Ecological network analysis: forgotten?

A new [preprint article](http://dx.doi.org/10.1016/j.ecolmodel.2009.07.012) pop up in *Ecological Modelling*'s RSS feed today, showing a case study using ecological network analysis in the functional assessment of an estuary ecosystem. I was wondering what is ecological network analysis, and how it assesses a system's function, so I read on.

It turns out that the technical details of ecological network analysis involves food web and information theory. The former I have some understanding, but the latter is too complex for me as a newcomer to dwell in the late night. [Here](http://www.fisheries.ubc.ca/files/ECOPATH%20IISoftwareForEcosystemModels%20_SmallerFileSize.pdf) is the paper describing the ECOPATH II model used by the preprint article. Judging from its number of being cited, many people must have used it successfully in their studies. However, the authors of the model acknowledged that it is based on a steady-state assumption, which arguably hardly exist in any real ecosystem, thus they recommend it used only in snapshot descriptions of ecosystems.

I doubt such a model can be used to describe ecosystem functions, considering that ecosystem functions do not present themselves in full in a "snapshot". The authors of the preprint article seem confident that this method at least identify ecosystem functions based on the goal of management defined by researchers and decision makers. But I think the role of artifacts and stochasticity in this is too significant to let pass.

In preliminary studies, I think this method has its use. If researchers can establish the food web structure and nutrient dynamics in a system, we may use this method to identify some key species or functions of the system. However, its results must be iteratively put back to our picture of the system, to check whether it conforms the dynamics and management goals. The method seems to work only with "pure" ecosystems, while many researchers have moved on to study social-ecological complex systems. I wonder if this is the reason why the method has been silent for all these years.

Christian, R., Brinson, M., Dame, J., Johnson, G., Peterson, C., & Baird, D. (2009). Ecological network analyses and their use for establishing reference domain in functional assessment of an estuary Ecological Modelling DOI: 10.1016/j.ecolmodel.2009.07.012

Christensen, V., & Pauly, D. (1992). ECOPATH II — a software for balancing steady-state ecosystem models and calculating network characteristics Ecological Modelling, 61 (3-4), 169-185 DOI: 10.1016/0304-3800(92)90016-8

Bodélé: "More or Less" a major dust source

Image via Wikipedia

Recently I am help doing a study on dust transport and deposition
concerning central and northern Libya. [A geochemical study](http://dx.doi.org/10.1016/j.atmosenv.2006.02.020) by my mentors suggest
that some of the dust in Hun and Sebha, even some in the coastal
areas, may be from the Bodélé, which is the largest source of dust in
Libya. [This preprint article on
PNAS](http://dx.doi.org/10.1073/pnas.0711850106), therefore, is of
special interest to me.

However, if the authors of the paper are right about the transport
mode of dust from Bodélé, our story may prove wrong. The authors
claim that the prevailing direction of the dust transport from this
area is towards the west in winter, which is also the maximum of dust
output in a year in the area. But our study area shows a constrasting
trend: lowest dust deposition both by ground data and remote sensing,
in winter, and it is to the north of Bodélé. The summer
transportation, if any, may contribute very little to our study area,
limited both by transport and production.

The MODIS brightness temperature difference (BTD) data is being
derived, which can provide us a picture of dust plumes for major dust
events. We are also looking at the geochemical properties and
meteorological data around the area. Combining these data, hopefully,
can provide more information on the transport mode in our study.

In the PNAS paper, the authors point out that the Bodélé area may be a
"tipping element" in the context of climate change, due to its
dominant position in the output of dust and its location. Some
climate models suggest that the area may become wetter, yet the wind
will be strengthened. As a result, it is really difficult to tell how
the dust output will be influenced by climate change at the moment.
Will we have more or less dust from Bodélé? This will be an
interesting problem, as dust from this area interacts with many
large-scale systems. It is a wonder, considering that the Bodélé
Depression is so small. The difficulty is that we only have inaccurate
model and incomplete data for this area, and for the North Africa.
New remote sensing technology such as
[SEVIRI](http://www.esa.int/esapub/bulletin/bullet111/chapter4_bul111.pdf)
(imagine quasi-MODIS resolution images every 15 minutes, very cool) may partly solve
the problem, but more geochemical and meteorological data are
essential to answer the complex dust question.

Washington, R., Bouet, C., Cautenet, G., Mackenzie, E., Ashpole, I., Engelstaedter, S., Lizcano, G., Henderson, G., Schepanski, K., & Tegen, I. (2009). Tipping Elements in Earth Systems Special Feature: Dust as a tipping element: The Bodele Depression, Chad Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0711850106

OHARA, S., CLARKE, M., & ELATRASH, M. (2006). Field measurements of desert dust deposition in Libya Atmospheric Environment, 40 (21), 3881-3897 DOI: 10.1016/j.atmosenv.2006.02.020

A modular tool for vulnerability study

The DIVA (Dynamic and Interactive Vulnerability Assessment) tool is a modular "discussion-making" tool developed by the EU funded [DINAS-COAST](http://www.dinas-coast.net/) project. The tool is used to facilitate the assessment of vulnerability in coastal areas. It tries to address these drawbacks of similar tools and models:

* Low resolution and obsolete data sources;
* Limited number of scenarios;
* Unable to identify causes of vulnerability except for sea-level rise;
* Not considering social-nature interaction and feedback;
* arbitrary and simplistic assumptions about adaptation.

The main characters of the DIVA tool are:

* Integration of multiple disciplines in the study and simulation of vulnerability issues;
* Modular architecture allows constant update and evolution of the tool, to adapt to changing contexts and adaptation/succession;
* Non-expert friendly interface, designed to help answer questions asked by stakeholder and researchers from a wide range of groups.

Using a relational geospatial information database as its foundation, the DIVA tool can be considered as a set of modules, each addressing a process contributing to the vulnerability of coasts, governed by a framework that describes the conceptualization of the system in question. Only processes that conform to the general conceptualization can be modelled.

The development of the tool is an interesting case study of distributed software engineering. The authors of the modules belong to different institutions all over the Eurasia continent, and collaboration has to be carried out with email, Internet and phone. During development, the developers cannot even tell what the interfaces of the modules would be. To coordinate the efforts, the whole consortium used an ontology (conceptualization) of the system, and stored it as XML in a central location. The ontology then guides developers to establish algorithms and data structures. The module then goes to a stand-alone mode test. Finally, the linkage of the module with others and the whole model are tested.

Judging from the difficulties of developing such a complicated project, the DIVA tool is an exceptional success. However, the modular approach also have its own problems. The most significant one is that one module's underlying theory and implementation are often not concerned by other experts, and the relationships between modules are not always well understood. This perhaps is why the author of [the article](http://dx.doi.org/10.1016/j.gloenvcha.2009.03.002) calls the DIVA tool "transdisciplinary" instead of "interdisciplinary".

An important issue in vulnerability studies is [the cross-scale interactions](http://dx.doi.org/10.1191/030913200701540465). The DIVA tool cannot address this issue well, but the authors are pretty sure that the modular structure of the tool allows these features to be easily added. It is natural to consider the possibility to expand the tool to other vulnerability problems, such as desertification or energy dependency, but this may need a new framework. It is also not clear whether the DIVA framework supports modelling of long-range interactions.

The authors do not expect the DIVA tool to answer all vulnerability questions. They call it a "discussion-making" tool instead of a "decision-making" tool. The ability to better incorporate stakeholders in vulnerability study is eagerly needed in all kinds of socio-ecological systems. It would be wonderful to see more DIVA-style tools appear.

