2012-04-16 14:04:14 来源：光明网卫生事业部 贾志光 译 沈阳 校 查看评论 进入文化论坛 手机看新闻 10 发送给好友 http://health.gmw.cn/2012-04/16/content_3974839.htm !--enpproperty 39748392012-04-16 14:04:14.0贾志光 译 沈阳 校一份来自美国科学家就转基因增产神话的调研报告(1)_卫生频道_光明网转基因,美国,科学,产量,29222卫生原创/nodesearchname/enpproperty-- 2009年3月，这份由美国麻省理工学院科学家组织的专家格里安. 谢尔曼撰写的题为《 转基因 未能兑现的产量----转基因作物的性能评价》报告公布后，引起了全球、特别是美国公众的强烈反应，很多美国人这时才发觉，自已近40年来一直都被转基因产业大享所忽悠，因为大家最初支持转基因农作物研发，特别是听到了他们曾经承诺了一些十分响亮口号，包括：“转基因能最大限度地增产!” ，“转基因能解决全世界穷人的饥饿问题” 等等，我们把“ 科学家关注联盟 ”网站上的有关这份报告的介绍翻译出来，让有兴趣的朋友自己找出该报告去深入细读。我们也希望读者能把您的意见反馈给我们光明网卫生频道的同事，让我们共同关注全球转基因主粮的安全问题。小标题是译者所加。 一、《转基因未能兑现的产量》报告研究背景 多年来，转基因转基因生物技术产业以标榜能养活整个世界大肆鼓墟，并声称转基因作物会产生更高的产量。 格里安. 谢尔博士 由美国麻省理工学院科学家发起组织的“科学家关注联盟” 专家 格里安. 谢尔曼 (Doug Gurian-Sherman) 先生在2009年3月发布了题为《转基因未能兑现的产量》报告，认为以上这些转基因生物技术产业一贯标榜的承诺都是空谈：他用了美国近20多年的数据研究和13年转基因商品化了的资料分析，证明基因工程并不能够显著增加美国农作物的产量。 《转基因未能兑现的产量》是以农作物的产量作为指标仔细评估基因工程的整体效果的第一份报告，对比转基因与其他农业 科技 差异。报告综述二十几份玉米和大豆的学术研究资料，它们都是种植在美国的两种主要基因工程食物和作物。基于这些研究数据，《转基因未能兑现的产量》报告得出结论认为： *美国的基因工程种植的耐除草剂大豆和耐除草剂玉米产量并没有增加。而抗虫玉米只是稍微提高了产量。 *报告还发现：过去的13年美国的农作物产量的增加，很大程度上是由于传统育种和农业耕作技术的改进而带来的。 二、《转基因未能兑现的产量》报告主要结论 《转基因未能兑现的产量》报告提出时，正值全球食品价格暴涨和局部地区粮食短缺，国际社会关于如何促进农业生产力发展，提高产量呼声很高。 “产量”一词是指一个在特定时间内，每单位土地面积生产的农作物数量。转基因生物技术公司一贯认为要达到提高农作物产量这一目标，离不开基因工程的技术支持。 例如，孟山都公司正在全球传播的宣传广告，涉及世界人口爆炸问题的广告词说“......先进的种子能够显著提高作物产量......”。 《转基因未能兑现的产量》报告揭穿了孟山都公司这种广告词的说法，用数据证明：粮食生产要在未来增产，基因工程不起重要作用。 20世纪90年代中期以来，生物技术产业一直声称有更好的产量，但《转基因未能兑现的产量》阐述了实施于基因领域以提高产量的实验在20年中并无显著成果。 三、《转基因未能兑现的产量》的主要内容 1、区分“产量潜力”和“产量预期”概念 《转基因未能兑现的产量》报告还把农作物的“产量潜力”和“产量预期”这两个概念做了明确区分，它们常在行业中被混为一谈并被他人误解。 农作物的“产量潜力”是指在最好的生长条件下，作物的最终达到的生产量能力。而“产量预期”是指在排除病虫害，干旱和其他环境因素造成的损失后的产量水平。 2、三种转基因食品和饲料数据研究结论 《转基因未能兑现的产量》研究了美国三种最常见的转基因食品和饲料作物，即耐除草剂大豆，抗除草剂玉米，抗虫玉米（Bt玉米，在苏云金芽孢杆菌之后，其基因使玉米抵抗多种昆虫）的“产量潜力”和“产量预期”的数据，得出的研究结论是： 耐除草剂的大豆、抗除草剂玉米和Bt玉米未能增加内在产量。与传统方法相比，抗除草剂大豆和耐除草剂的玉米也没有提高经营产量。 该研究报告同时披露新发现的一个结论： 与典型的传统种植方法相比，Bt玉米在“产量预期”方面可能提高3-4%的边际产量。由于Bt玉米已经在1996年开始商品化，其产量每年只是平均增加0.2-0.3％。若以此数据做背景，美国过去几十年玉米产量平均每年都能增加约1％，这明显高于Bt基因性状提供的产量。 四、《转基因未能兑现的产量》的建议 《转基因未能兑现的产量》报告除了用历史数据评估美国基因工程外，还反思了该技术在未来几十年里可能增加粮食产量的潜在价值。 报告作者并不否认基因工程最终能有助于提高农作物产量。同时，报告也用数据告诉大家： 想借助基因工程技术支持去实现大幅增加农作物产量无实际意义，这一点对许多发展中国家而言十分重要。 此外，《转基因未能兑现的产量》报告也指出：最近的研究表明，尽量减少使用农药和化肥的有机质肥料，和类似的耕作方法已经令撒哈拉以南的非洲地区发展中国家贫困农民用低成本获得双倍作物产量回报。 《转基因未能兑现的产量》报告建议：美国农业部、美国的国家农业机构和大学要用为行之有效的方法，积极研究和开发农作物增产和提高作物产量的技术。这些方法应该包括： 现代传统植物育种方法，可持续发展的有机质肥料耕作农业，以及不需要农民支付大量前期种植成本投入的先进耕作方法。 该报告还建议，美国的粮食援助机构将这些有前途和低成本的农作物增产和提高作物产量的技术，传授给发展中国家农民使用。 格里安.谢尔曼说：“地球因人口过多和气候变化方面带来的饥饿问题，我们想找出解决办法并真正起作用，只能增加农作物的产量，而采用传统育种、耕作办法比转基因工程更有用。” For years the biotechnology industry has trumpeted that it will feed the world, promising that its genetically engineered crops will produce higher yields. That promise has proven to be empty, according to Failure to Yield, a report by UCS expert Doug Gurian-Sherman released in March 2009. Despite 20 years of research and 13 years of commercialization, genetic engineering has failed to significantly increase U.S. crop yields. Failure to Yield is the first report to closely evaluate the overall effect genetic engineering has had on crop yields in relation to other agricultural technologies. It reviewed two dozen academic studies of corn and soybeans, the two primary genetically engineered food and feed crops grown in the United States. Based on those studies, the UCS report concluded that genetically engineering herbicide-tolerant soybeans and herbicide-tolerant corn has not increased yields. Insect-resistant corn, meanwhile, has improved yields only marginally. The increase in yields for both crops over the last 13 years, the report found, was largely due to traditional breeding or improvements in agricultural practices. The UCS report comes at a time when food price spikes and localized shortages worldwide have prompted calls to boost agricultural productivity, or yield -- the amount of a crop