木鱼桥

意识和自我意识

所有生物都有意识?我觉得这是理所当然的,否则称不上是生物。不过若谈到自我意识,这我是不相信的,很难想象一只蚂蚁会问“我是谁”这样的问题。据说婴儿要到18个月后,才会慢慢出现和发展这种意识。据说高等的哺乳类,比如类人猿,海豚,甚至猪,甚至狗,都有一定的自我意识。那到底什么是自我意识?或者换句话说,为什么自我意识是如此重要?

作为一个唯物主义者,或者说不可知论者,我认为一个人只有一生。但到底是什么东西让我有这种想法呢?当医学足够发达,可以用我的体细胞来克隆另一个“我”的时候,我依旧断定,那个克隆出来的“我”并不是我。我们有各自的生活,各自的成长环境,各自的想法,或者再加一个,各自的“自我意识”。这个意识不是独立于我的这具肉体之外的,我的肉体的消亡必然伴随着这个意识的消亡。也许人类的科技可以发达到提取人脑,换一幅人造的身体。模拟各种信号来刺激这颗“大脑”,以另外一种方式存活下去。

这种方式也带来了另一种危险。既然人类可以模拟刺激,让这颗“大脑”仍旧以为“我”还活着,那若我被强行取出大脑,对方给我强加各种各样不堪忍受的折磨,那可真是求生不能求死不得了。就算每天哄得我的“大脑”舒舒服服,那这还算是一个人的生活吗?如果一个婴儿刚出生或者自我意识还没形成的时候,大脑就被人放进了一个类似的“模拟器”中,那等这颗大脑长大后,这还算是一个人吗?

以此类似的是,当你被不知名的力量投到了一个只有你一个人的陌生世界,只有你一个“人”,不会饥饿,没有死亡,能感知到世界,却感知不到自己,能做的只有游荡和思考。假设在很长的一段时间里(你的大脑认为那经历了漫长的时间),你有多大的把握仍旧认为你是一个人?我觉得在那种情况下,我撑不了多久。漫无边际的孤独,毫无交流,很快会奔溃,然后自我意识消失。在意识消失之前,我不敢断定,我会不会认为我曾经在那个地球上经历过的岁月是真实存在过的,抑或只是一场幻觉,有“人”强加的刺激。

但我可以想到,若在这个世界里面,加入另外一个有自我意识的生物,这个孤寂的世界立即会变得很有活力。但这也可能只是我的一厢情愿。在一个非常有限的世界里,这种活力很快会消失殆尽,两颗头脑跟一颗没多大区别,很快就会同质化。从这种角度来说,差别越大的两颗头脑,更有可能给生活带来刺激。越是同质化的社会,越是没有活力。当更多的头脑加入的时候,这个世界的复杂性越来越高,刺激越来越多,就越难走向同质,越难走入消亡。如果头脑足够多,还伴随着死亡的话,这活脱脱就是另外一个人类世界。如果不是有大规模毁灭性武器的存在,宇宙有天体相撞的危险,以及资源枯竭的忧虑,我对人类的长期存在是有信心的。

不过随着科技的进步,人类的意识正在走向同质化,一个同质化的社会必然会越来越缺少活力,虽然还远未到危险的地步。难不成说,人类社会最大的发展来自于激烈的冲突,而冲突过后则必然带来同质化,然后带来活力的衰退?这真是一个令我自己也感到惊讶和害怕的推论。

我是无法想象人类能够造出一台“类人”的电脑,能够思考,也就是说有“算法”之外的一些东西,我们通常叫做“灵感”,“自由意志”诸如此类的东西。就算人类成功造出了一台这样的机器,并且这台机器能够不断学习,并有自我身份认同,“它”也很难跟人类完全一样。人类经过这么多年的进化,成了现在这样的模样,有着现在这样的基因,从而带来各种各样的潜意识的欲望、喜好和毛病。很多都是我们与生俱来的可以称之为本能的东西,而这些几乎是不可能以一种方式“注入”到这样的一台机器里去的。假如我们真的强大到能够做到这一步,那我们人类本身也处在一种极度危险之中。当这一天到来的时候,我们的所谓自我意识,自由意志等等都将成为人类可以控制的工具,但还有什么“自我意识”“自由意志”可言?

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2010年10月25日 Posted by | Life, 无法归类, 个人 | 留下评论

关于ΚΕΦΙ《重复澄清》以及他的态度

ΚΕΦΙ终于在牛博上更新了《重复澄清》一文,来回复小白的《澄清《澄清》》,证实了我对小白说的,ΚΕΦΙ在准备一篇长文来回复,而不是将保持沉默。

小白从来没有说过否定全球变暖,而ΚΕΦΙ一而再再而三地提到小白否认全球变暖,不知道是出于什么原因。ΚΕΦΙ的这篇文章,大约有一半在证明全球 变暖是科学家的共识(不过ΚΕΦΙ有意混淆全球变暖共识和人为全球变暖共识不知道是什么原因。另外一半则在逐字逐句地评价小白找出来的证据)。