Hinkel, J., & Klein, R. (2009). Integrating knowledge to assess coastal vulnerability to sea-level rise: The development of the DIVA tool Global Environmental Change, 19 (3), 384-395 DOI: 10.1016/j.gloenvcha.2009.03.002

Adger, W. (2000). Social and ecological resilience: are they related? Progress in Human Geography, 24 (3), 347-364 DOI: 10.1191/030913200701540465

Ocean acidification below the surface

The climate change deniers say that climate change and relevant concerns are a fad. Well they must be wrong. From my personal experience I was reminded of [the climate change scenario](http://www.jstor.org/action/doAdvancedSearch?q0=global+warming&f0=all&c0=AND&q1=&f1=all&c1=AND&q2=&f2=all&c2=AND&q3=&f3=all&wc=on&sd=1980&ed=1989&la=&jo=&Search=Search) in 1980s -- right, before I went out of the kindergarten -- and that was like 20 years ago. And scientists today are using data that are accumulated continuously in the past 20 years to study the impact of climate change.

One instance is this [preprint](http://www.pnas.org/content/early/2009/07/24/0906044106.abstract) published on the PNAS website. The authors creatively used the fixed-temperature pH data, avoiding problems like the change of H₂CO₃ equilibria with temperature, and making the seasonal trend pronounced. It is pointed out that there is a trend of decreasing pH at sea surface, and more importantly, the seasonal pattern of water change between surface and sub-surface zones of the ocean may be a profound factor in a more complicated ocean acidification picture.

There are drivers at different scales at play here, causing diurnal, seasonal and annual variabilities of the ocean acidity. The authors mentioned a strong pH negative anomaly in 1998, which causes me to think whether there could be some cross-scale interactions, such as El Nino, also at play.

Another thought that occurred to me is that the dissolved organic carbon may be a slow variable in the ocean system. Of course I am not an oceanographer and this is just a wild guess. But if there is any oceanographer reading, would you care to explain the circulation of inorganic carbon in the ocean? We all know the acidity in the ocean is slowly increasing, but if there is an accumulation process of inorganic carbon that we do not know, one day it is going to give us a bigger surprise given adequate temperature and mixing conditions.

John E. Dore, Roger Lukas, Daniel W. Sadler, Matthew J. Church, & David M. Karl (2009). Physical and biogeochemical modulation of ocean acidification in the central North Pacific Proceedings of the National Academy of Sciences of the United States of America DOI: 10.1073/pnas.0906044106

What is truly adaptive management?

Folke et al. (2002) argued that active adaptive management can help resilience-building in social-ecological systems. Active adaptive management, by their definition, considers policy as a set of experiments designed to reveal underlying processes that build or maintain resilience. They pointed out that to achieve active adaptive management the managing institution should be open and flexible governance bodies that can "learn, generate knowledge and cope with change".

In real life scenarios, the problem with active adaptive management is what should the decision makers and stakeholders learn from the experiments and what kind of institution is really "adaptive".

[A new article](http://dx.doi.org/10.1016/j.gloenvcha.2009.06.001) appearing in Global Environmental Change is another attempt to tackle these questions. The author argues that often policies are not adaptive in that they are just trying to adjust actions according to the effect, without further questioning the underlying constraints and contexts of the action. To be adaptive and help build resilience, the governing regime should adopt multiple levels of learning, starting from refinement of actions, to questioning the frame of reference and underlying assumptions, to transform the structure of context and established values and norms. If the institution is only limited to the first loop of learning, it may finally encounter some restraints that limit its adaptive capacity. As a result, in the face of larger environmental or socioeconomic changes the institution will fail to maintain the resilience of the complex system.

The author further points out that a government-dominated institution would not be flexible enough to adopt the second- or third-loop learning, which requires the change of the whole actor network, regulations and the structure of the institution. As a complement of the "formal" institution, the "informal" institution featuring stakeholder participation, more flexible regulation, and local knowledge should be introduced. It is noted that such kind of informal institutions often lack a voice or ability to take actions in large-scale projects, thus a hybrid institution combining the executive power of formal institutions and the flexibility of informal institutions is called for.

The trend of more active informal network, or "shadow network", may see the hierarchy in environmental management more diminished. How to guarantee the voice of the informal institutions heard may not be a major problem in industrialised countries, but will be one for minority groups and marginalised communities in developing countries. To establish a context around their point of view will be an interdisciplinary challenge.

Claudia Pahl-Wostl (2009). A conceptual framework for analysing adaptive capacity and multi-level learning processes in resource governance regimes Global Environmental Change, 19 (3), 354-365

Carl Folke, Steve Carpenter, Thomas Elmqvist, Lance Gunderson, C S Holling, & Brian Walker (2002). Resilience and Sustainable Development: Building Adaptive Capacity in a World of Transformations Ambio, 31 (5), 437-440

北美蝴蝶物种多样性的统计研究

今天在学校听了来自 UC Irvine 的 [Bradford A. Hawkins 教授](http://www.faculty.uci.edu/profile.cfm?faculty_id=4562)的一个讲座。 据说Hawkins 是生物地理学和宏观生态学方面的大牛，可惜听讲前自己没有做足功课，虽然讲座是近期少见的信息量大、富启发意义的题目，却没有听得太明白。 好在回来搜论文找到了 Hawkins 等即将发表的关于同一个研究的[论文](http://dx.doi.org/10.1111/j.1365-2699.2009.02119.x)。

Hawkins 等人使用了墨西哥以北的北美地区夏季和冬季的蝴蝶物种丰度资料，将蝴蝶亚科按照分布范围分成热带和非热带两部分进行讨论。从物种丰度在纬度方向上的梯度看，热带类型的蝴蝶物种明显地表现出夏季向北迁徙或者 recolonize 的趋势；而非热带类型的蝴蝶则很少表现出有长距离的迁移。而以亚科在包括弄蝶总科 Hesperioidea 和凤蝶总科 Papilionoidea 的整个谱系树上的遗传距离（Mean Root Distance, MRD）来看，北美地区靠近热带的南部物种间的距离较短。 如果蝴蝶起源于热带的假设成立，这说明非热带物种多是适应了较寒冷气候的进化支。

根据对 8 个可能因素的回归分析，热带物种的丰度跟温度正相关，与热带地区的距离成负相关。非热带物种丰度与温度的关系更复杂一些。虽然夏季温度还是与物种丰度正相关，冬季温度较高的地区物种丰度却不一定更高。作者提出的解释是对于适应了较寒冷环境的蝴蝶物种，冬季温度有一个最适范围，高于这个范围的温度可能会扰乱休眠期的蝴蝶的生理活动，导致其数量减少甚至局部灭绝。一些对北半球气候变化造成的物种向北迁移的现象可以作为这个观点的一个注脚。

作者在文末指出形成北美蝴蝶多样性梯度的根本原因在于蝴蝶的热带起源和第三纪中期以来的长期气候变化模式。Hawkins 今天在讲座中进一步指出在欧洲、澳大利亚、智利、南非等地区也都发现了类似的梯度分布，可见他的观点具有相当强的解释力。这一研究不仅能用来解释北美现有的蝴蝶多样性梯度，也有可能被用来进一步研究蝴蝶各亚科和物种的进化和迁徙模式。这种研究方法理论上说也应该可以应用于其它起源于热带的物种，但对于蝶科的生活史、习性和物种分布的完整研究是做出这样研究的前提条件，不知道在无脊椎动物中还有哪些物种有这样完整的研究记录。

这一研究也揭示了气候变化引起的冬季温度变化将会给非热带蝴蝶物种带来的问题。从北美地区来看，热带物种可能不会仅仅因为温度上升就迁往更朝北的地区，但非热带物种聚集的地带可能会向北移动，欧洲也是如此，甚至有可能在热带和非热带物种区之间形成一个空白地带，也许会对这些地区的农业和林业产生影响。

Hawkins, B., & DeVries, P. (2009). Tropical niche conservatism and the species richness gradient of North American butterflies Journal of Biogeography DOI: 10.1111/j.1365-2699.2009.02119.x

Capturing cross-scale interactions

People studying ecological resilience talk about cross-scale interactions a lot. Yet people often claim that cross-scale interaction is in play without quantitative evidence. [Researchers from Argentina](http://dx.doi.org/10.1007/s10021-005-0091-9) in 2005 proposed to use regression on data sets collected in different years to identify the existence of cross-scale interactions.

