[http://www.sciencemag.org/cgi/content/full/318/5855/1368](http://www.sciencemag.org/cgi/content/full/318/5855/1368)
With no doubt, climate change is one of the biggest challenge the mankind faces in the new century. Perhaps this explains why there are quite some strange proposal to battle increasing green house gases. For example, there are some researchers proposed to [increase aerosol in the atmosphere to block solar radiation](http://www.guardian.co.uk/environment/2007/jan/27/usnews.frontpagenews) as aerosol is observed to lead to [temperature decrease in some cities in China](http://www.terradaily.com/reports/Haze_Dynasty.html) and [may cancel out some effects of global warming](http://www.sciencemag.org/cgi/content/summary/283/5406/1273). This somehow reminds me of ``Operation Dark Storm'' in [Animatrix](http://en.wikipedia.org/wiki/The_Second_Renaissance#Part_II). But of course such a proposal will get almost nil support from any reasonable person.
Now here is the new idea: pump iron into the sea. As the sea has a sufficient level of nutrient already and iron is the limiting factor, this will lead to virtually an explosion of algae which will need considerable amount of carbon to grow and will rapidly sink into the sea, which may be a way of sequestrating carbon. If practical, this will be a cheap solution to reduce carbon in the atmosphere. However, from the article in science you can read a lot of suspicions with various reasons: altered ecosystem, the efficiency of the sinking process, and the methane and nitrous oxide emitted in the process.
As there are too many uncertainties, further experiments are desirable. This is supported by some companies which hope to earn some credits in the carbon trading system. Personally I hope the experiment a success. However I also have my own doubt: will the sea saturate? There are reports saying that the capability of ocean carbon sinks are decreasing, and in a recent article, Canadell et al. states:
[C]arbon emissions have grown faster than CO2 sinks on
the land and oceans. Because the land and oceans are
both mosaics of regions that are gaining and regions that
are losing carbon, this trend could result from any or all
of three scenarios: sink regions could have weakened,
either absolutely or relative to growing emissions; source
regions could have intensified; or sink regions could have
transitioned to sources. (Canadell et al. 2007)
And Le Quere et al. (2007) have reported that the Southern Ocean is losing ability to absorb carbon dioxide and becoming a source instead.
I know very little about the metabolism of algae and the biochemical process in the ocean, but I think the researchers proposing the experiment should also consider carbon that cannot make it to a depth below 500 metres. Will they enter the ocean and accelerate the saturation of carbon? If so, in what condition?
My other complain is that this proposal, even if a success, should not be relied upon as a solution to climate problem. It should function more as a means to slow the process of climate change and earn some time for mankind to ultimately solve the carbon balance. I am worried that successful carbon sequestration will only lead to more emission. A mature carbon trading system may help, but a global monitoring and enforcement system urging everyone's adaptation to cleaner energy and smaller carbon footprint is the solution.
1. J. G. Canadell et al., [“Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks,”](http://www.pnas.org/cgi/reprint/0702737104v1.pdf) Proceedings of the National Academy of Sciences (2007).
2. C. Le Quere et al., “Saturation of the Southern Ocean CO2 Sink Due to Recent Climate Change,” Science 316, no. 5832 (June 22, 2007), [http://www.sciencemag.org/cgi/content/abstract/316/5832/1735](http://www.sciencemag.org/cgi/content/abstract/316/5832/1735).
2007年11月30日星期五
2007年11月26日星期一
A better evaluation?
My research needs a conceptual model. At present, I think it would be desirable to have a social dimension aside of the ecological one. Therefore, in the conceptual model, I need not only links denoting the flow of nutrient and energy, but also those representing flow of ecosystem services, which can be considered as the interface between the "human" and the "nature" parts in the system.
But "ecosystem service" would be too abstract to use even in a conceptual model. A concrete, and more desirable if universal surrogate of [these services](http://www.greenfacts.org/glossary/def/ecosystem-services.htm) is needed. I am very reluctant to use monetary measures as there are many values that cannot be underestimated using such an approach.
