Geek stuff – Page 90 – a sibilant intake of breath

Latent heat

This blog’s focus on matters of energy and climate frequently leads to discussions of thermodynamics. One aspect of that not yet mentioned is latent heat: the energy involved in phase changes of matter. While it takes 1 calorie (not one kilocalorie, as what people call food ‘calories’ are) to heat 1 ml (1 gram, 1 cubic centimetre – don’t you love metric) one degree Celsius, it takes a lot of energy to change that 1 mL of 100˚C water into 101˚C water vapour. Indeed, it takes 540 calories to induce the phase change (turning 1 g of ice into 1 g of water takes 80 calories).

An entertaining way to see this demonstrated is to watch Julius Sumner Miller (mentioned before) talk about temperature. Another is to watch an episode of James Burke’s The Day the Universe Changed: Credit Where It’s Due. As a bonus, it explains how religious dissenters helped to kick off the coal-fired Industrial Revolution in England, eventually generating the climate change problems that confront us so dauntingly now. There is also a fair bit of talk about banking, and the role it played in industrial development.

Electricity from evaporation

Previously, I tried to categorize all possible basic mechanisms for producing electricity. While I don’t think a recent invention by scientists working at Berkeley, MIT, and the University of Michigan uses any new principles, it is certainly a novel combination. Their artificial glass ‘leaves’ use ambient heat to move water, then exploit that to generate small amounts of electricity:

The leaf is transformed into a source of power by periodically interrupting the water flowing into the leaf with air bubbles. Thanks to the different electrical properties of air and water, every time a bubble passes between the plates the capacitance of the device changes and a small electric current is generated, which passes to an external circuit where it’s used to pump up the voltage on a storage capacitor.

While their prototypes produce minute amounts of energy (2 to 5 microvolts per bubble), the inventors hope that large trees made of these materials could generate electricity on the basis of changing humidity: something that could nicely counterbalance some of the variable output from wind or solar farms.

The research was published in Applied Physics Letters: Charge-pumping in a synthetic leaf for harvesting energy from evaporation-driven flows, Appl. Phys. Lett. 95, 013705 (2009); doi:10.1063/1.3157144, Published 7 July 2009.

Problems with revocable media

One of the biggest problems with the way information is now distributed is the increasing limitations on how you can use it. With physical media like books and CDs, you had quite a few rights and a lot of security. You could lend the media to friends, use it in any number of ways, and be confident that it would still work decades later. There is much less confidence to be found with new media like music and movies with DRM, games that require a connection to the server to work, mobile phone applications, Kindle books, etc. Companies have shown a disappointing willingness to cripple functionality, or even eliminate it outright, for instance with Amazon deleting books off Kindles. Steven Metalitz, a lawyer representing the RIAA, has stated explicitly that people buying digital media should not expect it to work indefinitely: “We reject the view that copyright owners and their licensees are required to provide consumers with perpetual access to creative works.” Of course, the same people argue that they should be able to maintain their copyrights forever.

The solution to this, I think, is to make it legal for people to break whatever forms of copy protection companies put on their products, as long as the purpose for which they are being broken is fair use. It also wouldn’t hurt to clarify the ownership of such materials in favour of users. A Kindle book should be like a physical book – property of the person that bought it, and not subject to arbitrary modification or revocation by the seller.

Of course, politicians are under more effective pressure from media companies than from ordinary consumers. Perhaps a strong Canadian Pirate Party, asserting the rights of content users over content owners, would be a good thing. Of course, stronger support from mainstream parties that actually hold power would be of much more practical use.

Spy photos of Arctic ice

A number of sources are reporting that the Obama administration has made public spy photos that show the effects of climate change in the Arctic. The photos have a one metre resolution, and were provided through a program called Medea which allows scientists to request intelligence images of environmentally sensitive areas.

With luck, the photos will allow climate models to be further refined: for instance, by better incorporating the positive feedback associated with changed albedo when white ice melts and is replaced by darker water. Other scientific information that could be derived from the photos includes: “the relationship of snow to ice-surface topography, the initiation and development of meltwater ponds in summer, and the relationship of stress and strain and how they are reflected in the pattern of cracks and other features in the ice.” Thorsten Markus – at NASA’s Goddard Space Flight Centre – has said that the key value of the new images lies in their high resolution, compared to those that were previously available.

Mistaken assumption about the politics of scientists

An interesting study reveals a disjoint in the United States between how scientists rate their political views and what the general public expects them to be. Whereas 56% of scientists describe themselves as liberal, along with just 2% as conservative and 42% as ‘neither,’ members of the general public surveyed expected 64% of scientists to answer ‘neither,’ 20% to be liberal, and 9% to be conservative. The study also found that scientists are less skeptical of government and more critical of business than members of the population at large.

The blogger commenting on the study predicts that two things would happen if people learned the truth:

“The public would consider scientists to be less authoritative as a neutral source on policy questions, and
Since scientists are respected, the public would become less conservative and more liberal.”

This raises some interesting questions about the relationship between expertise and legitimacy, in relation to the roles of scientists in decision making – the central topic of my M.Phil thesis.

Scan this with your camera phone

The above is an example of QR Code: a kind of two-dimensional barcode that can be used to encode any sort of textual data. As cameraphones and smartphones become more common in North America, you may see more and more of these. They are already common in Japan. Nokia has a website that lets you make your own mobile codes. You can make a simple business card like this:

URLs, phone numbers, and other sorts of information can be similarly encoded.