The approach cannot tell what really is cross-interacting with other variables, yet. And being a statistical method, it requires a huge amount of data. Perhaps by regression of multiple series and types of data, and with the aid of conceptual models, this approach can bring more insight into the system.

倒倒苦水

这篇本来要发豆瓣日记的，结果“本功能暂停使用”。

最近在医师的指导下用认知行为疗法治疗自己的 low self-esteem 和一系列相关问题。今天看到[这样](http://www.douban.com/review/2129677/)的一篇评论，我就想我的无力感和自卑是不是有一部分要归功于这样的观点和那些气候变化否定论以及气候变化人因否定论以及气候变化人类干预有效否定论啊。这些人怀疑个人对环境有什么影响；我怀疑我个人写的这么一篇回复对ta们能有什么作用，久而久之就感到万分沮丧，甚至开始怀疑人生……

作为一个学环境出身的人，看到人物理学家说个“场”字都被民科们争相引用，人天文学家说冥王星不是行星它就不是了，我们搞环境和气象的在学科内部有争议也就算了，学科内达成基本一致的结论，拿出来却要被政客忽略，被公民误解，被否定论者歪曲……心里真有些不平。

至少在豆瓣上，多数人是在找各种各样的理由想办法把“难以忽视的真相”过滤掉的，少数人是搅浑水的，更少数人是感到痛心的。

下次看见类似的评论，哪怕口水嚼成丸药，还是会写东西反驳，哪怕没有人看，哪怕得罪人。

一个半路出家的地理研究僧之杂感

[caption id="" align="alignleft" width="300" caption="Image via Wikipedia | 1915年的《国家地理杂志》，这时的地理学还是以特例式的叙述为主"][/caption]

[caption id="" align="alignright" width="300" caption="Image via Wikipedia | 21世纪的《国家地理杂志》，封面故事反映了对自然资源和人类社会的同等关注，也反映了地理科学的发展"][/caption]

几天前我向导师提出了一个盘踞自己心头已经很久的疑问：我从本科到研究生到博士生阶段，分别都是学的不同的东西，结果我没法说自己精通任何一门学科。如果要走学术道路的话，这样是不是太不妥当？我的这种感觉在试图找工作时尤为强烈，因为我既不能说我自己熟悉遥感应用，也不能说我长于环境工程，甚至即使要谋一个教职也不好意思说自己是学地理出身。跟很多一直从事一个领域的工作并最终成为专家的人相比，我觉得我的问题在于选择学习方向时太随遇而安，只要学校给 admission 我就去学，结果貌似已经没有成为专才的可能了。

不过按导师的说法，这正是地理这个学科的特点。导师自己是学地质学出身，当年带着小锤子敲石头做出来的本科论文还在办公室里放着，后来又改搞河流研究，而从我认识她到现在我一直以为她是个专业的人文地理学家。她可以早上写关于经济地理学的论文，下午跟人讨论怎样开展沙尘的研究。说到这里她说我也同样可以办到（好吧我也是这么觉得的）。作为一个所谓的多学科研究者，自己有什么不懂的东西，总可以通过向各领域的专家学习来弥补，一样可以解决实际研究中的问题。而地理学科本身也是不断地与其他学科交叉融合的，从这个意义上说，没有狭义上的地理学“专家”，每个地理学家都只能说自己对某一方面问题比较了解。当然，授予专家的诺贝尔奖基本与地理学家无缘了，虽然如果ta们放下学术去搞政治或者慈善，还有拿个和平奖的可能。

在地理这个学科环境中浸泡得越久，我就越觉得难以对地理究竟是学什么和研究什么下一个准确的定义。殖民时代的西方地理学是对大地形态的描述，但不久之后地理学家们游记性质的记述中就加入了对风俗人情的描述，这也许就暗示了人文和“自然”地理的不可分割。自然地理的距离、梯度等概念往往是各种社会网络形成背后的原因，而人类长期以来对自然界的影响又往往被社会的制度以及经济因素所决定。地理学究竟是何时分裂成自然和人文两大分支，很难考证。但至少我可以有把握说，不存在无法从人文社会知识中吸取养分的一流自然地理学家，反之亦然。近年来在地理学科中对跨学科研究的重视，以及自然/人文地理交叉形成的环境地理学的出现，可以印证我的这一观察。实际上，如果不考虑个人的精力有限，才能各异，导致其必然在研究中稍微偏向自然或人文方向，学地理的人给自己加上“自然”或“人文”的标签并没有太大必要。不加标签，也许还能够不带偏见地看待地理学科长期积累的财富，选择切入课题的最佳角度和方法。

虽然地理学的研究一直要借助其他学科的研究成果，而且地理学的自然和人文分支的界限越来越模糊，但这并不说明地理学只是其他学科研究的简单堆砌和组合。地理有自己的一套阐释地理现象的思路。我自己是半路出家，只能说对这套思路有些感觉，但觉得还没法很全面和准确地概括其特点。我的感觉是地理学鼓励人们用综合的方式看问题，研究者可能从某种土地利用类型的分布出发，纵向看其历史变迁，横向论其对社群和自然环境的影响，或许更进一步，联系社会学的理论讨论其更为深广的社会、经济甚至意识形态的意义。这一点从英美教育系统的地理学科课程设置也能体现出来。而且与许多学科年级越高，专业越窄的发展趋势不同，地理学科中从本科到硕士到博士，毕业论文对涉及问题不仅深度要求更高，还要求高阶段的研究者能从更广泛的信息来源综合形成对一种地理现象的较全面的阐释。这种综合研究并不是很容易做好的，而且在外人看来确实容易形成东拉西扯的印象，这也许是地理学有时会被怀疑只是一种叙述体裁和技术而非科学的原因（当然还有 -graphy 这个词根惹的祸）。

我对自己最近的研究，觉得在综合讨论问题方面做得还可以，但是不知道论文是否真正地反映了一种“地理学的观点”。毕竟我没有读过多少地理学的经典著作，对关于我研究区域的地理著作的接触更少。目前看来我的导师与我的一个意见分歧就是她要求我把过去在研究区域旅游的经历作为论文方法的一个组成部分多展开一些，因为这是实地经验的一部分。但我始终没法接受这种写法，或者说不知道该怎么把这部分整合到一篇以数学公式和遥感图像为主的论文中去。如果我从本科开始接受比较系统的地理教育，也许在这时候的情况就会有所不同。从个人的角度说，从专才教育开始接触地理，更有好处一些，例如对地理学自身的各种理论和方法能更系统地掌握，更清楚它们的优点和局限，同时写出来的东西会是典型的地理研究而较少有成为四不像的危险。但从整个学科发展的角度说，从别的学科接触地理，更有助于为这个学科提供新的思路。当代有名的地理学家当中，固然有不少是从本科开始学习地理的科班出身，但也不乏从气象学甚至工程背景中成长起来的，后者往往带着ta们的背景来研究地理问题，最终提供了新的方法和视角，甚至改变了学科的面貌。

从出口的方向上说，地理学给人的印象是在具体生活中应用有限，甚至连规划这样本应该由地理系学生挑大梁的工作，也往往是由建筑专业或者土木工程专业占主导地位。除了遥感和 GIS 方向以外，政府和企事业单位中学地理的人占有优势的岗位似乎相当之少。地理从一门描述性的学科转变为科学以来，层出不穷的理论的抽象性固然限制了它的实际应用，但今天的局面并不全然是地理学科自身的问题。国内的地理系多见于二、三线的大学，甚至高专，有些甚至都不算是独立的专业。除了遥感和 GIS 专业以外，学地理唯一的出路似乎就是去当中小学的地理老师，教孩子们早已过时的叙述式的殖民主义地理。而地理科学实际上的应用，分散在经济、建筑、环境等不同的专业当中。这种设置也许也能培养出地理学的人才，只是ta们带着经济学家、规划师或者环境工程师的头衔，而不知道自己所受的来自于地理科学的教育对自己究竟帮助几何，也不知道自己实际上可以为地理科学做出贡献。虽然这是国内多年来的现状，但我以为这是不合理的，特别对地理科学是不公平的。地理学之所以被看作是没有实用价值，只能在象牙塔里呆下去，恰恰是因为象牙塔里没有给地理学一个合适的位置。一个独立的地理科学系（注意不是往往以地质学和地球物理为主或者太偏重自然科学的地球科学系）不仅能为生态、环境科学、规划科学等专业输送跨学科人才，更重要的是原来分散于这些专业中的地理研究可以集中起来，互相借鉴，地理科学因而能得到更好的发展。相辅相成地，为数众多的自然、社会和人文学科也可以从中受益。在学科交叉成为趋势的今天，一个独立的，研究范围广泛，同时与其他专业保持活跃人才和知识交流的地理系，将可以成为一个重要的人才培养平台。

嗯好吧如果我在教育战线上混出来了就争取建立一个这样的地理系。

Can Fairtrade be more fair?