A search at Google Scholar gives about [200 results](http://scholar.google.com/scholar?num=50&hl=en&lr=&newwindow=1&q=%22ecosystem+service%22+surrogate&btnG=Search) using keywords "ecosystem services" and "surrogate". After a browse I cannot say that I find much enlightenment, although [this one](http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V5X-4CC7V6J-D&_user=10&_coverDate=12%2F31%2F2004&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=52b27906458558832f14c738d40e8a95) is interesting. Non-linearity and changes should be considered when choosing the sorrogate. But it will not do if too many factors are considered, right?
Biodiversity is another often (ab-)used surrogate. But it is surely not adequate for the area I am studying, as the productivity there is so limited that it can only support a relatively simple system. The only way to achieve ``diversity'' is eutrophication, not like an option.
Or as an alternative, the energy flow combined with monetary evaluation can be used as the measure of ecosystem service?
But "ecosystem service" would be too abstract to use even in a conceptual model. A concrete, and more desirable if universal surrogate of [these services](http://www.greenfacts.org/glossary/def/ecosystem-services.htm) is needed. I am very reluctant to use monetary measures as there are many values that cannot be underestimated using such an approach.
A search at Google Scholar gives about [200 results](http://scholar.google.com/scholar?num=50&hl=en&lr=&newwindow=1&q=%22ecosystem+service%22+surrogate&btnG=Search) using keywords "ecosystem services" and "surrogate". After a browse I cannot say that I find much enlightenment, although [this one](http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V5X-4CC7V6J-D&_user=10&_coverDate=12%2F31%2F2004&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=52b27906458558832f14c738d40e8a95) is interesting. Non-linearity and changes should be considered when choosing the sorrogate. But it will not do if too many factors are considered, right?
Biodiversity is another often (ab-)used surrogate. But it is surely not adequate for the area I am studying, as the productivity there is so limited that it can only support a relatively simple system. The only way to achieve ``diversity'' is eutrophication, not like an option.
Or as an alternative, the energy flow combined with monetary evaluation can be used as the measure of ecosystem service?
2007年11月22日星期四
2007年11月16日星期五
理性的幻想家
今天读完了 Ursula K. Le Guin 奶奶的 [The Language of the Night](http://www.anobii.com/books/Language_of_the_Night/9780704342026/01a65fb3e4b0a2a830/)。200多页的小书，从10月11日到现在，总算断断续续地读完了，好在这本集子里的文章都不算太长，每天读一篇，或许不能获得编者 Susan Wood 所希望读者获得的整体印象，但对于 Le Guin 对于科幻文学和艺术的态度，倒是可以有个大致的了解。
今天的科幻文学，比这本书里大部分文章写成的年代里的科幻小说，恐怕不能说有长足的进步，反倒显露出日渐式微的趋势。而在70年代，Le Guin 就观察到了这种现象，并将其归因于社会对快餐文化的追捧和功用主义对幻想的抵触，这个主题是这本书第一、第二部分的重点。除了社会的不认可，Le Guin 也指出在社会不将科幻作为主流文学看待的情况下，科幻作家们妄自菲薄，在写作时的态度有所欠缺，也是造成部分科幻小说文学性不强的原因，这是第三部分的主题。
