方舟子的Blog

载于《科学》2010年5月7日

（方舟子翻译）

最近一段时间以来对全体科学家、特别是气候科学家的政治攻击愈演愈烈，这让我们深感不安。所有的公民都应该了解一些基本的科学事实。科学结论总会有某些不确定性；科学永远不绝对地证明任何事情。当有人说社会应该等到科学家能绝对地肯定时再采取行动，这等于说社会永远不采取行动。对像气候变化这样的可能造成大灾难的问题来说，不采取行动会让我们的星球冒着危险。科学结论从对基本定律的理解推导而来，受到实验室实验、自然界的观察以及数学和计算机建模的支持。科学家像所有的人一样会犯错误，但是科学过程被设计了寻找并改正错误。这个过程本质上具有对抗性质——科学家享有声誉和获得认可，不仅是由于支持传统的学识，更是由于证明科学共识是错误的，存在着更好的解释。那正是伽利略、巴斯德、达尔文和爱因斯坦曾经做过的。但是当某些结论已经过全面和深入的检验、质疑和检查，它们就获得了“充分确立的理论”的地位，常常被称为“事实”。

例如，有确凿的科学证据表明我们的星球的年龄大约是45亿年（地球起源理论），我们的宇宙是在大约140亿年前的一次事件中诞生的（大爆炸理论），今天的生物都是从生活在过去的生物进化来的（进化论）。即使是这些被科学界普遍接受的理论，如果有人能够显示它们是错误的，仍然能够一举成名。气候变化现在已归到了这个范畴：有确凿、全面、一致的客观证据表明人类正在改变气候，因此威胁着我们的社会和我们赖以生存的生态系统。

否定气候变化的人士最近对气候科学，以及更令人不安地，对气候科学家的许多攻击，一般是由特殊利益或教条驱使的，而不是诚实地努力提供一个能令人信服地满足证据的另类理论。联合国政府间气候变化委员会（IPCC）和对气候变化的其他科学评估，有数千名科学家参与，产生了大量和全面的报告，也产生了一些错误，这是不出意料和很正常的。在错误被指出之后，就得到了改正。但是最近的这些事件丝毫没有改变有关气候变化的根本结论：

（1）由于大气层中温室气体浓度的增加，地球正在变暖。华盛顿一个多雪的冬天并不能改变这个事实。

（2）在过去的一个世纪这些气体浓度的增加大多是由于人类活动引起的，特别是由于燃烧化石燃料和砍伐森林。

（3）自然因素一直对地球气候变化有影响，但是在现在人类导致的变化影响更大。

（4）地球变暖将会导致许多其他气候模式的变化，其变化速度在现代是前所未有的，包括海平面上升的速度和水循环的速度都越来越快。二氧化碳浓度的增加正在让海洋变得更酸性。

（5）这些复杂的气候变化合在一起威胁着海岸社区和城市、食物和水供应、海洋和淡水生态系统、森林、高山环境等等。

世界科学团体、国家科学院和个人能够说的和已经说的要多得多，但是以上这些结论应该已足以表明为什么科学家担心后代将要面临的状况，如果人类所作所为一切照常的话。我们呼吁决策者和公众立即着手解决引起气候变化的问题，包括不受约束地燃烧化石燃料。

我们也呼吁，停止基于含沙射影和株连对我们的同事提出犯罪指控的麦卡锡式威胁，政治家为了避免采取行动借助骚扰科学家来分散注意力，以及散播关于科学家的赤裸裸谎言。社会有两种选择：我们可以无视科学，把头埋在沙中并希望我们有好运，或者我们可以为了公共利益行动起来，迅速和真正地减少全球气候变化的威胁。好消息是，聪明和有效的行动是可能的。但是拖延不可以是一种选择。

Science 7 May 2010:
Vol. 328. no. 5979, pp. 689 - 690
DOI: 10.1126/science.328.5979.689
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LETTERS
Climate Change and the Integrity of Science
We are deeply disturbed by the recent escalation of political assaults on scientists in general and on climate scientists in particular. All citizens should understand some basic scientific facts. There is always some uncertainty associated with scientific conclusions; science never absolutely proves anything. When someone says that society should wait until scientists are absolutely certain before taking any action, it is the same as saying society should never take action. For a problem as potentially catastrophic as climate change, taking no action poses a dangerous risk for our planet.
Scientific conclusions derive from an understanding of basic laws supported by laboratory experiments, observations of nature, and mathematical and computer modeling. Like all human beings, scientists make mistakes, but the scientific process is designed to find and correct them. This process is inherently adversarial—scientists build reputations and gain recognition not only for supporting conventional wisdom, but even more so for demonstrating that the scientific consensus is wrong and that there is a better explanation. That’s what Galileo, Pasteur, Darwin, and Einstein did. But when some conclusions have been thoroughly and deeply tested, questioned, and examined, they gain the status of “well-established theories” and are often spoken of as “facts.”