Image via Wikipedia

First, I need to point out that this is a really quick post, I haven't done much research as it is late in the night and I don't have much time on this one. So if there is anything you think is unfairly biased or plainly wrong please do point it out in comments, I would really appreciate that.

This article begins as a quick thought during one of the tutorial group discussions of which I am in charge. We were discussing about the globalisation of production and the topic shifted to Fairtrade and their practices in developing economies. I asked one of my tutees that why Fairtrade does not set up factories in the area where they grow coffee and bananas etc., to better help local farmers? Her guess was that this may introduce unwanted environmental impact and damage to local culture as well. I was not totally content with this answer although I think this is a brilliant enough answer for a first year student. Environmental impacts can be assessed and controlled; cultural invasion and mingling is happening anyway; but local people have the rights to have better life and more opportunities in international competitions. This calls for better institutions and infrastructure, which does not happen merely by sending in more money like Fairtrade does, as proved by Chinese experience in our poverty reduction campaigns.

The current world production pattern of extracting raw materials from developing economies, produce them in countries with cheap labour, under the command of offices from developed countries, and sold worldwide is determined to a quite large extent by colonism history and capitalism world economy. Comparing developing economies in Asia and Africa or South America, especially between countries like South Korea, Singapore and countries like Bolivia and Ghana. They were all exploited in 19th and early 20th century, and reached independence at about the same time, why the Asian countries are walking into modernization with established legal and political institutions and greatly improved livelihood while their African and Latin American counterparts are stilled bogged by corruption, lack of education and low industry output? One of my tutees brilliantly suggest that these continents are being exploited in different manners. In Asia, for some reason the labour resources are what the colonizers seek about, while in Africa it is largely natural resources. Thus Asia enjoys establishment of manufacture industries while only resource extraction industry was available in Africa and South America when they reach independence. On such different base, the different paths of development and continued being exploited were determined.

Although not sounding political correct, I think this is an interesting theory, I don't know if scholars mentioned it in their works already. In the following discussion we identified more factors contributing to different development levels: skill of workers, education, social institutions, technology, and transportation. The role of the last is pronounced in the difference between North Africa and central African countries, thanks to the former's developed transportation system and advantage of Mediterranean Sea. In a word, these things are one thing all development workers seek to build: capacity to develop further. Pay more to coffee-picking farmers is good, but without another forces to build capacity, the farmers would have no place good to invest their income, and further change won't take place.

Yes, I believe by setting up local factories by Fairtrade and export to Europe chocolate bars instead of fermented chocolate seeds will help local people better. Technology can be spread to these economies, and local people won't have to buy from, say, Nescafe, and be exploited for a second time (the first when Nescafe buys from local warehouses). Why this did not happen? Again I think it is the almighty economy at play here. One reason I can think of is that the chocolate has to be exported to areas with sufficient purchase power, say Europe, yet the strict standard used to protect its people from bad food would make the cost of setting a factory in the Fairtrade partner country so prohibitive that it is simply not feasible economically.

How to deal with this problem? Again quick but surely far from perfect answer: as part of the international or multinational firms' social responsibility, they need to invest a portion of their sales income in helping the country of source and Fairtrade develop infrastructure and education of workers. When the condition is met a local factory should be established, meeting environmental requirements and managed by local staff. Firms like Nescafe do [set factories](http://www.nescafe.com/NR/rdonlyres/CA26CACB-CE8A-4F5A-BCFF-8C908DF55B77/67164/whatcanbedone1.pdf) in ``developing countries'', however to what extent this has helped knowledge and skill transfer is absent from their report.

Are mustangs merely horses?

Image via Wikipedia

I just finished this month's issue of National Geographic Magazine and find, among other interesting or informative articles, a [story](http://ngm.nationalgeographic.com/2009/02/wild-horses/fuller-text/1) about mustangs in America's Old West especially thought-provoking. The article mourns about the shrinking habitat for mustangs ("wild horses" or feral horses) and possible loss of a valuable animal (I would reserve in saying it unique) and the spirit behind it.

The preservation of mustangs in my opinion has a larger symbolic purpose rather than a biological or ecological one. As pointed out in the NG article, the mustangs may very likely be the descendant of horses brought by Spanish *conquista* c. 1519. Genetically they may have little or none difference from the original Iberian species or other domestic species produced in the U.S. later. Preserve mustangs therefore is saving meme instead of saving gene, which is rare practice in animal conservation. Considering the huge investment in the conservation of mustangs, I think I have the right to ask as a by-stander: why don't the U.S. put the money to some better conservation use?

The difficulty in conservation lies in mustang's impressive ability to reproduce and extremely limited "wild" habitats nowadays. The authorization did what they can to control the total number of mustangs in the wild so as to make sure they do not graze the grassland into deserts and themselves to death. But this is criticized by people for reducing viability of the wild population. Some other people say that the population should be taken care of by Nature, to live the way they are supposed to be. However, such romantic imagination of Nature may not work in reality, as the habitat is so small and fragmented. All these creates a typical dilemma if you insist that mustangs are indeed a distinctive species that needs protection. Defeatist as it may sound like, I think feral horses should be left by themselves like feral dogs, and [euthanized](http://abcnews.go.com/Technology/AmazingAnimals/wireStory?id=6261967) in a controlled manner if necessary.

Image via Wikipedia

All this talk because mustangs are not genetically distinctive to be called as a species. On the other hand, it may sound tyrannical, even unethical, to judge an animal's conservation value merely by their genes. As a population, mustangs do have their culture values that cannot be replaced by purely domestic horses, despite their identical genes. This is just like the value of most human populations is not their genetic uniqueness, but their culture. But to extend the analogy a bit further, we can easily find that the unsuccessful strategy used to conserve mustangs is deemed to be a failure just like such a strategy used to protect a culture. You cannot protect a human population by taking samples from them regularly and put them in a so-called reserved area. The only way for a mustang or human population to be viable is to guarantee them the way of life they are used to and deserve. Different from protecting a human population, it is ethical and necessary to cull existing mustang population and re-introduce their predators into the wildness of the west. As it was mankind who broke the coyote/wolf-horse equilibrium out of balance, now mankind also have the duty to re-introduce the equilibrium, or at least create a human-horse equilibrium, i.e. artificially control mustang population. Failing to do that, all efforts to preserve mustang population and culture would be self-defeating.

To make the equilibrium happen, and to serve other many important ends, it is of paramount importance to conserve a valid wildness. It may not be free from human interference, but should be able to support a viable wild horse population and the ecosystem they are in. Indeed, the need to preserve mustang culture can be itself an emotionally powerful driver for advocating conservation of habitats. But if local stakeholders finds the idea of saving mustangs not so appealing, maybe the authorization can a) find another proxy wildlife to achieve the same goal, or b) persuade local people to accept mustangs as a healthy symbol and a worthy backup gene bank that can be used to strengthen their own livestock. Option (b) seems to be an easier way, and the NG article no doubt does it good.

Now I can't help thinking, if we Chinese linked Chinese sturgeon *Acipenser sinensis* with something more meaningful rather than saying in our dictionaries that it is edible, perhaps Yangtze River as an important habitat would be better protected.