produced per unit of land over a specified amount of time. Biotechnology companies maintain that genetic engineering is essential to meeting this goal. Monsanto, for example, is currently running an advertising campaign warning of an exploding world population and claiming that its “advanced seeds… significantly increase crop yields…” The UCS report debunks that claim, concluding that genetic engineering is unlikely to play a significant role in increasing food production in the foreseeable future. The biotechnology industry has been promising better yields since the mid-1990s, but Failure to Yield documents that the industry has been carrying out gene field trials to increase yields for 20 years without significant results. Failure to Yield makes a critical distinction between potential—or intrinsic—yield and operational yield, concepts that are often conflated by the industry and misunderstood by others. Intrinsic yield refers to a crop’s ultimate production potential under the best possible conditions. Operational yield refers to production levels after losses due to pests, drought and other environmental factors. The study reviewed the intrinsic and operational yield achievements of the three most common genetically altered food and feed crops in the United States: herbicide-tolerant soybeans, herbicide-tolerant corn, and insect-resistant corn (known as Bt corn, after the bacterium Bacillus thuringiensis, whose genes enable the corn to resist several kinds of insects). Herbicide-tolerant soybeans, herbicide-tolerant corn, and Bt corn have failed to increase intrinsic yields, the report found. Herbicide-tolerant soybeans and herbicide-tolerant corn also have failed to increase operational yields, compared with conventional methods. Meanwhile, the report found that Bt corn likely provides a marginal operational yield advantage of 3 to 4 percent over typical conventional practices. Since Bt corn became commercially available in 1996, its yield advantage averages out to a 0.2 to 0.3 percent yield increase per year. To put that figure in context, overall U.S. corn yields over the last several decades have annually averaged an increase of approximately one percent, which is considerably more than what Bt traits have provided. In addition to evaluating genetic engineering’s record, Failure to Yield considers the technology’s potential role in increasing food production over the next few decades. The report does not discount the possibility of genetic engineering eventually contributing to increase crop yields. It does, however, suggest that it makes little sense to support genetic engineering at the expense of technologies that have proven to substantially increase yields, especially in many developing countries. In addition, recent studies have shown that organic and similar farming methods that minimize the use of pesticides and synthetic fertilizers can more than double crop yields at little cost to poor farmers in such developing regions as Sub-Saharan Africa. The report recommends that the U.S. Department of Agriculture, state agricultural agencies, and universities increase research and development for proven approaches to boost crop yields. Those approaches should include modern conventional plant breeding methods, sustainable and organic farming, and other sophisticated farming practices that do not require farmers to pay significant upfront costs. The report also recommends that U.S. food aid organizations make these more promising and affordable alternatives available to farmers in developing countries. “If we are going to make headway in combating hunger due to overpopulation and climate change, we will need to increase crop yields,” said Gurian-Sherman. “Traditional breeding outperforms genetic engineering hands down.”