For instance, there is compelling scientific evidence that our planet is about 4.5 billion years old (the theory of the origin of Earth), that our universe was born from a single event about 14 billion years ago (the Big Bang theory), and that today’s organisms evolved from ones living in the past (the theory of evolution). Even as these are overwhelmingly accepted by the scientific community, fame still awaits anyone who could show these theories to be wrong. Climate change now falls into this category: There is compelling, comprehensive, and consistent objective evidence that humans are changing the climate in ways that threaten our societies and the ecosystems on which we depend.

Many recent assaults on climate science and, more disturbingly, on climate scientists by climate change deniers are typically driven by special interests or dogma, not by an honest effort to provide an alternative theory that credibly satisfies the evidence. The Intergovernmental Panel on Climate Change (IPCC) and other scientific assessments of climate change, which involve thousands of scientists producing massive and comprehensive reports, have, quite expectedly and normally, made some mistakes. When errors are pointed out, they are corrected. But there is nothing remotely identified in the recent events that changes the fundamental conclusions about climate change:

(i) The planet is warming due to increased concentrations of heat-trapping gases in our atmosphere. A snowy winter in Washington does not alter this fact.

(ii) Most of the increase in the concentration of these gases over the last century is due to human activities, especially the burning of fossil fuels and deforestation.

(iii) Natural causes always play a role in changing Earth’s climate, but are now being overwhelmed by human-induced changes.

(iv) Warming the planet will cause many other climatic patterns to change at speeds unprecedented in modern times, including increasing rates of sea-level rise and alterations in the hydrologic cycle. Rising concentrations of carbon dioxide are making the oceans more acidic.

(v) The combination of these complex climate changes threatens coastal communities and cities, our food and water supplies, marine and freshwater ecosystems, forests, high mountain environments, and far more.

Much more can be, and has been, said by the world’s scientific societies, national academies, and individuals, but these conclusions should be enough to indicate why scientists are concerned about what future generations will face from business-as-usual practices. We urge our policy-makers and the public to move forward immediately to address the causes of climate change, including the un restrained burning of fossil fuels.

We also call for an end to McCarthy-like threats of criminal prosecution against our colleagues based on innuendo and guilt by association, the harassment of scientists by politicians seeking distractions to avoid taking action, and the outright lies being spread about them. Society has two choices: We can ignore the science and hide our heads in the sand and hope we are lucky, or we can act in the public interest to reduce the threat of global climate change quickly and substantively. The good news is that smart and effective actions are possible. But delay must not be an option.