中美能源合作的新契机

英国《卫报》[报道](http://www.guardian.co.uk/environment/2009/feb/11/network-us-china-climate-change)，中美两国50多名专家日前起草了一份报告，旨在为奥巴马政府提供一份与中国在能源和减排技术领域进行合作的路线图。这份报告是由亚洲协会美中关系中心和 Pew 全球气候变化中心发布的，全文可以在 Pew 中心的网站[下载](http://www.pewclimate.org/US-China)。

报告指出了两国可以开展合作的五大方向，包括发展低排放煤炭能源技术，提高能源效率和改善节能措施，开发先进电网技术，推广可再生能源，以及投入资金发展低碳技术。报告指出，虽然目前的经济形势对大规模的环境投资造成了压力，但高额的基础设施建设投资和经济刺激方案也能带来改变现有能源体系的难得契机，同时造就大量的[“绿领”](http://www.guardian.co.uk/environment/2009/feb/12/green-collar-jobs-environment)工作岗位，可谓一举多得。报告认为，中国和美国作为世界上最大的发展中国家和发达国家，以及最大的能源消费国和温室气体排放国，如果能够在气候变化问题上展开合作，将对哥本哈根会议之后的气候问题格局乃至更广泛意义上的世界格局都产生积极的影响。

这一合作能否实现，取决于双方是否愿意参与，以及投入到什么程度。从美国的角度推测，对中国进行适当的技术出口将有利于形成积极面对气候问题的国际形象，在未来的气候谈判中获得有利地位。但在有限的资金和高昂的外债负担条件下，在经济不景气的时期美国能够投入多少资金到低碳项目和风险巨大的新技术验证项目的建设当中还是未知数。而中国能够通过合作获得的技术看起来相当有吸引力，但美国对于知识产权的顾虑也可能对技术的转移产生不利影响。更重要的是，中国是否能将发展可持续能源与发展欠发达地区的目标统一起来。

从政治经济的角度说，合作如果能够实现，将是中国在未来国际上进一步提升影响力的契机，同时可能对西方的经济复苏产生积极影响，甚至使[世界经济重心向东方迁移](http://davidharvey.org/2009/02/why-the-us-stimulus-package-is-bound-to-fail/)。

Carbon Trade 的问题

最近碳排放权交易方案在欧盟又成为了热门话题，部分原因是即将于年底在哥本哈根召开的[气候峰会](http://en.cop15.dk/)，更重要的原因是越来越多的人对这个方案的效果提出了质疑。就连一向支持碳排放权交易的能源公司发言人也指责碳交易有可能[成为新的次级投资](http://www.guardian.co.uk/environment/2009/jan/30/eu-carbon-trading-scheme)，更有人提出应该将碳交易制度[全盘推翻](http://www.guardian.co.uk/commentisfree/2009/feb/01/emissionstrading-carbonoffsetprojects)。碳交易制度面临的问题，反映了将二氧化碳作为金融产品带入经济活动的过程中的困难。由于各种单位产值不同的经济活动都会产生数量不等的碳排放，为了建立一个实际可运行的统一碳市场，只有人为地规定配额和单位碳排放的价值。这个定价已经多次被指责为脱离了市场经济的实际，因此欧盟在去年底降低了配额总量，以确保碳排放的价值不会降低到损害减排积极性的水平。但时隔不久，碳交易价格就[再度崩溃](http://www.guardian.co.uk/environment/2009/feb/07/cost-carbon-credits-falls)。当前的经济形势决定了碳排放的总量在没有有意干预的情况下也会降低，而碳配额没有对此及时作出反应，使得大部分碳交易的参与者都有排放权可供出售，造成市场崩盘。在一般的市场活动中不待见计划经济的欧盟，在碳交易市场的设计上好像倒不自觉地采用了计划经济的手段，试图制定一个统一的碳排放帽子（cap）来处理纷繁复杂的经济活动，结果吃力不讨好。

如果说一个不合适的碳配额拖延了减排进程的话，那么欧盟[排放交易制度](http://ec.europa.eu/environment/climat/emission.htm)（ETS）规定的可以用发展低碳能源和生产技术替代实际减排的做法可能实际上会导致企业离减排目标越来越远。通过允许世界各国用京都会议规定的清洁发展机制（Clean Development Mechanism, CDM）节能项目来换取碳排放配额，ETS 实际上允许企业一边建设利用可持续能源的手段，一方面用换来的碳配额继续发展高排放的工业和项目。从理论上说，ETS 是把不该内部化的企业用于减排的投资内部化了，这部分投资的收益应该体现在减少的碳排放费用，但现在可以反而用来换取更多的配额和金钱。欧盟在减排问题上想当世界领头羊的愿望，这次让他们制定了一个自挖墙脚的政策。

ETS 制度关于换取排放配额的规定可以改变，但是计划经济式的总配额要改进很困难。比较可行的也许是碳税制度，不过在目前的经济环境下，碳税带来的消费减少的副作用，又跟各国政府刺激消费的手段背道而驰。当然，刺激消费还有别的办法，推动减排的办法却不多，而且科学界早已指出，[信贷危机不应阻碍对气候变化采取行动](http://www.newscientist.com/blogs/shortsharpscience/2009/02/fred-pearce-senior-environment.html)。

生态拓扑学：新瓶旧酒

Image via Wikipedia

1999年美国的 NSF 在[一篇论文](http://www.ingentaconnect.com/content/aibs/bio/2001/00000051/00000001/art00005)中提出生态拓扑学应该成为未来生态学研究的四大前沿之一（另外三个是地区物种池产生的复杂社群发展，生态记忆在生态过程中的作用，以及复杂系统的涌现特性）。这篇论文在[这里](http://www.planta.cn/forum/viewtopic.php?t=7256)有中文的简介。

最近在 Ecological Complexity 上发表的一篇论文则对生态拓扑学这个概念的应用进行了[综述](http://dx.doi.org/10.1016/j.ecocom.2008.11.001)。作者指出，生态拓扑学虽然被作为研究的前沿，但其理论和方法事实上至少已经被生态学家们应用了超过半个世纪。拓扑学的两大奠基人物 Euler 和 Poincaré 分别确立了这门学科的两大分支，Euler 提出了图论和网络拓扑学，而 Poincaré 则提出了用几何方法抽象动态系统的概念。这两种基本的拓扑学方法在生态学研究中都得到了应用。网络拓扑学促进了食物网等概念的研究，以及多种系统模型的建立；Poincaré 的流型概念则推动了 bifurcation 和跨比例作用等概念的出现和非线性生态模型的发展。

在今天，这些研究领域仍然是生态学中的热门问题。综述的作者指出，生态学中的许多数学方法本质上都代表了拓扑学的思想，深入对拓扑学的研究，有助于更好地评估对生态过程的跨比例理解，更好地定义系统的因果性边界，建立连接不同尺度的形式结构，通过系统结构研究物种互动，以及帮助人们理解那些不易直接观察的“高阶现象”。Panarchy 等研究系统不连续性的方法也与拓扑学概念有直接的联系。综述的作者认为，以更为规范的形式讨论拓扑学在生态学中的作用，将有助于更深入和广泛地理解复杂生态系统。将拓扑学与空间统计、GIS 等其它手段结合应用将帮助我们更好地理解自然。

当然，作者也认为将自身就是两个分开的部分的拓扑学显式地引入生态学研究中，会有一些概念定义和与现有方法整合的困难。也许我们不需要作为生态学分支的拓扑学，但引入拓扑学的方法是一个可能的研究方向。

Prager, S., & Reiners, W. (2009). Historical and emerging practices in ecological topology Ecological Complexity, 6 (2), 160-171 DOI: 10.1016/j.ecocom.2008.11.001

Yet another use of ice record

Today's ScienceDaily [reported](http://www.sciencedaily.com/releases/2008/12/081231131813.htm) a new possibility of ice core sample analysis, this time using bacteria frozen in the ice.