ΚΕΦΙ再次强调了一下,“有九成以上的把握相信,人为造成的温室气体聚集,是20世纪中叶以来全球气候变暖的主导因素”。 大家看清楚了,他说的是,人为的因素,是全球气候变暖的“主导因素”。不过我去查了那篇文章的原文, 原话是这样的:”leading to very high confidence that the globally averaged net effect of human activities since 1750 has been one of warming”,翻译过来就是说,从1750年以来,我们有很大把握(也许是90%以上?)说人类活动是全球平均气温升高的一个原因。ΚΕΦΙ完全曲解 了这句话的原意,我对此为“牛逼”的ΚΕΦΙ表示悲哀。

接下来,ΚΕΦΙ在文章中有这样的话:

该调查将Science杂志涉及气候变化的928篇学术相关论文分成六类:
1.明文认可“全球变暖是共识”的、
2.评估影响的、
3.提出缓解方案的、
4.研究方法的、
5.分析古气候的、
6.反对“人为全球变暖是共识”的。
它们中,
有75%的文章属于前三类,即明说或者蕴含对“人为全球变暖共识”的承认
有25% 的文章属于第4、5两类,不涉及对“人为全球变暖”的态度,
没有文章属于第6类,即没有任何一篇反对“人为全球变暖是共识”。

我们先来看看,那篇他引用的文章里 面说了什么。“IPCC states unequivocally that the consensus of scientific opinion is that Earth’s climate is being affected by human activities”. 翻译过来就是说,IPCC 毫不含糊的陈述,科学界的共识是地球的气候是被人类活动所影响的。关于这个共识,我想没有人怀疑吧。但我们回过头来看看ΚΕΦΙ的陈述,他在第1和第6条 所提到的两个共识都不是他所引的文章所提到的共识。而且一个共识,竟然被ΚΕΦI变成了两个不同的共识,不知道是什么原因。在那个共识下面,文章中确实分 了6类,它们是:consensus position, evaluation of impacts, mitigation proposals, methods, paleoclimate analysis, and rejection of the consensus position. 这样我们就完全明白了,ΚΕΦΙ完全是在误导我们。而且就算完全按照他的思路,我也无法从前面3类里面看出,“明说或者蕴含对“人为全球变暖共识”的承 认”,只能看出对”全球变暖共识”的承认,而这点小白与我都没有否认过。这样,ΚΕΦΙ这篇文章中最有分量的资料看来是立不住脚的。

作个小结:ΚΕΦΙ在文章中提出了三个证据,结果只有最后一个证据,算是站得住脚的。不过那个证据是三个证据中最没有说服力的,因为仅仅牵涉到了一位科学家。与此相对的是,第一个证据是一篇最新的summary文章,而第二份证据牵涉了928篇文章。

下面,我对 ΚΕΦΙ谈话的态度作个总结,当然这并不影响我们讨论的结论。讨论他的态度的原因是,他的态度实在是太恶劣了。

1,ΚΕΦΙ谈到邹承鲁说的那句话:“一个真正的科学家,即便由于种种原因不能戳穿假话,或者无法说出真话,或者可以选择不说话,但至少要做到不说假话,不主动用假话去邀功请赏,去谋财害命。”,竟然说“邹老这话标准太低”,声称“出于比邹老更牛逼的境界”。我希望ΚΕΦΙ 能 先去考察一下邹老当年的科研环境和政治环境,跟你现在所处的环境做个比较,然后再想想怎么说话比较合适。ΚΕΦΙ这么说,我只能认为ΚΕΦΙ这个人既不踏 实也很嚣张,而且还是毫无理由的嚣张。我在牛博上浏览文章相当长时间了,知道ΚΕΦΙ是怎样一个人,所以我才会预测ΚΕΦΙ会写一篇很长的文章来回应,因 为 ΚΕΦΙ跟cason,戈尔一样,也是偏激的人,会选择偏激的方式。当然,我这么说并没有否认ΚΕΦΙ的结论。我再一次重申小白和我的话:因为偏激,所以至少是值得怀疑的。

2,我们都是希望把事情弄清楚,我们都在找 各种资料,希望能够得到更客观的结论,然后平实地呈现给大家看。不过在所用的方式上,我个人是非常讨厌ΚΕΦΙ的方式,用各种颜色的红笔蓝笔甚至粉红色的 笔划得到处都是,很有一种风雨欲来的压迫感。当然我可以理解国人只要结果不喜欢材料的心理,不过用在这种比较严肃的讨论中非常不适合。就像我和小白非常讨 厌戈尔的电影和《寂静的春天》一样,因为很煽情(当然,《寂静的春天》更可恶,不仅煽情,而且大量引用没有经过证实的资料)。而ΚΕΦΙ也正在做这样的事 情,生怕别人漏掉他的正确之处以及别人可能的错误之处。小白怎么看待ΚΕΦΙ的文字我不知道,但我是强压着恶心逐字逐句地看ΚΕΦΙ的文章的,太晃眼了。 其实这也是ΚΕΦΙ偏激的一个表现。