P. H. Gleick,* R. M. Adams, R. M. Amasino, E. Anders, D. J. Anderson, W. W. Anderson, L. E. Anselin, M. K. Arroyo, B. Asfaw, F. J. Ayala, A. Bax, A. J. Bebbington, G. Bell, M. V. L. Bennett, J. L. Bennetzen, M. R. Berenbaum, O. B. Berlin, P. J. Bjorkman, E. Blackburn, J. E. Blamont, M. R. Botchan, J. S. Boyer, E. A. Boyle, D. Branton, S. P. Briggs, W. R. Briggs, W. J. Brill, R. J. Britten, W. S. Broecker, J. H. Brown, P. O. Brown, A. T. Brunger, J. Cairns, Jr., D. E. Canfield, S. R. Carpenter, J. C. Carrington, A. R. Cashmore, J. C. Castilla, A. Cazenave, F. S. Chapin, III, A. J. Ciechanover, D. E. Clapham, W. C. Clark, R. N. Clayton, M. D. Coe, E. M. Conwell, E. B. Cowling, R. M Cowling, C. S. Cox, R. B. Croteau, D. M. Crothers, P. J. Crutzen, G. C. Daily, G. B. Dalrymple, J. L. Dangl, S. A. Darst, D. R. Davies, M. B. Davis, P. V. de Camilli, C. Dean, R. S. Defries, J. Deisenhofer, D. P. Delmer, E. F. Delong, D. J. Derosier, T. O. Diener, R. Dirzo, J. E. Dixon, M. J. Donoghue, R. F. Doolittle, T. Dunne, P. R. Ehrlich, S. N. Eisenstadt, T. Eisner, K. A. Emanuel, S. W. Englander, W. G. Ernst, P. G. Falkowski, G. Feher, J. A. Ferejohn, A. Fersht, E. H. Fischer, R. Fischer, K. V. Flannery, J. Frank, P. A. Frey, I. Fridovich, C. Frieden, D. J. Futuyma, W. R. Gardner, C. J. R. Garrett, W. Gilbert, R. B. Goldberg, W. H. Goodenough, C. S. Goodman, M. Goodman, P. Greengard, S. Hake, G. Hammel, S. Hanson, S. C. Harrison, S. R. Hart, D. L. Hartl, R. Haselkorn, K. Hawkes, J. M. Hayes, B. Hille, T. H?kfelt, J. S. House, M. Hout, D. M. Hunten, I. A. Izquierdo, A. T. Jagendorf, D. H. Janzen, R. Jeanloz, C. S. Jencks, W. A. Jury, H. R. Kaback, T. Kailath, P. Kay, S. A. Kay, D. Kennedy, A. Kerr, R. C. Kessler, G. S. Khush, S. W. Kieffer, P. V. Kirch, K. Kirk, M. G. Kivelson, J. P. Klinman, A. Klug, L. Knopoff, H. Kornberg, J. E. Kutzbach, J. C. Lagarias, K. Lambeck, A. Landy, C. H. Langmuir, B. A. Larkins, X. T. Le Pichon, R. E. Lenski, E. B. Leopold, S. A. Levin, M. Levitt, G. E. Likens, J. Lippincott-Schwartz, L. Lorand, C. O. Lovejoy, M. Lynch, A. L. Mabogunje, T. F. Malone, S. Manabe, J. Marcus, D. S. Massey, J. C. McWilliams, E. Medina, H. J. Melosh, D. J. Meltzer, C. D. Michener, E. L. Miles, H. A. Mooney, P. B. Moore, F. M. M. Morel, E. S. Mosley-Thompson, B. Moss, W. H. Munk, N. Myers, G. B. Nair, J. Nathans, E. W. Nester, R. A. Nicoll, R. P. Novick, J. F. O’Connell, P. E. Olsen, N. D. Opdyke, G. F. Oster, E. Ostrom, N. R. Pace, R. T. Paine, R. D. Palmiter, J. Pedlosky, G. A. Petsko, G. H. Pettengill, S. G. Philander, D. R. Piperno, T. D. Pollard, P. B. Price, Jr., P. A. Reichard, B. F. Reskin, R. E. Ricklefs, R. L. Rivest, J. D. Roberts, A. K. Romney, M. G. Rossmann, D. W. Russell, W. J. Rutter, J. A. Sabloff, R. Z. Sagdeev, M. D. Sahlins, A. Salmond, J. R. Sanes, R. Schekman, J. Schellnhuber, D. W. Schindler, J. Schmitt, S. H. Schneider, V. L. Schramm, R. R. Sederoff, C. J. Shatz, F. Sherman, R. L. Sidman, K. Sieh, E. L. Simons, B. H. Singer, M. F. Singer, B. Skyrms, N. H. Sleep, B. D. Smith, S. H. Snyder, R. R. Sokal, C. S. Spencer, T. A. Steitz, K. B. Strier, T. C. Südhof, S. S. Taylor, J. Terborgh, D. H. Thomas, L. G. Thompson, R. T. TJian, M. G. Turner, S. Uyeda, J. W. Valentine, J. S. Valentine, J. L. van Etten, K. E. van Holde, M. Vaughan, S. Verba, P. H. von Hippel, D. B. Wake, A. Walker, J. E. Walker, E. B. Watson, P. J. Watson, D. Weigel, S. R. Wessler, M. J. West-Eberhard, T. D. White, W. J. Wilson, R. V. Wolfenden, J. A. Wood, G. M. Woodwell, H. E. Wright, Jr., C. Wu, C. Wunsch, M. L. Zoback

* To whom correspondence should be addressed. E-mail: petergleick@pacinst.org
Notes
1. The signatories are all members of the U.S. National Academy of Sciences but are not speaking on its behalf.
2. Signatory affiliations are available as supporting material at www.sciencemag.org/cgi/content/full/328/5979/689/DC1.