Le Guin 在第四部分接着提出了她认为的好的科幻小说应具有的性质：文学性，科学上的可信性，以及艺术性。她在这部分也提出了她对新手开始科幻写作的观点。最后一部分，她鼓励科幻作家将自己的作品作为艺术来对待，不要用“仅仅是娱乐”来自嘲，也不要受到“市场审查”（Market Censorship）的影响，为迎合大众的口味炮制模板化、快餐式的小说。
书中贯穿始终的一个主题还包括女性主义的思想——虽然 Le Guin 本人在80年代的新版序言中也说这是70年代的女性主义——更多地主张男女平权而非提出一个女性视角，还有就是对幻想文学的艺术价值的肯定和对批评家们指责幻想是“escapism”的反驳。其实，虽然整本集子谈的都是科幻和奇幻，Le Guin 的主张——将作品看作艺术——对于其他创作，也是具有积极意义的提法。再推广一下，甚至也可以说工作和研究在一定程度上也需要这种态度。
Le Guin 在书中使用的语言不乏愤怒和戏谑，但自始至终态度都非常理性，就如同她自己在文章中所说，是以一种“外来者”，而非爱好者的身份分析科幻写作。在知名的科幻作家当中，能够对自己所处的领域进行一番分析的屈指可数，而能有如此客观的态度和深刻的见解就更为难得。虽然 Le Guin 在今天肯定会对书中许多论点进行修正，但这本书对于今天刚踏入科幻作者行列的人们仍然是极具价值的。对于一般的读者而言，读完此书后也能对上世纪科幻小说“黄金时代”和70年代后的作品具有更深入的认识。
今天的科幻文学，比这本书里大部分文章写成的年代里的科幻小说，恐怕不能说有长足的进步，反倒显露出日渐式微的趋势。而在70年代，Le Guin 就观察到了这种现象，并将其归因于社会对快餐文化的追捧和功用主义对幻想的抵触，这个主题是这本书第一、第二部分的重点。除了社会的不认可，Le Guin 也指出在社会不将科幻作为主流文学看待的情况下，科幻作家们妄自菲薄，在写作时的态度有所欠缺，也是造成部分科幻小说文学性不强的原因，这是第三部分的主题。
Le Guin 在第四部分接着提出了她认为的好的科幻小说应具有的性质：文学性，科学上的可信性，以及艺术性。她在这部分也提出了她对新手开始科幻写作的观点。最后一部分，她鼓励科幻作家将自己的作品作为艺术来对待，不要用“仅仅是娱乐”来自嘲，也不要受到“市场审查”（Market Censorship）的影响，为迎合大众的口味炮制模板化、快餐式的小说。
书中贯穿始终的一个主题还包括女性主义的思想——虽然 Le Guin 本人在80年代的新版序言中也说这是70年代的女性主义——更多地主张男女平权而非提出一个女性视角，还有就是对幻想文学的艺术价值的肯定和对批评家们指责幻想是“escapism”的反驳。其实，虽然整本集子谈的都是科幻和奇幻，Le Guin 的主张——将作品看作艺术——对于其他创作，也是具有积极意义的提法。再推广一下，甚至也可以说工作和研究在一定程度上也需要这种态度。
Le Guin 在书中使用的语言不乏愤怒和戏谑，但自始至终态度都非常理性，就如同她自己在文章中所说，是以一种“外来者”，而非爱好者的身份分析科幻写作。在知名的科幻作家当中，能够对自己所处的领域进行一番分析的屈指可数，而能有如此客观的态度和深刻的见解就更为难得。虽然 Le Guin 在今天肯定会对书中许多论点进行修正，但这本书对于今天刚踏入科幻作者行列的人们仍然是极具价值的。对于一般的读者而言，读完此书后也能对上世纪科幻小说“黄金时代”和70年代后的作品具有更深入的认识。
2007年11月15日星期四
Graphical presentation of food/population dynamics
I encountered this article[1] when I am doing some search related to resilience and its mathematical methodology. In fact it is another way to explain Carpenter's S-shape curve in lake models[2]. I put the link here for future reference. Please note that the copyrights belong to [Resilience Alliance](http://www.resalliance.org/) and the author.
[http://www.ecologyandsociety.org/vol3/iss2/art11/figure7.html](http://www.ecologyandsociety.org/vol3/iss2/art11/figure7.html)
Ref:
1. Scheffer, Marten. 1999. Searching Explanations of Nature in the Mirror World of Math. Conservation Ecology 3, no. 2: 11. [Fulltext](http://www.ecologyandsociety.org/vol3/iss2/art11/manuscript.html)
2. Carpenter, Steve, Brian Walker, J. Marty Anderies, and Nick Abel. 2001. From metaphor to measurement: Resilience of what to what? Ecosystems 4, no. 8 (December): 765-781. http://www.springerlink.com/content/lu5mxqkxbblkly62/.
[http://www.ecologyandsociety.org/vol3/iss2/art11/figure7.html](http://www.ecologyandsociety.org/vol3/iss2/art11/figure7.html)
Ref:
1. Scheffer, Marten. 1999. Searching Explanations of Nature in the Mirror World of Math. Conservation Ecology 3, no. 2: 11. [Fulltext](http://www.ecologyandsociety.org/vol3/iss2/art11/manuscript.html)
2. Carpenter, Steve, Brian Walker, J. Marty Anderies, and Nick Abel. 2001. From metaphor to measurement: Resilience of what to what? Ecosystems 4, no. 8 (December): 765-781. http://www.springerlink.com/content/lu5mxqkxbblkly62/.