牛博网上其他人也用红色蓝色,但绝大多数只是用来区分自己的话和引用别人的话,做到你这样的,据我所知,绝无仅有。你划得再多,也不能提高你的文章质量。建议你去看看波普尔《自由主义的原则》一文,那才是好文章,因为所有句子都应该被划出来。当然,若你看不出这篇文章的价值,我爱莫能助。

3,关于第一个问题,小白说:“这0.5摄氏度的变化在媒体的宣传和夸大下已经变成了人类面临灭顶之灾的预兆,给公众的感觉好像变化的不是0.5度而是50度。”结果,ΚΕΦΙ回复,“我无语了。看来上升50度才是xiao概念中的“灭顶之灾”。” 如此曲解别人的话,我对ΚΕΦΙ表示敬佩。可能原因有两个,一个是ΚΕΦΙ语文学的不好,另外一个是ΚΕΦΙ故意曲解别人的原意。不过我倾向与第二种原因,因为他曾经在他的博客上教人家学成语,想来语文是不错的。而曲解别人的意思,他在这最新的文章里,前面已经分析过了,他做了至少3次了,而且后面在评论小白的话的时候,还出现了好几次。最明显的一次在这里:

小白说:

大气中二氧化碳含量从二战之后到现在增加了30%,但全球气温并没有大幅度变化。气温是由无数复杂因素所影响的,CO2的影响占多少成分无法确定。

ΚΕΦΙ评论:

xiao同学竟然拿二氧化碳增长幅度对比气温增值来说明二氧化碳不是全球变暖因素

4,小白的参考资料,一共47篇文章。

5,我看完了ΚΕΦΙ的这篇文章之后,有一个感觉就是,他既是研究冰川的专家,又是研究温室气体的专家,当然更是研究全球变暖的专家。我们来看看他的语录:

任何具备气候学常识的人(生态学常识都不必了)都应该明白…

我暂无篇幅和时间详述“区区几度”对海洋气候的影响,对水含氧量的影响,对冻土和冰川的影响,对疾病传播的影响等等等等

这种意见恰恰是最典型的“否认全球变暖”的意见,也是反对意见里最外行、最无知的那一类。

xiao同学和其他读者很有必要了解一下全球冰川融化的概况和趋势,

如果在80、90年代有谁这么胡扯仍可原谅;到2007年还这样说,你就是火星人了。

xiao这里拿60年代末一度流传的“气候变冷”谬论来类比现在“气候变暖”的科学知识,是一个老掉牙的、把一切“气候危机”意识归在一起“连坐”的做法,不仅本身不说明问题,也体现了对这几十年气候学发展的无知,对于没有根据的流言和有测量分析的科学都不能区分。

请问xiao同学你仔细了解过GCMs吗?你学习过气候建模是怎么回事儿吗?听起来好像你以为一个“模型” 不准就推翻了“全球变暖”,你大概不知道“全球变暖”是从简单理论到庞大的跨领域复杂理论体系,在统计学的指导下对成万上亿的、不断演进的模型们进行的大 规模计算而获得的严格结论。实际上,随着模型的演进,数据的积累,结论从总体上越来越不乐观,现实越来越比想象得紧迫。

你至少应该知道海平面持续上升是定论吧?你至少应该从平均气温变化想到全球气温分布变化吧?你至少应该想到大洋环流吧?你至少应该想到海洋生态吧?你至少应该想到流行病吧?你至少应该想到极端气候事件吧?

… …

等等诸如此类,那是琳琅满目,挂满了ΚΕΦΙ“牛逼”“专家”的文章中的角角落落,让我不禁好奇起来,这位ΚΕΦΙ“牛逼”“专家”到底是什么来头?

另外,鉴于ΚΕΦΙ讨论态度非常恶劣,我在此声明,若ΚΕΦΙ不声明道歉,我将再也不回复他的文章。

2007年03月9日 Posted by | 无法归类 | 一条评论

DDT and Silent Spring

这是下面的书中DDT一栏的全文(包括reference)。当然,这本书内还有其他很多地方也提到了DDT以及silent spring,但比较分散,而且输入也比较困难。若有兴趣的可以去找这本书看原文。若有什么输入错误的地方,请指正。

这段文字现在还只有英语,没有中文翻译。小白和我比较忙,这些天应该没有时间翻译,大家将就着先看。

Book Name: Standard handbook of Environmental Science, Health, and Technology

Editor: Jay H. Lehr & Janet K. Lehr

Location: (p21.63-21.66)

21.3.11 DDT

“The greatest killer in Africa is not AIDS or sleeping sickness, but malaria which kills an estimated 2 million children each year” (1)

Did you know?

DDT has saved more lives in the past 50 years than have antibiotics as a group. The banning of DDT is probably the largest act of genocide in human history. The Nationals Academy of Sciences estimated that DDT saved 500 million lives before it was banned (2).

Since DDT was banned, the incidence of malaria has increased enormously worldwide and the disease has again become a leading cause of death. Every 12 seconds, a child dies of malaria (3).

There is evidence suggesting that DDT is an anticarcinogen (4).

DDT’s “cousin” DDD is an anticancer drug used against inoperable adrenal-gland cancer (4, 5).

