of the udder owner. Who needs rams? Technically speaking, the Edinburgh scientists had achieved in a mammal what John Gurdon at Oxford had done with frogs from 1962 onwards, using gut cells from tadpoles. He was the first to show that the genetic material present in specialized cells produced during the development of an embryo could revert to a general, undifferentiated state. It was a matter of resetting the embryonic clock to a stage just after fertilization. Headlines about Dolly the Sheep in February 1997 provoked a hubbub of jour nalists, politicians, and clerics of all religions, unprecedented in biology. Interest among the global public surpassed that aroused 40 years earlier by the launch of the first artificial satellite Sputnik-1. Within 24 hours of the news breaking, the Roslin scientists and their commercial partners PPL Therapeutics felt obliged to issue a statement: ‘We do not condone any use of this technology in the cloning of humans. It would be unethical.’ Also hit-or-miss. Such experiments in animals were nearly always unsuccessful. The first formal claim of a cloned human embryo came from Advanced Cell Technology in Massachusetts in 2001. At the Roslin Institute, Wilmut was not impressed. ‘It’s really only a preliminary first step because the furthest that the 149 embryo developed was to have six cells at a time when it should have had more than two hundred,’ he said. ‘And it had clearly already died.’ The 21st century nevertheless opened on a world where already women could participate in sex without ever conceiving, or could breed test-tube babies without coition. Might they some day produce cloned babies genetically identical with themselves or other designated adults? Whether bioethical committees and law-makers will be any wiser than individuals and their families, in deciding the rights and wrongs of reproduction, who knows? But cloning is commonplace throughout the biosphere. The answer to a basic scientific question may therefore provide a comment on its advisability. Why do we and most other animals rely on sex to create the next generation? I The hard way to reproduce Gurdon’s cloned frog and Wilmut’s cloned sheep rewound the clock of evolution a billion years to the time when only microbes inhabited the Earth. They had no option but to clone. Even now, the ordinary cells of your body are also clones, made by the repeated division of the fertilized egg with which you began. But your cells are more intricate than a bacterium’s, with many more genes. The machinery for duplicating them and making sure that each daughter cell gets a full set of genes is quite complicated. Single-celled creatures like yeasts were the first to use this modern apparatus, and some of them went on to invent sex. The machinery is an add-on to the already complicated management of cells and genes. It has to make germ cells, the precursors of eggs and sperm cells. These possess only half of the genes, and the creation of a new individual depends on egg and sperm coming together to restore the complete set of genes. If the reunion is not to result in a muddle, the allocation of genes to every germ cell must be extremely precise. Sex can work at the genetic level only if the genes are like two full packs of cards. They have to be carefully separated when it’s time to make germ cells, so that each gets a full pack, and doesn’t finish up with seven jacks and no nines. That’s why our own genes are duplicated, with one set from ma and the other from pa. The apparatus copies the two existing packs from a potential parent’s cells, to make four in all, and then assigns a pack to each of four germ cells. Life was exclusively female up to this moment in evolutionary history. Had it stayed all girly, even the partitioning of the genes into germ cells would not rule out self-fertilization. Reversion to cloning would be too easy. To ensure sex with another individual, fertilization had to become quite hard to accomplish. For awkwardness’ sake, invent males. Then you can generate two kinds of germ cells, eggs and sperm, and with distinctive genes you can earmark the males to cloning 150 produce only the sperm. Certain pieces of cellular machiner y, with their own genes, have to go into female or male germ cells, but not both. Compared with all this backroom molecular engineering in ancient microbes, g rowing reptiles into dinosaurs or mammals into whales would be child’s play. The germ cells have to mature as viable eggs and spermatozoa. These have to be scattered and brought together. When animals enter the picture you are into structures like fallopian tubes and penises, molecular prompters like testosterone, and behavioural facilitators such as peacocks’ tails and singles bars. Sex is crazy. It’s as if a manufacturer of bicycles makes the front parts in one town and the rear parts in another. He sends the two night shifts off in all directions, riding the pieces as unicycles, in the hope that a few will meet by moonlight at the roadside and maybe complete a bike or two. Aldous Huxley did not exaggerate conceptually (though, with a poet ’s licence, a little numerically) when he wrote: A million million spermatozoa All of them alive: Out of their cataclysm but one poor Noah Dare hope to survive. Even in plants and animals fully equipped with the machinery for sex, the option of reverting to virgin births by self-fertilization remains open. Cloning is commonplace in plants and insects. Tulip bulbs are not seeds but bundles of tissue from a parent that will make other tulips genetically identical with itself. The aphids infesting your roses are exact genetic copies of their mother. Most cloners have recourse to sex now and again, but American whiptail lizards, Cnemidophorus uniparens, consist of a single clone of genetically identical females. I Why go to all the trouble? Life without males is much simpler, so shouldn’t they have been abolished long ago? Evolution is largely about the survival of genes, but in making an egg cell the mother discards half of her genes. The mating game is costly in energy and time, not to mention the peril from predators and parasites during the process, or the aggro and angst in the competition for mates. ‘I have spent much of the past 20 years thinking about this problem,’ John Maynard Smith at Sussex confessed in 1988, concerning the puzzle that sex presents to theorists of evolution. ‘I am not sure that I know the answer.’ For a shot at an explanation, Maynard Smith imagined a lineage of cloned herrings. In the short run, he reasoned, they would outbreed other herrings, and perhaps even drive them to extinction. In the long run, the cloned herrings cloning 151 [...]... that way, as additions to a Siberian core starting around 30 0 million years ago The regions include the Ural Mountains of Russia and a swath of Central Asia reaching to Mongolia and beyond Again following Suess, Sengor called them the Altaids, after the magnificent Altai mountain range that runs from Kazakhstan to China ‘The Tethysides and the Altaids cover nearly a half of the entire continent of. .. the concave eastern seaboard of North America and the bulge of Morocco, and the way convex Brazil fits neatly into the corner of West Africa, had struck many people since the first decent maps of the world became available in the 16th century So you fit those back together, abolishing the Atlantic Ocean, and the job is half-done East of Africa it’s trickier, because Antarctica, India and Australia could... farther back in time The Earth is 4550 million years old, and scraps of continental material survive from 38 00 million years ago, when an intense bombardment by comets and asteroids ended Before Pangaea of 200 million years ago, and Pannotia of 800 million years ago, there are rumours of previous supercontinents 1100, 1500 and 230 0 million years ago Rodinia, Amazonia and Kenora are names on offer, but... southern flank from Spain to Bulgaria This summary conceals many details of the history, like the Hercynian forests of Germany that laid down great coal reserves, the rifting of the North Sea where oil gathered, and an extraordinary phase when the Mediterranean Sea dried out as a result of the blockage of its link to the Atlantic, leaving thick deposits of salt Rotation of blocks is another theme Spain,... line of the Ural Mountains The impacts of the new pieces made hook-shaped mountain ranges, which run east from Lake Baikal to the sea, and then north through the Verkhoyansk range The graveyard of slabs consumed in these collisions record part of the slow work of assembling the next supercontinent around Eurasia, which is essentially stationary just now Africa is alongside already Perhaps Australia and... Gondwana-Land in various ways Alan Smith at Cambridge combined data about matching rock types, magnetism, fossils and climatic evidence, and juggled pieces by computer to minimize gaps, in order to produce the first modern map of Pangaea by 1970 Ten years later he had a series of maps, and movies too, showing not only how Pangaea broke up but also how it was assembled, from free-ranging North America,... population, clones are more vulnerable to disease agents and parasites A sexual species seethes with what Hamilton called dynamic polymorphism, meaning an endlessly shifting choice of variant forms of the same gene Faced with an unlimited range of dangers old and new, from infectious agents and parasites, no individual can carry genes to provide molecular resistance against all of them A species is more... International Space Station Calculations suggested that a realistic instrument in space could detect several events every day The sources in the Universe of the ultra-high-energy cosmic rays may also produce gamma rays, which are like very energetic X-rays Hitting the Earth’s air, the gamma rays cause faint flashes of light An array of four telescopes, called Hess after the discoverer of cosmic rays, was created... would carry two 176 c ryo s p h e r e radar altimeters a metre apart, astride the track of the spacecraft By combining radar altimetry with aperture synthesis, scientists could expect more accurate height measurements, averaged over narrower swaths ‘If the great ice sheets of Antarctica and Greenland are changing, it’s most likely at their edges,’ explained the space glaciologist Duncan Wingham of University... London, leader of the CryoSat project ‘But the ice sheets end in slopes, which existing radar altimeters see only as coarse averages of altitudes across 15 kilometres of ice With CryoSat’s twin altimeters we’ll narrow that down to 250 metres.’ Radarsat-1, a Canadian satellite launched in 1995, gave a foretaste of surprises to come Scientists in California used the synthetic-aperture radar on Radarsat-1 . Met Office dominated the meeting. As a polymath geographer, and later founder of the Climate Research Unit at East Anglia, he had a strong claim to be called the father of modern climate science. . ocean appear in Ocean currents. Aspects of the climatic effects of the variable Sun appear in Earthshine and Ice-rafting events. Natural drivers of brief climate change are El Nino ˜ and Volcanic. malaria parasite in 2000, at the age of 63. He had gone to Africa to collect chimpanzee faeces. Playing the forensic biologist, he was investigating a reporter’s claim that AIDS arose in trials