Tampa Prep 2009-2010 Impact Defense File
Ext #1: No Extinctions Now EXTINCTION RATE IS AND WILL REMAIN LOW
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- WE HAVE PASSED THE PERIOD OF MASS EXTINCTIONS—NO MORE EXTINCTIONS COMING
- ACTUAL EXTINCTION RATE IS LOW -- .08% PER YEAR
- EXTINCTION RATE LESS THAN 1% PER YEAR
- SPECIES EXTINCTION FIGURES EXAGGERATED
- Ext 2 – Emperically Denied
- Ext 3 – Captive Breeding
Ext #1: No Extinctions NowEXTINCTION RATE IS AND WILL REMAIN LOWBjorn Lomborg, Professor Political Science, University of Aarhus (Denmark), 2004, The skeptical environmentalist: measuring the real state of the world, p. 255 In fact, the latest model calculations seem to back the observations. Biologists Mawdsley and Stork have shown, on the basis of information from Great Britain, that there is a fairly constant relationship between the rates of extinction of different species. If this model is used it is actually possible to estimate the number of extinct birds from the number of extinct insects and, amazingly, these figures fit very well. Using this model it is possible to show that since 1600, 0.14 percent of all insects have died out, or 0.0047 percent per decade. But as we saw above, the extinction rate is on its way up. For this reason – and for safety’s sake – Mawdsley and Stork use an extremely high estimate by Professor Smith which says that the extinction rate will increase 12- to 55-fold over the next 300 years. This still means that the extinction rate for all animals will remain below 0.208 percent per decade and probably be about 0.7 percent per 50 years. WE HAVE PASSED THE PERIOD OF MASS EXTINCTIONS—NO MORE EXTINCTIONS COMINGAlison Motluk, Freelance Writer, 2002, Salon.com, book review, “Future Evolution” by Peter Ward, January 29, http://www.salon.com/books/review/2002/01/29/ward/ But Ward's Big Idea is a fascinating one. (Good thing, too, as this isn't the first book he's written on the topic.) Unlike the doomsayers out there, he doesn't think there's another mass extinction looming. Rather, he's convinced it's well underway, and that the worst is already over. Most of the big mammals that are going to die off already have. Among those no longer with us are the mastodons, the mammoths, the saber-toothed tiger, the giant short-faced bear. "It is visible in the rear-view mirror, a roadkill already turned into geologic litter -- bones not yet even petrified -- the end of the Age of Megamammals," he writes. ACTUAL EXTINCTION RATE IS LOW -- .08% PER YEARBjorn Lomborg, Professor Political Science, University of Aarhus (Denmark), 2004, The skeptical environmentalist: measuring the real state of the world, p. 254-5 The result can be read in the book by Whitmore and Sayer published in 1992 – and its conclusions do not exactly make boring reading. Heywood and Stuart point out that the recorded extinction figures for mammals and birds (see Table 6) are “very small.” If the extinction rates are similar for other species and if we assume 30 million species, we get an annual extinction rate of 2,300 or 0.8 percent a decade. Since the area of the rainforest has been reduced by approximately 20 percent since the 1830s, “it must be assumed that during this contraction, very large numbers of species have been lost in some areas. Yet surprisingly there is no clear-cut evidence for this.” EXTINCTION RATE LESS THAN 1% PER YEARPOLICY REVIEW, December 2001, p. http://www.policyreview.org/DEC01/jewett.html (WFU67)The loss of thousands of species per year? About 1,600,000 species have been identified. Estimates of the actual number of species range from 2,000,000 to 80,000,000. No one knows the rate of extinction or the rate at which new species are arising. The best current estimate based on actual observations, and using an extremely high estimate of the likely increase in the extinction rate, is that about seven-tenths of 1 percent of species may go extinct over the next 50 years. SPECIES EXTINCTION FIGURES EXAGGERATEDBjorn Lomborg, Professor Political Science, University of Aarhus (Denmark), 2004, The skeptical environmentalist: measuring the real state of the world, p. 249 Although these assertions of massive extinction of species have been repeated everywhere you look, they simply do not equate with the available evidence. The story is important, because it shows how figures regarding the extinction of 25-100 percent of all the species on Earth within our lifetime provide the political punch to put conservation of endangered species high on the agenda. Punch which the more realistic figure of 0.7 percent over the next 50 years would not achieve to the same degree. Ext #2 – Emperically DeniedHUMAN-INDUCED EXTINCTIONS NOTHING NEWEnvironment 1997, No. 7, Volume 39, September, p. 16Humans have been causing the extinction of plants and animals for thousands of years. Large mammals such as horses and mammoths disappeared from the Americas and Australia between 15,000 and 35,000 years ago when humans first moved onto these continents. Similarly, human colonization of the islands in the Pacific and Indian Oceans some 1,000 to 2,000 years ago (and the resulting introduction of domestic animals such as rats, dogs, and pigs) may have led to the extinction of as many as one-fourth of the world’s bird species. ECOSYSTEMS RECOVER FROM HUMAN DAMAGE Douglas Boucher, Center for Environmental and Estuarine Studies, Fall 1996, SCIENCE AND SOCIETY, p. 283 (BLUEOC 0120) Humans have been able to drive thousands of species to extinction, severely impoverish the soil, alter weather patterns, dramatically lower the biodiversity of natural communities, and incidentally cause great suffering for their posterity. They have not generally been able to prevent nature from growing back. As ecosystems are transformed, species are eliminated - but opportunities are created for new ones. The natural world is changed, but never totally destroyed. Ext #3 – Captive BreedingCAPTIVE BREEDING PROGRAMS HAVE PREVENTED EXTINCTIONKirsten Weir, editor, Current Science, 2005, “Born to be wild: can zoos save endangered animals from extinction?” January, 7, http://www.findarticles.com/p/articles/mi_m0BFU/is_9_90/ai_n9505524 Despite those obstacles, several captive-born species have been successfully reintroduced to their native habitats--including some that had gone extinct in the wild. (See "Success Stories.") Such happy endings suggest that captive breeding can play a valuable role in conservation plans. Directory: files -> documents documents -> North Mankato Taylor Library documents -> In the Red and Brown Water documents -> - documents -> I. Disaster Summary Sheet II. 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