My guess is that most of you hadn’t heard the above facts. Rather, what you’ve heard, or read, is that DDT is toxic, has caused eggshell thinning in birds, accumulates in fat tissues in our bodies, and is still found in the environment. The facts are that DDT was given a bad rap in 1972 when it was banned from usage, and over 25 years later many people are still unaware of the truth.

Let’s look at some of the facts. Early in this century, the only effective way to control malaria was to eliminate stagnant water, such as swamps and landfills, where Anopheles mosquitoes bred. Then beginning in 1943, the organochlorine pesticide DDT became available and this proved to be a godsend in the Third World, curtailing the disease dramatically. In India, by the early 1960s, the annual incidence of malaria had declined from one million to 100,000 (6) and in Sri Lanka, the number of cases dropped from over two million to 17 (7). In 1942 DDT was shown to kill body lice without adverse effect on humans, and it was used by all Allied troops during World War II. Thanks to DDT, a 1944 typhus epidemic in Naples was halted. No Allied soldier was stricken with typhus fever (carried by lice) for the first time in the history of warfare. In World War I, by contrast three million people died of typhus in Russia and Eastern Europe, and more soldiers died from typhus than from gunfire.

In 1962, Rachel Carson’s best seller, Silent Spring, Indicated DDT as a killer of birds, fish, and wildlife (9). This eventually led to a long (seven-month) federal hearing in 1972 on the risk and benefits of the material. The DDT hearings were ordered by then EPA administrator William Ruckelshaus, who appointed Judge Edmund Sweeney as the hearing examiner. Scientists were not the only ones to give exonerating testimony that DDT used properly presented little harm to humans, beast, or birds. The World Health Organization also pleaded at the EPA hearing that DDT was very beneficial in fighting malaria in many parts of the world and should not be banned (10). After 125 witnesses and 9362 pages of testimony, Judge Sweeney’s final conclusions were that:

DDT is not a carcinogenic hazard to humans
DDT is not a mutagenic or teratogenic hazard to humans
The use of DDT under the registrations involved does not have a deleterious effect on fish, estuarine organisms, wild birds, or other wildlife (7, 10).

In a better world this would have been good news. It was met instead with journalistic and environmental hysteria across the nation. Less than two months after the hearing, the EPA administrator Ruckelshaus single-handedly banned almost all DDT (8, 10). This ban on DDT was considered the first major victory for the environmentalist movement in the United States (11). It Gave credibility to pseudoscience, and created an atmosphere in which scientific evidence can be pushed aside by emotion, hysteria, and political pressure. This technique of making unsubstantiated charges, endlessly repeated, has since been used successfully against asbestos, PCBs, dioxin, and Alar to mention a few (7).

DDT was soon replaced by less persistent organophoshates, such as parathion and malathion. These chemicals belong to the same chemical family as nerve gas and are far more dangerous than chlorinated hydrocarbons such as DDT. They have caused serious poisoning, often fatal, among unsuspecting farm workers who had been accustomed to handling the relatively nontoxic DDT (6).

This ban didn’t help third world people. National Institutes of Health malaria expert Robert Gwadz says, “The legacy of Rachel Carson was not altogether positive. The incidence of malaria in India is now back up to more than a million and more than 500,000 in Sri Lanka” (6). In South America where DDT spraying has been continued until more recent times, data from 1993 to 1995 showed that countries that recently discontinued their spray programs are reporting large increases in malaria incidence. The only country in South America reporting a large reduction in malaria rates (61 percent), is Ecuador, which has increased use of DDT since 1993 (12, 13). The allegations against DDT have been repeated so often and stated with such passion that over 25 years later that the public remains convinced of their validity (14).

 

Toxicity of DDT

DDT is known to be safe to humans. It has never caused death, even in persons attempting suicide (15). Farm workers were sometimes poisoned by organophosphate insecticides, such as the parathions, which are hundreds of times more toxic to man than DDT and which were touted as superior substitutes to DDT (15). It is known from controlled studies in human volunteers that experimental ingestion of 35 mg DDT per kg of body weight per day, for a period of two years, produced no adverse effects, acute or chronic, in any of the subjects (5, 7). Doses of five grams of DDT (and even more) have been administered to human beings in the successful treatment of barbiturate poisoning, according to Walter Ebeling of UCLA. Professor Ebeling notes also that five grams of DDT are roughly four times as much as the average American will assimilate in a 70-year lifetime (16). A study of workers at the Montrose Chemical Company, who accumulated 38 to 647 ppm of DDT residues in their fatty tissues, revealed no cases of cancer in 1300 person-years of exposure – a statistically improbable event (17).