It was found that in ice core sample collected from Mountain Geladaindong, the abundance of bacteria is in accordance with $$\delta ^{18}\text{O}$$, which can serve as an indicator of temperature. It is already known that higher $$\delta ^{18}\text{O}$$ level implies higher temperature, now it seems bacteria abundance also increases with $$\delta ^{18}\text{O}$$, therefore it is possible to use bacteria numbers as an indicator of historical temperature change.

However, $$\delta ^{18}\text{O}$$ can also serve as an indicator of precipitation, with higher level in low-precipitation years. It has also been noted that in the ice core higher bacteria level concurs with higher amount of dust. So here's my speculation: it may well be that in dry years the dust activity is more pronounced, leading to more dust and bacteria precipitate on the glacier. In that case, bacteria itself is not a useful indicator of either temperature nor precipitation.

It is also interesting to note that the lowest bacteria level was found in 1938 and the highest in 1997. According to [Desert Research Institute](http://www.wrcc.dri.edu/enso/ensodef.html), 1938 was a strong La Niña year, while 1997 was a strong El Niño year. So there is possibility that the effect of El Niño/La Niña may have so strong signals that the actual trend due to climate change is harder to observe. Moreover, if the bacteria abundance is proved more correlated to El Niño/La Niña, it suggests the increased possibility that bacteria level is linked with precipitation rather than temperature, as [earlier research](http://ecosystems.wcp.muohio.edu/studentresearch/climatechange03/elnino/Ice%20core%20records.pdf) argued that precipitation is more correlated to El Niño than $$\delta ^{18}\text{O}$$ does.

On the other hand, if this method is proved feasible, it would mean that scientists have get hold of another relatively cheap way of deriving historical climate data, and do not have to deal with expensive isotope analysis. Similar method may also be used in lake sediment or peat analysis. But to validate this method, "we need more data".

《Collapse》：为明天而改变

对于一个从[《枪炮、病菌与钢铁》](http://www.douban.com/subject/1054760/)之后第二次接触 Jared Diamond 作品的人来说，对这本书的论点持一定的怀疑态度是有必要的。这本书的写作风格与《枪炮》如出一辙，而且也一样成为了叫好又叫座的畅销书。这不免让人怀疑Diamond 与 Leslie Brown 或 Lomberg 一样都是以研究为名拼凑所谓证据，炮制一本又一本畅销书的主儿。对我来说，这种怀疑在阅读的过程中虽然没有完全减退，但 Diamond 继《枪炮》之后又一次以他旁征博引的写作风格和流畅大气的文字打动了我，使得我相信他不太可能为了说服读者而有意扭曲引用的证据，更不可能仅仅为了写一本畅销书而抛出一个看似惊世骇俗的论点再勉为其难地用片面的论证来“证明”。Diamond 写书的意图，据他自己说，是在惊讶于玛雅和复活节岛文明的神奇之余，想到了为什么这些古老的社会最后不免于崩溃的命运。写作这本书，也是为了让读者能够以史为鉴。从这个目的出发， Diamond 再次使用了传统史学家的写作方法，试图通过对历史案例的分析，归纳出以往社会走上崩溃或繁荣道路背后的文化、体制、政治和经济原因，并讨论现代社会面对的不同挑战及如何避免崩溃。和《枪炮》一样，这本书的大部份章节分别讨论了不同的案例，每个章节中案例的叙述与分析既有机地紧密结合，又泾渭分明；描述的部分文笔流畅生动令人不忍释卷，论证的部分即使不是无懈可击，也做到了详尽周密，对于这个领域的研究没有超过 Diamond 本人的人，是很难辩驳的。这本书不是严肃的学术著作，但作为科普读物，在有力地传达了大量信息的同时又没有丧失可读性，可谓难能可贵。

全书的中心问题，是人类社会如何及为什么选择了通向最终崩溃或长期繁荣的道路。这个问题的变体，是为什么某些社会即使明知自己选择的道路是不可持续的，还是头也不回地沿着这条道路走下去？Diamond 在书中对这两个问题都从他的角度进行了充分的讨论。他将古往今来社会崩溃的原因归纳为五大因素：

1. 环境的破坏；
2. 气候变化；
3. 来自毗邻社会的敌意和威胁；
4. 缺少或失去友好邻邦的支持；
5. 社会对面临问题的反应。

其中第二点，对于古代社会而言并非人类造成的气候变化，所以人类并没有多少选择权，而一个社会对于其邻邦的选择自由也有限，因此纵观全书，不难看出 Diamond 还是给了环境问题和社会的适应这两个议题最多的关注。在环境问题的讨论中，作者几乎每次都必会谈到人口问题。在诸如复活节岛和玛雅这样的社会，不受限制的人口增长与气候变化的相互作用造成了环境与发展的[尺蠖效应](http://www.snakehsu.info/wordpress/?p=458)：在气候适宜的时期，社会的发展以环境的承载能力为代价；而气候变得恶劣时，社会的损失又是以社会资本（经济和机构）的破坏来弥补。如此反复的拉锯是这些社会走向崩溃的一个重要因素。那么这些社会为什么没有在第一次面对恶劣环境时就改变它们的发展模式？Diamond 归纳了如下几点原因：首先是社会和环境资本的变化极度缓慢，有时超出了人类的认知可以感受的范围；其次即使社会感受到了负面因素的影响，占统治地位的精英（或特权）阶层可能并未直接受到影响，因此也缺乏带领社会走出困境的动机；最后，社会可能极度良好地适应了某种环境或文化认同，以至于在改变到来时没有人愿意放弃已经不合时宜的某些核心价值观。

如果说展示一个社会面对的问题，并呼吁人们采取行动，并不是什么有新意的题材，那么或许可以说《Collapse》将这个题材以一种更具鼓动性，更令人不安的方式上升到了一个新的高度。Toynbee 的[《历史研究》](http://www.douban.com/subject/1052983/)提出了挑战与应战这个范式，用它来解释过社会的崩溃，Diamond 则在继承 Toynbee 的衣钵之余，将这个范式深化，提出了为什么有些社会直接放弃了应战这个问题。而这个巨大的问号，在被 Diamond 联系到当今美国和世界的现实之时，就带来了值得更深入思考的问题：高度成功的工业文明是否也削弱了社会适应变化的能力？当今的精英领导阶层是否有足够的魄力带领社会放弃某些威胁社会存续的核心价值观来保证社会的生存？诚如 resilience 理论（[http://www.resalliance.org/](http://www.resalliance.org/)）所注意到的，在一个系统度过迅猛发展的 r 阶段后，随之而来的 K 阶段保证了前一阶段的物质成果在不断的变化中被保留下来，但代价是系统在变化中维持其关键功能的能力（resilience）不断被削弱，系统也越来越难以适应新的变化。在随后的 $$\Omega$$ 阶段，系统将崩溃，释放 resilience，供下一阶段的重组和发展使用。

世界是否正处于这个 K 阶段？Diamond 并未明确断言。但他在《Collapse》的最后一章中指出，许多社会的崩溃都是发生在其鼎盛时期后一二十年，因此他呼吁在今天的发展中应当更加注重长期的规划，并重新考虑被社会作为核心价值的一些理念的重要性。理想化地说，我以为最后一章可以作为领导人必看的一份 Executive Summary，Diamond 在其中列举了威胁社会生存的十二大问题，也有力地反驳了“照常营业”派决策者和人类（技术）中心主义者在讨论环境、资源问题时经常使用的一些观点。特别重要的是，他指出在当代也有社会由于与古代社会相同的原因，正在发生崩溃或处于崩溃边缘。与古代相比，现代社会大大增加的人口与全球化，使得全球性的崩溃成为可能。正如复活节岛是太平洋中的一个孤岛一样，地球也是太阳系中的孤岛，一旦它发生崩溃，我们无路可逃。

遗憾的是，并不是每一个领导人都会读这本书，在读过后能把长期规划的理念进行实践的可能更少。而且 Diamond 作为正面例子的一些社会，从其全球生态足迹和不可再生资源的消耗来看，也未必就是可持续性的样本。但如果这本书的众多非精英读者们能够思考一下他们的核心价值观，并愿意为社会的存续做一些必要的改变，也许真的能为社会的发展带来新的面貌。因此，我向每一个人力荐此书。