CRTC public submissions and privacy

Quite conveniently, the Canadian Radio-television Telecommunications Commission allows citizens to comment on ongoing matters through their website. Unfortunately, the privacy protections employed in relation to the submissions are lacking. Their website says the following:

The information you provide to the Commission as part of a public process (i.e. comments, interventions or observations) is entered into an unsearchable database dedicated to that specific public process. This database is accessible only from the webpage of that particular public process. As a result, a general search of our website with the help of either our own search engine or a third-party search engine will not provide access to the information which was provided as part of a public process.

This doesn’t seem to be true. Searching for my own name in Google brings up the submissions I made to them opposing Bell’s efforts to introduce Usage Based Billing (UBB). The submission includes my full name, personal email address, and phone number.

I complained electronically to the CRTC about this, but got no response. I then sent a letter to the Office of the Privacy Commissioner, with a carbon copy to them. At the very least, the CRTC should obscure email addresses and phone numbers in a way that prevents robots from harvesting them. For instance, obfuscated email addresses can be made to look normal for standard browsers, but like gibberish for most robots. Alternatively, the CRTC could provide a web contact form that lets people contact submitters, without learning their email address. I have no problem with submissions being made public, in the interest of transparency. If it is going to happen, however, people should be clearly informed about it on the page where they submit the information (not some separate privacy information page) and reasonable efforts should be taken to prevent the inappropriate collection of personal information by either people or automated systems.

[Update: 7 August 2009] The CRTC responded to my complaint, and it seems they have come into compliance with their privacy policy.

Defining timeframes

For the sake of clarity, I am going to try to use the terms ‘near,’ ‘medium,’ and ‘long’ term in a consistent way in future posts about climate change:

Near-term: within the next ten years
Medium-term: within the next fifty years
Long-term: within the next hundred years

For instance: developed states need to establish strong domestic carbon prices in the near term. In the medium term, they need to get very close to carbon neutrality (perhaps with emissions 95% below 1990 levels). In the long term, the entire planet needs to be basically carbon neutral.

When referring to phenomena where the relevant timescale is different (shorter, for politics and quantum mechanics; longer for geology), I will try to use numerical estimates rather than the near-medium-long descriptions.

Sci-fi as a prescriptive genre

Science fiction may be the most prescriptive fictional genre. Firstly, it forces people to consider the consequences of actions and choices across a long timespan. Secondly, it helps to reveal the core ethical values people have: it presents both our aspirations and things that inspire fear, disgust, and outrage. Finally, it makes statements about contemporary ideologies by presenting them with false hindsight.

As such, though sci-fi has a sometimes deserved reputation as an escapist genre, it can also be among the most directly ethically and politically engaged. It also serves a historically valuable purpose, by revealing how those in the past imagined the future. For instance, look at Asimov’s projection that everything would be nuclear-powered in the distant future, even small toys for children. It is no surprise that today’s sci-fi has ecology as a key focus. It would be fascinating to know how it will be read in a century.

Carbon-neutral aviation

The climatic impact of aviation

At present, virtually all freight and passenger-carrying aircraft operate in one of two ways: burning kerosene to turn a propeller, generating thrust that the wings partially convert to lift, or generating thrust by burning kerosene in a jet engine. Virtually all of that kerosene is produced by refining petroleum. As such, burning it adds to the stock of greenhouse gasses in the atmosphere. These include carbon dioxide (CO2) (a basic product of the combustion) and other greenhouse gasses (GHGs), like nitrous oxide (NO2). It is also possible that aircraft have an effect on cloud formation (both by producing vapour trails and inducing cirrus cloud formation), but my understanding of the science is that scientists aren’t sure whether that has a net warming or a net cooling effect. The latest IPCC report says:

Moreover, the uncertainties on some aviation forcings (notably contrail and cirrus) are still high, such that the overall radiative forcing consequences of changing cruise altitudes need to be considered as a time-integrated scenario, which has not yet been done. (p. 355)

Helpfully, the report does identify that, if contrails prove to be a significant problem, they “can be easily avoided – in principle – by relatively small changes in flight level, due to the shallowness of ice supersaturation layers.” There is also some uncertainty about the relative emissions of short-lived but potent GHGs like nitrous oxide, compared with long-lived but less potent ones like carbon dioxide. All told, the report does conclude that aviation has a “larger impact on radiative forcing than that from its CO2 forcing alone.”

Carbon neutral possibilities

A couple of logical possibilities exist for making air travel carbon-neutral, though they differ in practicality. Electric planes are conceptually possible, and small versions exist. As I understand it, the big problem is storing enough energy in light enough batteries. My sense is that we are nowhere near being able to do this for large commercial aircraft. Similar issues exist for hydrogen aircraft, in term of storage, and there is the added question of where we get the hydrogen. To me, biofuels seem like the most plausible near-term option. That being said, there are technical issues to be overcome within aircraft themselves, such as the gelling of biofuels at the low temperatures found at high altitudes. While some airlines have tested multi-engine planes with a single engine running on a biofuel/kerosene mix, as far as I know nobody has flown such a plane exclusively using biofuels.

Additionally, not all biofuels are carbon neutral. Ethanol derived from corn might actually represent more greenhouse gasses than an equivalent amount of gasoline, once you factor in fertilizer production, emissions from farming and farm equipment, ethanol fermentation, etc. The same might be true of palm oil derived biofuels, given how their production can lead to the destruction of rainforests that are major carbon sinks.

My sense is that the air travel industry has yet to demonstrate that it will be able to exist in a carbon neutral world, regardless of how expensive tickets become. That being said, it does make sense to displace emitting activities in order from lowest cost to highest cost. If we can replace fossil fuelled ground vehicles with electric vehicles running on renewable power, we should do so first before pouring enormous effort into trying to produce a carbon neutral aircraft. That being said, there does seem to be a strong moral imperative to reduce emissions generally, including by limiting the amount of long-distance travel we undertake.

As usual, I expect any mention of aviation to produce a lively discussion.