One of the more interesting examples verifying the nontoxicity to humans is the experience of J.G. Edwards, Professor of Biology at San Jose State University. Says Edwards, “After remembering my own days of dusting hundreds of civilians during the war in Europe with 10 percent DDT to kill lice and help prevent millions of cases of deadly typhus, I thought I should try to convince people that the environmental extremists were wrong. Thereafter, at the beginning of each DDT speech I made I would publicly eat a tablespoon of DDT powder. I believe it was a successful effort. It resulted in a full page photograph of me doing that in Esquire magazine (September 1971). The caption stated that I was eating 200 times the normal intake of DDT to show it’s not as bad as people think” (18). Today, as Edwards approaches his 80th birthday, he is still as adamantly opposed to the anti-DDT propaganda as he was 26 years ago. Edwards, an avid climber, continues to conquer peaks than 10,000 ft. DDT exposure surely hasn’t hurt him.

In 1969, rodent studies suggested DDT was a carcinogen. However, there results were refuted by a 1978 National Cancer Institute report that concluded, after two years, of testing on several different strains of cancer prone mice and rats, that DDT was not carcinogenic (11). In a 1994 study in the journal of the National Cancer Institute, researchers concluded that their data did not support an association between DDT and breast cancer (19). Very recently, Robert Golden, a Ph.D. toxicologist in Potomac, Maryland, stated, “The one endocrine modulator environmentalists love to hate, the pesticide DDT, would cause no endocrine effect in a fetus exposed to more than a pound of DDT over a course of a pregnancy” (20).

Bruce Ames and his colleagues at the University of California, Berkeley, have developed a method of ranking possible carcinogenic hazards (21).  They call this a HERP Index (Human exposure over rat potency). A value of 100 on this scale means that people are getting the same dose in mg/kg that caused cancer in half the tested rats. DDT has three major breakdown products: DDA, DDE, and DDD (18). Table 21.3.11 shows that the average U.S. daily intake of DDE from DDT (HERP = 0.0003 percent) is less than the HERP from chloroform in a glass of tap water and thus appears to be insignificant compared to the background of natural carcinogens in our diet. Even daily consumption of 100 times the average intake of DDE/DDT would produce a possible hazard that is small compared to other common exposures such as mushrooms, coffee, beer, and wine shown in Table 21.3.11.

Table 21.3.11 Ranking Possible Carcinogenic Hazards*

Possible hazard#

 

Human dose of rodent

HERP %

Daily human exposure

carcinogen

0.0003

DDE/DDT, daily dietary intake

DDE, 2.2 ug

0.001

Tap Water, 1L

Chloroform, 83 ug

0.1

Mushroom, one raw

Hydrazine mixtures

0.005

Coffee, 1 cup

Furfural

2.8

Beer, 354 ml

Ethyl alcohol, 18 ml

4.7

Wine, 250 ml

Ethyl alcohol, 30 ml

  • *From Ames and Gold (21).
  • # U.S. EPA’s one-in-a-million hypothetical risk is 0.000015 on the HERP scale, or about 400,000 times below the level that would give cancer to a rat.

 

Further support is provided by Stephen Safe, a toxicologist at Texas A&M, who tested the effects of organochlorine compounds in the average human diet. He concluded that the total estrogenic activity of these compounds is 40-million-fold lower than that from the natural components of vegetables and other foods consumed daily such as soybeans, barley, cabbage, and corn (20, 22).

 

Persistence in the Environment

One often heard claim is that DDT cannot be broken down in the environment. Actually, DDT is broken down rather rapidly by heat, cold, moisture, sunlight, alkalinity, salinity, soil micro-organisms, hepatic enzymes of birds and mammals, and a great many other environmental factors (18). Only in unusual circumstances where soil is dark, dry, and devoid of microorganisms will DDT persist. Under normal environmental conditions, DDT loses its toxicity to insects in a few days (7). If it didn’t break down, it would have been unnecessary to apply it again in order to control pests. Edwards provides a list of more than 140 articles documenting the breakdown of DDT in the environment (18).

A key reason that traces of DDT are sometimes still found in environmental samples is that we can now detect extremely minute amounts of anything. In the span of about two decades, detection limits have been reduced by about six orders of magnitude (23). Some analysts have even reported DDT in samples collected before DDT existed. For example, University of Wisconsin chemists were given 34 soil samples to analyze. They reported that 32 of 34 samples contained DDT. What the chemists didn’t know was that the soil samples had been hermetically sealed in 1911, and no DDT existed in the United States until 1940 (24, 25). The author wrote later: “The apparent insecticides were actually misidentifications caused by the presence of co-extracted indigenous soil components.” Still later it was found that red algae also produces halogen compounds that are misidentified as DDT by gas chromatography. Also, halogen compounds containing bromine or iodine, rather than chlorine, may falsely register as DDT on the gas chromatograph (26). Various PCBs were commonly misidentified are chlorinated hydrocarbon insecticides during the 1959s and 1960s, and were routinely reported as “DDT residues.”

 

Claims About Bird Declines

In Silent Spring, published on 1962, Rachel Carson stated that the American robin was on the verge of extinction (9). That same year, Roger Tory Peterson, America’s leading ornithologist, wrote that the robin was most likely the most numerous North American bird (18, 27). Carson’s notion that the most prolific bird was about to fall extinct was one of the most eye-catching assertions in Silent Spring and brought the book considerable publicity.