维京人在格陵兰的覆灭与两种适应

[caption id="" align="alignnone" width="130" caption="Book cover via Amazon"][/caption]

昨天爱丁堡大学的 Andrew Dugmore 教授到本校来做了一个讲座，主题是讨论格陵兰岛的维京人的 resilience 和 adaptation。因为和我做的课题有关，而且这几天我在看 Jared Diamond 的 Collapse 这本书，正好也看到关于格陵兰岛维京人的章节，所以对这个讲座很感兴趣。而且这好像还是我在英国第一次看到做 resilience 这方面研究的教授，以前看文献的时候总以为这个东西只有美国和澳大利亚的一小撮人在研究，现在知道离自己相对较近的地方也有人做这个还是挺高兴的。

Andrew 一上来还是从 panarchy 的概念入手，着重介绍了其中的跨尺度（inter-scale）作用，包括大尺度的慢过程对小尺度的快过程的影响（remember），以及小尺度过程的反作用（revolt），事实上维京人与格陵兰岛环境的互动也可以用这两种作用概括。Andrew 与 Jared Diamond 似乎有过接触，他也提到了 Collapse 这本书里对维京人的描述。Andrew 和 Jared 都注意到，一个不可忽视的事实是维京人的环境管理与我们想象的不同，虽然他们一开始对冰岛和格陵兰岛的树木都进行了破坏性的砍伐，但他们都很快意识到树木对草地和他们赖以生存的畜牧业的重要性，并停止了砍伐，并通过调整畜群结构建立起了基本可持续的畜牧业（冰岛可以认为是半可持续地发展了上千年，目前是欧洲生活水平最高的国家之一），但为什么格陵兰岛的维京人没有取得像在冰岛那样的成功，并最终消失了？

一个重要的原因是格陵兰岛的气候比冰岛的更寒冷，但 Andrew 指出，事实上维京人一直适应得很好，建立了完善的社区，并且许多牧场一直保持了良好的状态。他们几乎做对了每一件事情，但无法预见到公元1400年左右的小冰期的出现。气候和植被模型显示在小冰期植被的生长季变短，使得秋季可用的牧场面积局限于较低海拔的区域，而已有的牲畜数量在有限的草场上造成了破坏，而从破坏发生到变得可见再到采取措施都需要相当长的时间，维京人一度适应得非常好的畜牧和狩猎生产方式没有能适应这个突然的变化，其发达的畜群不能在短时间内减小规模，因为适应于畜牧的维京人找不到替代的生产方式，结果导致了其社会在十三世纪初的崩溃。

[caption id="" align="alignright" width="240" caption="The "East Settlement" of Vikings in Greenland"][/caption]

这个理论的警示意义是明显的。和维京人一样，今天的我们也没有对于未来可能发生的突然变化的知识。当变化发生时，我们对已有条件的极度发达的适应可能反而让我们在变化面前无所适从。一个简单的例子是粮食生产，当粮食剩余实际上依赖于大量的能源和化工产品投入的时候，如果生产必需的资料突然出现极度的短缺或者失效，就可能造成严重的影响。而且这种突然的变化出现的可能性，并不因为我们今天的社会比维京人更发达而减小。

在维京人覆灭的同时，因纽特人在格陵兰岛上取得了成功，以至于十六世纪重返格陵兰的欧洲探险者以为因纽特人是格陵兰岛唯一的原住民。Andrew 对于因纽特人的成功的解释是，不同于定居的，农业文化的维京人，因纽特人适应了游猎式的生活方式，他们的流动性（mobility）使得他们能够接触更广阔多样的环境，从而在变化面前有更强的适应能力。活动范围大，意味着因纽特人有更多的选择，这也使得他们的社会更加 resilient。

从这里我想到，当我们讨论社会和人群的适应时，我们说的 adaptation 有两层含义，其一是对现有环境的适应，这种适应是小尺度过程对大尺度过程的 remember 作用的反应，用 adaptive cycle 来解释的话，对应其 r 阶段和 K 阶段；其二是对变化本身的适应，即变化发生时能否及时调整为另一种模式，同时保持系统的关键功能的存在，对应 adaptive cycle 的 $$\Omega$$ 和 $$\alpha$$ 阶段。理想化地说，第一种适应不应当以第二种适应为代价，在改善对某种特定环境的适应的同时，我们也应当维持适应另一种或多种完全不同的条件的可能性，或者至少延缓这种可能性的消失。

不能否认的是我们仍然像维京人一样没有意识到这个问题，我们的生活方式的进步往往导致了适应变化的可能性的丧失，这体现在物种的消失和对个别资源的过度依赖上。至于对第二种适应非常必要的 mobility，在人口日益增长的今天似乎也越来越难保证。虽然在全球化的今天个人可以越来越容易地迁移，但人类还是一种不喜欢陌生环境的动物，结果全球化只带来了趋同的城市和中国城韩国街意大利区这样的聚落的存在，都不利于人类适应变化的环境。维护文化的多样性，同时鼓励与外来人群的交流，以及维护自然环境的多样性，对于人类的第二种适应，我认为将同等重要。

听完 Andrew 的讲座后我又赶场去听了 Tindall Centre 的 Mike Hulme 的讲座，关于“Why we don't agree on climate change”。与他人不同的是他不讨论气候变化的原因或者解决方法或者争议，而是探询为什么存在争议。他指出这是一个文化和思维方式的问题，四种思维范式─怀旧、恐惧、改变自然的骄傲和对社会正义的诉求导致了目前关于气候变化的复杂叙事的出现。也许“我不同意”确实是人类的天性，这也许也能解释为什么人类在突然的变化面前总是要一段时间才能采取行动吧……但这正是让我们成为人类的重要的特质，我们也许不应该为了更好的适应而抛弃它。

Prioritising conservation objectives

An article in press in a recent issue of TREE proposed that triage approach should be explicitly employed in decision-making about the allocation of limited resources in conservation efforts.

Prioritising conservation objectives, in my opinion, is really not new.  All decision makers have to balance limited funding and other resources among a few (sometimes contradicting) conservation goals.  However, the author of the article argues, triage has been regarded as defeatism thinking and may lead to abandoning conservation efforts that is meaningful and has a high probability of success.  Due to the unpopular image of triage, decision makers often have to avoid mentioning triage in conservation planning explicitly.  Doing so leads to irrational policies and decisions hijacked by evaluations other than those that based on ecological and economical principles.

The author proposes that the triage process should be mentioned explicitly in planning and follow certain rules in consideration so as to achieve rational triage and optimised outcome.  The four principles should be considered are: values, biodiversity benefit, probability of success, and cost.  The latter two are not difficult to understand.  However the evaluation of values and biodiversity benefit may involve some complexities and very lively debate.

The objective function that the author proposed is the product of the first three factors divided by cost.  The resources are allocated to project that yields highest outcome in this equation.  Such an approach is straightforward.  Nevertheless, the questions that how to estimate the value of a particular species or ecosystem and how they affect local and global biodiversity have no definitive answers.  Theories such as the driver-passenger analogy may help but cannot address all the complexities in ecosystems.  Species-by-species conservation may overlook species and ecological functions that deemed not important or economically worthy of conserving.  Even the loss of a few seeming unimportant species with overlapping ecological functions in the long run may cause sudden collapse of the system by decreasing system resilience.

Thus it is necessary to examine the value of species and their biodiversity benefits from multiple perspectives.  The real benefit of making triage decision-making explicit, in my opinion, is to allow multiple stakeholder groups as well as researchers with different conservation goals to evaluate the conservation options and achieve more informed decisions.  The positive role triage approach plays therefore depends on how open and constructive the decision-making process is.

