Nexus - 0701 - New Times Magazine-pages

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... GL@BAL NEWS ... NEWS WEATHER WARNING efore 1976, but nothing like the post-1976 : oy: eriod. He has examined in detail the "return piece of fossilised coral, dated at eriod" for El Nifios, both in the ancient coral 125,000 years old, looks as if it could and modern meteorological and coral records, transform our understanding of El Nifio—the and found that, in the modern record, prior to Pacific Ocean phenomenon that is the cru- 1976 the dominant return period for El Nifio cible of much of the world's climate. was around six years. That was also the case Dan Schrag, who is based at Harvard _ in the 65-year time-slice in his ancient coral. University's Department of Earth and But the post-1976 record shows a peak return Planetary Sciences, discovered the coral while eriod at 3.5 years. The implication is that holidaying in Indonesia recently. the cycling of El Nifio was highly stable over Until recently, climatologists looked on El undreds of thousands of years, but has Nifio as an aberration in the tropical Pacific, changed fundamentally in the past quarter- of only passing interest to the outside world. century. But in the past two decades, it has become the The crucial question is what lies behind this "fifth horseman of the Apocalypse", a bringer change. Has El Nifio been disturbed by some of devastating floods, fires and famine from external factor, such as global warming, or is Ethiopia to Indonesia to Ecuador and a sender __ it simply ona short-lived, exuberant joyride? of weird weather around the world. One way to check, says Schrag, is to look It has been appearing more frequently, with for signs of recent warming in the ocean. effects that last longer than ever. Its activity Together with Tom Guilderson from is unparalleled in the historical record. And — Lawrence Livermore National Laboratory in yet nobody could be sure if this is a perfectly California, he has recently pointed out that the normal blip, or an alarming consequence of unique signature of the post-1976 El Niiios is human-induced climate change. down to a very specific warming of surface For climatologists, EI Nifio is the flywheel _ waters in the eastern Pacific during the cold of the world's climate, a redistributor of heat season. This area of ocean is a constant bat- and energy that kicks in when the regular cir- _ tleground between warm waters at the surface culation systems cannot cope. In normal and cold waters that well up from the deep. times, the winds and waters flow across the Most of the time the upwelling is dominant. tropical Pacific from the Americas in the east But during El Nifios, when warm waters wash to Indonesia in the west, driven by the Earth's across the Pacific from the west, the rotation. In the tropical heat, the water warms _ upwelling is shut off. What seems to have as it goes. The result is the gradual accumula- _ happened is that this shutoff has become near tion of a pool of warm water around permanent. Indonesia that can be 40 centimetres higher Since 1976, water at the surface in the east- and several degrees warmer than water on the ern Pacific has been richer in carbon-14, other side of the ocean. This cannot last and, showing that deep water is not welling up as typically every three to seven years, this much as before. Upwelling normally keeps warm water breaks out and flows back across _ the eastern Pacific cool, maintains the normal the surface of the ocean. As the pattern of _ trade winds and so suppresses the outbreak of ocean currents shifts, so do the wind and air _ El Nifios. Reduce the upwelling and the sys- pressure systems associated with it—and with tem is permanently primed for an EI Nifio. them, the weather. So the wet rainforest cli- | Schrag concludes that the post-1976 change mate of Indonesia drenches the normally arid _ in the thermocline may be responsible for the Pacific islands and often reaches the coastal _ increase in the frequency and intensity of El deserts of the Americas. Meanwhile, Nifio events since then. Indonesia and much of Australia dry out. Does any of this matter beyond the Pacific But scientists have been uncertain about Ocean? As climatologists discover more and how far back El Nifio goes. Reliable climate more about the workings of the oceans and and ocean records cover only a century or so; atmosphere, they realise how central El Niifio delving further requires an alternative source _ is to the functioning of the entire climate of information. system. Schrag's chunk of coral pushes back the The Indian Ocean shows its own post-1976 date of the first recorded El Nifio by more _ shift. Analysis of weather statistics from the than 100,000 years, to before the last ice age. remote Chagos Archipelago, by Charles In a paper due for publication shortly in Sheppard of the University of Warwick, Geophysical Research Letters, Schrag and his _ found that around the mid-1970s average air colleague Konrad Hughen will reveal their temperatures abruptly rose by a degree, while analysis of the isotopic signature of the annual _ cloud cover shrank by 50 per cent. growth layers inside the Sulawesi coral, and Is the shift in El Nifio the long-sought use it to plot the pattern of the ancient El "smoking gun" that will convict greenhouse Nifios. According to Schrag, the pattern of El _ gases of causing climatic mayhem? Nifio events revealed in his 125,000-year-old (Source: From an article by Fred Pearce, coral looks exactly like the modern period — New Scientist, London, 9 October 1999) While many were shocked about revela- tions that human sewage had been added to French cattle feed, residents from the village of Saxthorpe, north Norfolk, England, who live close to Great Farm, know that for years British cattle have been eating silage that has been cultivated on land laden with sewage. Great Farm has three lagoons which are lined with black polythene and can each hold about a million gallons of sewage sludge. "It's like a dark porridge with a thick, grey crust covering it," said Aubrey Poberefsky, 62, who lives in Saxthorpe. "It's full of bacteria and chemicals, but they have been putting thousands of gallons of it onto the fields." (Source: Sunday Times, 3/ October 1999) The Belgian Government has also admitted that human and animal waste was being mixed into animal feed until early 1999. The country's farm minister was responding to a television report which said sludge from slaughterhouses and toi- lets had ended up in Belgium's food chain. The VTR television network also report- ed that waste from slaughterhouses, toilets and showers was mixed in with animal feed in Belgium. (Source: Sightings website, 22 September 1999, www.sightings.com) NATURAL LIGHT IMPROVES STUDENT TEST SCORES Aw of three American school dis- tricts suggests that one good way to raise test scores is to let the sunshine in. The study, done by a California energy- consulting firm, may be the best evidence yet to support the commonsense notion that natural light helps people work better. Investigators with the Heschong Mahone Group rated the districts' elementary schools on the amount and distribution of light in their classrooms. They then took a standardised test result, and after control- ling for other factors that affect test perfor- mance (e.g., family income) they found that students exposed to the most daylight also had significantly higher test scores. In Seattle, students in light-filled schools scored 9 to 13 per cent higher on maths and reading tests than those with the least light. In a related study, Heschong Mahone looked at 108 stores in an unnamed retail chain and found that those with skylights had 40 per cent higher sales on average. (Source: www.abc.net.au/news/newslink/ nat/newsnat-14oct1999-26.htm) NEXUS <9 DECEMBER 1999 — JANUARY 2000