Peregrine falcons and eagles were also high on Carson’s list. In reporting on declines in population of these species she tended to heap the entire blame on pesticides and ignored all data that would refute her theory (16). Peregrine falcons were extremely rare in eastern United States long before there was any DDT present. By the time DDT was introduced there were literally no peregrine populations in eastern United States, but the anti-pesticide extremists later placed the blame on DDT anyway (18). Bald eagles in the lower 48 states were on the verge of extinction in the 1920s and 1930s, long before DDT was discovered. They were shot on sight for fun, bounty, or feathers, trapped accidentally, killed by impact with buildings and towers, or electrocuted by power lines. There is still high mortality because of the physical hazards, but much less to shooting and trapping (because if caught engaging in either activity you may now face a prison term). The most surprising thing is that the environmental industry and the news media continue to attribute the increase to just one thing – the 1972 ban on DDT (18). Continuing the saga of showing that DDT was not bad on eagles, a recent study at the University of Wisconsin at Madison Reported that lack of a suitable food supply in Lake Superior and, not DDT, was responsible for reproductive problems in eagles (28).

There was no mention at all in Silent Spring of the increases of birds observed by naturalists, including those participating in the Audubon Christmas Bird Counts. Naturalists counting hawks migrating over Hawk Mountain, PA, also reported great increases in the number of raptors, following the widespread use of DDT. Dr. J. Gordon Edwards, of San Jose State University, has documented those bird increases and also cited numerous feeding experiments that revealed DDT in normal bird diets did not cause the deaths of any birds (18, 26). Dr. William Hazeltine, another concerned California scientist, regarded pesticides as one of the least important causes of avian dislocations. The chief culprits, he said, were hunters, trappers, falconers, campers, and general encroachment of humans into nesting and feeding areas (16).

 

Bird Egg Shell Thinning

On close inspection even the oft-repeated eggshell thinning threat to bird life holds little validity. DDT opponents alleged then and now that DDT caused eggshells to be thinned/softened for certain types of birds, causing failure to hatch and populations to decline. Thin egg shells are a phenomenon that predates use of DDT. It’s been known for decades and there are many causes: diets low in calcium or vitamin D, fright, high or low daily temperatures, various toxic substances, and bird diseases such as Newcastle disease (7). It has been demonstrated repeatedly in caged experiments that DDT and its breakdown products do not cause significant shell thinning, even at levels many hundreds of times greater than wild birds would ever accumulate (26). The most notorious cause of thin eggshells is the deficiency of calcium in the diet. Some early researchers deliberately fed their birds only calcium deficient food (0.5 percent rather than the necessary 2.5 percent calcium) and then attributed all shell problems to the DDT and DDE they had added to that calcium deficient diet. Edwards reported that after much criticism about the use of calcium deficient diets that were known to give the false impression regarding DDT shell thinning, the tests with DDT and DDE were repeated, but with adequate calcium in the birds’ diet. The results proved that with sufficient calcium in their food the quail produced eggs without thinned shells (26).

Another method to obtain data is to measure the thickness of eggshells in museum collections. Measurements of the shells of hundreds of museum eggs have revealed that red-tailed hawk eggs produced just before DDT was used had much thinner shells than did eggs produced 10 years earlier. Then, during the years of heavy DDT usage, those hawks produced shells that were 6 percent thicker. Golden eagle eggshells during the DDT years were 5 percent thicker than those produces before DDT was present in the environment (26). More recently, R.E Green found that thrush eggshells in Great Britain were thinning by the turn of the century, 47 years before DDT hit the market. He speculated that the thinning may have been an early consequence of industrialization and that acids formed when pollutants belched out of coal furnaces and smokestacks may have changed soil and water chemistry enough to reduce the availability of calcium, which is critical in the diet of birds that are producing eggshells (29).

PCBs were later shown to cause dramatic thinning of eggshells, as well as other adverse effects on birds, yet environmentalists continued to place the blame on DDT despite the fact that feeding birds high levels of that pesticide did not cause them to produce thin eggshells. There are many environmental contaminants that do cause shell thinning. Oil, lead, mercury, cadmium, lithium, manganese, selenium and sulfur compounds have been shown to have adverse effects upon birds, including severe shell thinning (26).

 

Bioaccumulation and Biomagnification

“Bioaccumulation” refers to an increase in the concentration of a chemical in the environment (e.g., in water, sediment, soil.) “Biomagnification,” on other hand, refers to increses of chemicals as they are passed up food chains. As Ottoboni (5) points out, “The quantity of chemical that can be stored in any body can never exceed that which would be in equilibrium with the exposure. The chemical cannot remain in the storage depot without being replenished continually from the outside. Thus, the popular notion that foreign chemicals stored in a depot become immobilized and permanently fixed in the body, with additional exposure increasing the quantity stored ad infinitum, has no basis in fact. The claim that our bodies can become ‘walking time bombs’ is nonsense.” She sums it up best by pointing out that bioaccumulation in not inherently good or bad, but in the public mind it is considered, almost universally, to be the latter.