科学地表达科学

这期的 Science 杂志在 Policy Forum 栏目刊载了一篇文章，报道了在 MIT 进行的一次实验：

[caption id="" align="alignleft" width="235" caption="测试中使用的材料。上半部分取自 IPCC 的决策者报告（SPM），下半部分是测试题目。来源：J. D. Sterman. Economics: Risk communication on climate: Mental models and mass balance. Science, 322(5901):532–533, 2008. "][/caption]

实验对象都是 MIT 的高材生，给他们的材料上给出了 IPCC 一份给决策者看的报告[1. 这并不是去年出版的最新报告，不过新报告也有此文中讨论的同样问题。]中的一个大气二氧化碳含量趋于稳定的图景。测试要求实验对象们首先根据目前的二氧化碳自然去除水平（图中的黑点）估计未来的自然去除水平，然后画出实现 IPCC 二氧化碳稳定图景所需的未来二氧化碳排放量的走势。

在往下看之前，你不妨也做一下这道题。你画的图是什么样的？

MIT 的学生们的测试结果让人失望。84%的答案都忽视了这个简单的问题：就像要让澡盆里的水面保持稳定，进水量和出水量必须一致一样，二氧化碳含量的稳定要求排放量与自然去除量相等。被测试者典型的答案是二氧化碳的排放量趋于稳定，但仍然是去除量的2倍左右。这种情况下，二氧化碳的含量只会越来越高。

文章的作者据此提出，在这个问题当中，人们固有的思维模式影响了他们的判断。人们倾向于认为只要排放量不再增大，总量也不会再增大。而且这次犯这种错误的学生中有约3/5还是理工科的学生，大部分都已经有硕士及以上的学位。

而这个问题，只要 IPCC 的报告中能够用澡盆或者其它的物质平衡现象打个比方，就完全可以避免。

我自己则怀疑造成这种现象的至少一部分原因是题目文字的表述。题目原文是“given the scenario above”，对于一直在中文语境中接受考试的我来说，其提示作用并不是那么强烈，我的理解是画出未来可能的排放量。在没有其它信息的情况下，我自然很可能认为未来的排放量会维持现状，因此得出那样的答案也就不奇怪了。如果改成“in order to achieve the scenario above”，做对答案的人会多一点吗？

所以我用中文转述这个问题的时候有意改变了措辞。你做对了吗？

[caption id="" align="alignleft" width="411" caption="测试中大部分对象给出的答案。粉红线为学生的答案，金色线为实现 IPCC 图景需要的排放量轨迹。来源：J. D. Sterman. Economics: Risk communication on climate: Mental models and mass balance. Science, 322(5901):532–533, 2008. "][/caption]

不管 MIT 的高材生们因为什么原因被这道题阴了，它确实暴露出将科研成果传达给公众和决策者时的一个问题。IPCC 的报告和其它报道类似问题的学术刊物中，使用的表达手段还是科学家之间讨论这些问题所用的语言。连 MIT 的理工科学生都不能完全理解的，要让决策者和老百姓理解就更困难了。

在无法理解科学家所说的那些“事实”“预测”的情况下，大部分人选择照常营业等待科学家解决问题，或者干脆否认气候问题的存在，也就是完全可以理解的反应了。

于是文章的原作者提出不应该继续让决策过程继续基于错误的思想模式，要做到这一点，科学家和科技通信作者需要更好地了解普通人的心理和认知模式，用心理学和社会学的科学方法进行思想的交流，同时不再用大量专业的科学数据来进行灌输和恐吓。关于气候变化的思想工作，科学证据是充分的，真正的困难在于如何用正确的方式传播，同时保证其对民众的心理起到正确的作用。对于气候变化这样一个复杂的综合性问题，沟通科学家和其他人的想法还真是个难题。

图片来源：J. D. Sterman. Economics: Risk communication on climate: Mental models and mass balance. Science, 322(5901):532–533, 2008.

三聚氰胺和它的表兄弟们

声明：本人大学有机化学几乎不及格，因此文中所述仅代表本人想法，不建议以本文作为任何讨论的论据。本文对食品的选购无指导意义。引用和转载本文必须包括原 blog 链接和本声明。

现在写奶粉事件不知道是不是有点后知后觉。不过没有刻意去搜集信息的我也没有搞清楚为什么三聚氰胺会导致结石，美国 FDA 在2007年进行的风险评估（有兴趣的同学可以到译言翻译此文）表明三聚氰胺的对老鼠的半致死剂量（LD₅₀）是3161毫克/公斤体重，毒理学里这算是个很大的量，所以报告在 executive summary 里说食用含三聚氰胺的饲料喂养的动物制品并不对人体健康产生威胁。但同时，报告也注意到了对狗的喂养实验中被投喂1200毫克/千克体重/天并持续一年的狗出现了结晶尿现象（crystalluria，求正确译名），对食用了含三聚氰胺饲料而死亡的宠物的尸检则显示它们死于急性或亚慢性肾衰竭。这份报告也注意到了结石现象，指出13周的鼠类实验中不产生不良作用的最高限是63毫克/千克体重/天并将其作为对人体风险评估的指导标准。

三鹿奶粉的检测结果是2563毫克/千克，按照英国的标准，婴儿每天每公斤体重摄入的婴儿配方奶粉量应为2.5-2.7盎司，合0.070到0.076千克奶粉，也就是说三鹿奶粉的受害者每天摄入的三聚氰胺至少是179毫克/千克体重。反过来算，800毫克/千克以下含量的三聚氰胺也许还不至于在一两年内造成明显的健康问题，从这个角度看，那个奶粉吵架的段子还真有些道理，也说明三鹿曝光以后对奶粉行业的全面检验是正确的和必要的，不然这个问题可能还会被埋藏很久。

虽然在零容忍的前提下，检出三聚氰胺就已经让乳制品行业被扣分不少，但是我还是想指出仅仅检验三聚氰胺一项并不是最可靠的鉴定方法。今天的 Science Blog 里有一篇文章谈到了中国的乳制品问题，并链接了去年华盛顿邮报对宠物中毒事件发表的一篇科普文章，这篇文章指出，虽然猫狗饲料中的三聚氰胺实际上远未达到致死或产生结石的剂量，但饲料中含有的另一种毒性不及三聚氰胺的化合物氰尿酸（cyanuric acid）成了帮凶。三聚氰胺和氰尿酸两种化合物的分子结构类似（见图，取自 FDA 风险评估报告），而且据报道在猫的尿液中很容易依靠氢键作用形成三个三聚氰胺和三个氰尿酸分子构成的不溶六聚体从而造成结石，即使三聚氰胺本身的含量并不超过猫的排泄能力。据报道，32毫克/千克体重单次剂量的这种聚合物就可以在猫身上造成急性肾衰竭。所幸这种聚合物在酸性环境下很容易分解。但对于胃肠功能不佳或者不完善的人它可能造成大麻烦。牛奶本身的 pH 在6.5-6.7左右，也并不是最适合分解这种聚合物的酸度。

三聚氰胺

氰尿酸

大部分简体中文媒体似乎只注意到了三聚氰胺而没有注意到它的类似物，跟去年的华盛顿邮报相比，我们也许都有点后知后觉。氰尿酸作为副产品容易在三聚氰胺加工制备过程中被混入，去年美国在宠物饲料中也有检出，而且其氯代物三氯异氰尿酸在乳制品行业中常用作消毒剂，水解后也可产生氰尿酸。由此推出即使乳制品中没有三聚氰胺，也可能混有氰尿酸。所以，要正确评估食品和饲料中三聚氰胺的危害，还应该把氰尿酸也纳入考虑当中。我不太清楚质检总局对奶粉抽检时采用的分析方法，如果使用的是蛋白质氮含量与总氮含量的差值法，则可能给出的结果已经包括了氰尿酸，但我们也关心这二者的比例。总之我们对于三聚氰胺以外的其它有机物杂质的危害应该有一定认识。反过来说，如果能通过色谱等手段证明某些乳制品里检验出的少量“三聚氰胺”只是氰尿酸的话，则不必太过担心，因为可能只是在生产过程中从器具和生产线上无意混入，而且它的（毒理学意义上而非通俗意义上的）毒性较三聚氰胺要低得多。