中科院大气物理研究所研究员刘骥平等人与美国科学家合作完成的最新研究发现，近几十年北极海冰减少对冬季降雪有重要影响。相关研究成果近日发表于最新一期的美国《国家科学院院刊》，并被选为新闻亮点文章。 对于近年来冬季的异常降雪和寒冷天气，一些学者认为是由北极涛动或厄尔尼诺造成。但刘骥平等人在论文中指出，北极涛动和厄尔尼诺不能解释过去4年出现的持续异常降雪和低温天气，北极海冰快速减少是导致近年来冬季极端降雪和严寒频发的重要因素。 此项研究表明，1979年以来，北极秋季海冰减少了29.4%，特别是过去4年是自有卫星观测以来的4个最小值。同时，过去的4个冬季，东亚、欧洲和北美大部分地区都出现了异常降雪和严寒天气。 结合观测资料分析和数值模式模拟，刘骥平等发现：一方面，夏季北极海冰的大范围减少以及秋冬季北极海冰的延迟恢复可以引起冬季大气环流的变化（这种环流变化不同于北极涛动），从而减弱了北半球中高纬的西风急流，使其振幅增强，即变得更具波浪状。这种环流变化使得北半球中高纬阻塞形势出现的频率增加，进而增加了冷空气从北极向北半球大陆地区入侵的频率，造成北半球大陆地区出现低温异常。另一方面，夏季北极海冰的大范围减少以及秋冬季北极海冰的延迟恢复使得北极存在更多的开阔水，从而将大量的局地水汽从海洋传输给大气。同时，北极的变暖也使得大气可以容纳更多的水汽。 上述两方面结合在一起，导致近年来东亚、欧洲和北美大部分地区冬季的异常降雪和低温天气。 该研究还指出，如果北极海冰继续减少，我们很可能会在冬季经历更多的降雪（特别是强降雪过程）和严寒天气。（来源：中国科学报 宗华） Impact of declining Arctic sea ice on winter snowfall renchunxiao 添加于 2012-3-5 15:55:15 125次阅读 | 0次推荐 | 1个评论 While the Arctic region has been warming strongly in recent decades, anomalously large snowfall in recent winters has affected large parts of North America, Europe, and east Asia. Here we demonstrate that the decrease in autumn Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation that have some resemblance to the negative phase of the winter Arctic oscillation. However, the atmospheric circulation change linked to the reduction of sea ice shows much broader meridional meanders in midlatitudes and clearly different interannual variability than the classical Arctic oscillation. This circulation change results in more frequent episodes of blocking patterns that lead to increased cold surges over large parts of northern continents. Moreover, the increase in atmospheric water vapor content in the Arctic region during late autumn and winter driven locally by the reduction of sea ice provides enhanced moisture sources, supporting increased heavy snowfall in Europe during early winter and the northeastern and midwestern United States during winter. We conclude that the recent decline of Arctic sea ice has played a critical role in recent cold and snowy winters. 作 者： Liu, Jiping; Curry, Judith A.; Wang, Huijun; Song, Mirong; Horton, Radley M. 期刊名称： Proceedings of the National Academy of Sciences 期卷页： 第卷 第期 ~页 学科领域： 地球科学 海洋科学 海洋地质学 添加人是否为作者: 否 原文链接： http://www.pnas.org/content/early/2012/02/17/1114910109.abstract?sid=30e91bdc-5224-4b0e-9cad-7778dc765487 DOI： 10.1073/pnas.1114910109 ISBN： 0027-8424
标签: 美国科学家
![[转载]美科学家首次实现中微子通信 有助与外星人联系](http://image.sciencenet.cn/album/201203/20/125742z7qztw77ywjdiqaz.jpg.thumb.jpg)