Biomagnificatiion proponents claim that pesticide levels are “magnified” at each step of food chain, for example, from algae to planktonic crustaceans to small fish to large fish to predatory birds or mammals. The consumption of low levels of pesticides within each prey animal is presumed responsible for increased amounts in higher predators (8). DDT is constantly broken down and excreted by the animals at each step of the food chain. If tiny crustaceans are analyzed, wet-weight, but the fish that ate them are analyzed dry-weight, the difference in the amounts of dilution by water creates an impression that the dry sample contains a greater amount of pollutants than the wet sample. DDT is attracted to fat tissues more than to muscle tissues, so comparisons between samples of these two types will indicate “magnification” into the fatty tissues, even if they are samples from the same animal. Likewise, brain tissues attract more DDT than fatty tissues. Anti-DDT activists were careful to measure crustaceans, wet-weight, and compare them with levels in dry-weight muscle samples in fish, dry-weight fatty tissue in ducks that ate the fish, and dry-weight fatty tissue in ducks that ate the fist, and dry-weight brain tissue in the hawks that ate the fish. If they measure ALL sample wet-weight, there is not “biomagnification.” (18, 26, 30).

 

Summary

There days a lot of effort is spent reminding people, particularly the younger folks, about the Holocaust and World War II because it’s now more than two generations since these occurred and people tend to forget. As Tenner (31) wisely says, “With each generation, part of the collective memory of the last terrible events is lost.” Well, it’s been over one generation since DDT was banned and clearly, most people today only speak ill of DDT. They have to clue about how valuable it was, nor the politics behind its banning. Speaking of holocausts, the banning of DDT was a holocaust. Malaria, which was being controlled by DDT, has proliferated since the abandonment of DDT. As Mooney (32) points out, this was an early example of western priorities being imposed on Third World people who may have made a different trade-off had the choice solely been theirs. Also, from Ottoboni (5), “The thought that substitution of nonresistant pesticides for persistent ones will solve all of the environmental problems attributed to the latter is am example of the myopic thinking that permeates so many decisions relating to environmental protection. People apparently haven’t realized that all nonresistant pesticides merely degrade to other chemicals! The only difference is that most of these new chemicals do not have the same pesticidal action as their parent chemicals.”

 

References:

  1. Richburg, K. B>, Out of American, BasicBooks, 1997.
  2. Access to Energy, Vol. 24, No. 12 (August 1997).
  3. Wirth, D.F., and Cattani, J., Technology Review, 100: 52, Aug/Sept 1997
  4. Gribble, G. W., “Environmental Issues,” Priorities, 10(2-3): 50, 1998.
  5. Ottoboni, M.A., The Dose Makes the Poison, Second Edition, Van Nostrand Reinhold (1997).
  6. Chase, A.S., Bugs in Environmentalism, S. J. Milloy, www.junkscience.com 1997.
  7. Ray, D. L., and Guzzo, L., Trashing the Planet, HarperPerennial, 1992.
  8. Flynn, L. T., “The Birth of Environmentalism, ” Issueds in the Environment, American Councial on Science and Health, New York, June 1992.
  9. Carson, R., Silent Sprint, Houghton-Mifflin, New York, 1962.
  10. Fox, M.R., “DDT Updated,” S.J. Milloy, www.junkscience.com, Washington D.C., August 28, 1998.
  11. Lieberman, A.J., Fact Versus Fear, American council on Science and Health, New York, Sept 1997.
  12. Roberts, D.R., Laughlin, L.L., Hsheih, P., and Legters, L.J., “DDT Global Strategies and a Malaria Control Crisis in South America,” Natiional Center for infectious Disease (July-Sept 1997).
  13. Roberts, D.R., U.S. Medicine, 34:36, March 1998.
  14. Wildavsky, A., But Is It True?, Harvard University Press, 1995.
  15. Mellanby, K., “With Safeguards, DDT Should Still Be Used,” Wall Street Journal, Sept 12,P. A26, 1989.
  16. Grayson, M.J., and Shepard, T.R. Jr., The Disaster Lobby, Follett Publishing Co., 1973.
  17. DDP newsletter, Vol. XIV, No. 3, May 1997.
  18. Edwards, J.G., Remembering Silent Spring and It’s Consequences, DDP Salt Lake City, Utah (August 3, 1996).
  19. Sturgeon, S.R., et al., “Geographic Variation in Mortality from Breast Cancer among White Women in the United States,” JNCI, 87, 1896, Journal of the National Cancer Institute, Dec 20, 1995.’
  20. Fumento, M., “Truth Disrupters,” Forbes, 162: 146, Nov 16, 1998.
  21. Ames, B.N., Magaw, R., and Gold, L.S., “Ranking Possible Carcinogenic Hazards,” Science, 236: 271, April 17, 1987.
  22. Safe, S.H., “Environmental and Dietary Estrogens and Human Health­­-Is There a Problem?” Environmental Health Perspectives, 103:346, 1995.
  23. Marco, G.J., Hollingworth, R.M., and Durham, W., eds., Silent Spring Revisted, American Chemical Society, Washington, D.C., 1987.
  24. McKetta, J.J., “Don’t Believe Everything You Read,” in Rational Readings on Environmental Concerns, Lehr, J.H., ed., Van Nostrand Reinhold, New York, 1992.
  25. Frazier, B.E., Chesters, G., and Lee, G.B., Pesticides Monitoring Journal, 4(2): 67, 1970.
  26. Edwards, J.G., “DDT Effects on Bird Abundance and Reproduction,” in Rational Readings on Environmental Concerns, Lehr, J.H., ed., Van Nostrand Reinhold, New York, 1992.
  27. Jukes, T.H., “The Tragedy of DDT,” in Rational Readings on Environmental Concerns, Lehr, J.H., ed., Van Nostrand Reinhold, New York, 1992.
  28. Milloy, S., Environment News, Heartland Institute, Chicago, Illinois, 2:9 Oct. 1998.
  29. Milius, S., “Birds’ Eggs Started to Thin Long Before DDT,” Science News, 153:261, April 25, 1998.
  30. Edwards, J.G., “The Myth of Food-Chain Biomagnification,” in Ratiional Readings on Environmental Concerns, Lehr, J.H., ed., Van Nostrand Reinhold, New York, 1992.
  31. Tenner, E., Why Things Bite Back, Alfred A. Knopf, New York, 1996.
  32. Mooney, L., “The WHO’s Misplaced Priorities,” Wall Street Journal Europe, August 25, 1997.