2007年11月9日星期五
More on GPS Visualizer: GE Overlays
I did some experiment with GPS Visualizer which I mentioned yesterday. I used it to visualise some Landsat images that I can use for my research.
In this screenshot you can see three overlays generated from Landsat visual images provided by [Jet Propulsion Laboratory, NASA](http://photojournal.jpl.nasa.gov/targetFamily/Earth). If you take a closer look at places where these images overlap you will find that the quality of registration is very impressive. However, GPS Visualizer seems not able to control the skewness of the image, all overlays are rectified to the latitude and longtitude, which is not the direction of Landsat's nadir path (shown in the image as a white line). Anyway, using it I can get an idea of the satellite coverage of my study area (red box) without using complicated GIS/RS software packages.
In this screenshot you can see three overlays generated from Landsat visual images provided by [Jet Propulsion Laboratory, NASA](http://photojournal.jpl.nasa.gov/targetFamily/Earth). If you take a closer look at places where these images overlap you will find that the quality of registration is very impressive. However, GPS Visualizer seems not able to control the skewness of the image, all overlays are rectified to the latitude and longtitude, which is not the direction of Landsat's nadir path (shown in the image as a white line). Anyway, using it I can get an idea of the satellite coverage of my study area (red box) without using complicated GIS/RS software packages.
2007年11月8日星期四
GPS Visualizer
[GPS Visualizer](http://gpsvisualizer.com/)
This is an essential for geography hobbists and serious GE users. Without a flashy interface (yet?), this site provides a rich set of tools to help you visualise geographic data on Google Maps and Google Earth. Haven't got time for all its features, but the first thing I am going to do with it is to create a Landsat overlay of my study area. More details in later posts.
This is an essential for geography hobbists and serious GE users. Without a flashy interface (yet?), this site provides a rich set of tools to help you visualise geographic data on Google Maps and Google Earth. Haven't got time for all its features, but the first thing I am going to do with it is to create a Landsat overlay of my study area. More details in later posts.
A Vision of Students
It's the first time I post a video clip to my blog. But believe me, I have seen hundreds and this one is standing out. Great shooting, skillful editing and thoughts provoking -- at least those of students and teachers.
I think it illustrates life of students in the U. S. and perhaps in U. K. quite well. Some facts even work for intl. students (like me).
2007年11月2日星期五
Grindhouse 很好玩
如果不带任何道德有色眼镜看这两个 back-to-back 的片子的话还是很有意思的。当然还要对 gory 有一定的承受能力才行……
昨天跟一群本科生挤在法学院的大教室里一起看的这个片子，屏幕不大，旁边的人狂吃薯片，果然很有 grindhouse 或者国内小录像厅的感觉。那几个 fake trailer 收获了最多的笑声，而正片的时候大家除了鼓掌就是不断的 "gosh" "yeeeesh~" 之类感慨了。
片子里有不少向老 B 级片致敬的片段……嗯，你要说是戏仿也行……Planet Horror 放到那个僵尸片流行的年代也应该是一部佳作。
如果你看的 Grindhouse 是两个片子各长 60 分钟的版本并且看完后没有任何不适感的话，推荐把两个片子的完整版本都找来看一遍，特别是 Death Proof。
昨天跟一群本科生挤在法学院的大教室里一起看的这个片子，屏幕不大，旁边的人狂吃薯片，果然很有 grindhouse 或者国内小录像厅的感觉。那几个 fake trailer 收获了最多的笑声，而正片的时候大家除了鼓掌就是不断的 "gosh" "yeeeesh~" 之类感慨了。
片子里有不少向老 B 级片致敬的片段……嗯，你要说是戏仿也行……Planet Horror 放到那个僵尸片流行的年代也应该是一部佳作。
如果你看的 Grindhouse 是两个片子各长 60 分钟的版本并且看完后没有任何不适感的话，推荐把两个片子的完整版本都找来看一遍，特别是 Death Proof。
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