2007年03月7日 Posted by | 无法归类 | 留下评论

关于Inconvinent Truth

今天在牛博上看到这篇文章: 难以忽视的真相:An Inconvenient Truth, 看完了,觉得有些东西不吐不快,特别是对于我如此信任的牛博,我觉得有必要作一个提醒。

我在几个月前就看了这个电影,确实非常震撼,我对全球正在变暖这个观点也深信不疑。不过我跟小白并不信任戈尔这个人,因为在那时候,小白发现戈尔曾经给《寂静的春天》(”Silent Spring”)写过一个长序,并极力推广这本书。《寂静的春天》是一部充满了煽情语言的极端环保主义者的作品,它直接导致了人类对抗疟疾的最有效的药物DDT被禁用。而作者“Carson关于DDT可能致癌的断言到今天也找不到任何直接证据;而DDT是否导致她所提到的那些鸟类濒临灭绝也没有确切的科学证据。”《寂静的春天》中当然还充斥的其他没有科学根据的语言,不过DDT的被禁用,是这本书带给人类的最大灾难(若想知道更多关于《寂静的春天》和DDT,建议仔细阅读Silent Spring, DDT 以及世界卫生组织一篇文章并查找更多相关资料)。

所以我跟小白在看完电影之后,不得不查了一下相关资料,发现科学家们并不全部认同是由人类引起了全球变暖,而且戈尔在电影所表达的观点或者所引用的论据,科学家们也并没有一致认可。我认为这个电影确实应该推荐,不过不能用完全肯定的语气,至少我们应该告诉别人,不同的意见是存在的。比如“乞里马扎罗的雪不再壮观”,根据2004年《自然》杂志发表的一份研究显示,并不是因为全球变暖,而是当地森林采伐过度,导致当地空气湿度太低,降雪量下降(见AP INCORRECTLY CLAIMS SCIENTISTS PRAISE GORE’S MOVIE)。

若要知道更多关于这个电影里有误导人嫌疑的信息,可以先看一看下面这篇文章,An Inconvenient Truth-Gore as climate exaggerator。我尝试翻译了一个段落,是关于北极熊的。

“戈尔用一段动画,显示了一头令人同情的北极熊在海里游泳,希望能够找到最后一块在北冰洋上漂浮的冰块。在2002年,世界野生动物基金会发布了一份报告,警告全球变暖正在威胁北极熊(的生存)。北冰洋冰层的加速融化意味着在冰面上捕猎海豹的北极熊喂饱自己的机会将会更少。(我)在这周看到一个令人担忧的报告显示,饥饿的北极熊在猎食同类。不过,世界野生动物基金会的报告同时表明,大多数北极熊群的大小保持稳定,甚至有所增加(报告的第9页)。并且(我们应该)记住,北极熊在更暖和的6000年前,也好好的生活在北极。当然,若整个北冰洋将不再有冰的预言在100年后成真,那北极熊(的生存)就会有问题。”

我也认为全球变暖是一个事实,不过全球变暖主要原因是人类的活动还是我们正好处在两个冰川期之间,往变暖的方向发展,科学家们并没有定论。“The Earth is constantly in a state of flux either cooling or warming, but never static. Global Warming is better for mankind than Global Cooling. Mankind is not causing global warming due to carbon dioxide (CO2) emission. We are causing more sever damage to our environment and ourselves by other polluting efforts rather than our CO2 and water vapor emissions. These are scientific fact, and they are indisputable!”(来自“Global Warming and Al Gore’s Convenient Lie – Every breath you take is polluting?”的结论)

最后,这部电影煽情得有些夸张。若作为一部向观众介绍全球变暖证据的电影,并不需要如此煽情。用小白的话,作个结尾:因为煽情,所以至少是应该被怀疑的。

2007年03月3日 Posted by | 无法归类 | 一条评论