Category: Geek stuff

If it involves physics, math, computer science, electronics or has general geek cachet, this is the place for it.

Arctic sea ice volume

I expected Alun Anderson’s After the Ice: Life, Death, and Geopolitics in the New Arctic to mostly contain information I had seen elsewhere. In fact, it is chock full of novel and interesting details on everything from marine food webs to international law to oil field development plans. I read the first 200 pages in one sitting.

One chapter goes to some length in describing how we know what we do about Arctic sea ice volume. It is harder to measure than the extent of sea ice, which can be observed in all sorts of ways by satellites (optical instruments, synthetic aperture RADAR, passive microwave emissions, etc). One effort to estimate how ice volume is changing was based on multibeam SONAR on submarines. An 11 day survey conducted by Peter Wadhams, using the nuclear-powered HMS Tireless concluded that 40% of Arctic sea ice has been lost since the 1970s. Another team, led by Drew Rothrock, used previously secret US submarine data to confirm that figure for all areas that submarines have been visiting.

Anderson also describes the importance of the cold halocline layer: a thin layer of cold water that insulates the bottom of Arctic ice from the warmer Atlantic waters underneath. Without this layer, multiyear Arctic ice would be doomed. For a number of reasons, climate change threatens to undermine it. If it does, the complete disappearance of summer sea ice could occur faster than anyone now expects.

There are many reasons to worry about the vanishing Arctic ice, from the increased absorption of solar radiation that accompanies lost albedo to the danger of invasive species entering the Atlantic from the Pacific. I’ve written previously about ‘rotten’ ice, and many other issues in Arctic science.

Those much-hyped ‘Bloom Boxes’

Now that some figures are on their website, it is possible to comment a bit more meaningfully on Bloom Energy (beyond noting that they can attract a lot of heavyweights to their press events).

They seem to have deployed 3 megawatts of fuel cells in seven installations. That’s twice as much power as is provided by Grouse Mountain’s solitary wind turbine. Of these, two installations (with an output of 900 kW) are running on methane from renewable sources. According to Wikipedia, the fuel cells cost $7,000 to $8,000 per kilowatt. That is extremely high. An open cycle gas turbine power plant costs about $398 per kilowatt. Wind turbines cost something like $1,000 per kilowatt. Nuclear is probably over $2,000 and even solar photovoltaic is cheaper than $5,000. From an economic perspective, natural gas also isn’t the most appealing fuel for electricity production. It has significantly higher price volatility than coal.

Without more statistics, it is impossible to know how the efficiency of these fuel cells compares to conventional natural gas power plants, either before or after transmission losses are factored in. Bloom’s literature says that, when they are using conventional natural gas, emissions from their fuel cells are 60% lower than those from a coal power plant. Frankly, that isn’t terribly impressive. Coal plants generate massive amounts of CO2, relative to their power output. It also isn’t clear whether methane from renewable sources would be more efficiently used in these distributed fuel cells than in larger facilities based around turbines and combustion.

Many environmentalists assume that distributed power is the future, but there are definitely advantages to large centralized facilities. They can take advantage of economies of scale and concentrated expertise. They may also find it easier to maintain the temperature differential that establishes carnot efficiency.

It will be interesting to see how Bloom’s products stack up, when more comparative data is available.

Wave Hub

Despite moderate potential, wave power is one form of renewable energy that hasn’t really gotten off the ground yet. One project in Cornwall is helping to change that. Wave Hub will test four different kinds of equipment for converting wave energy into electricity, producing 20 megawatts of power in the process.

The equipment will be about ten miles offshore.

David MacKay estimates that the UK could deploy as much as 1,000km of wave power generators, yielding four kilowatt-hours per day for each person in the UK. That’s small beans beside the 116 kilowatt-hours that people in the UK actually use, but we need to be looking into all available renewable options.

Best books of 2009

Back in 2007, I put up a post listing my five favourite books of the year. Somehow, I missed 2008. Despite that, I am still happy to assert that the 2007 list includes some of the best books I have ever read.

Among the books I read in 2009, these are the five I most emphatically recommend:

It was a tough choice.

Margaret Atwood’s The Year of the Flood would be a natural successor to Oryx and Crake back in 2008. Unfortunately, the better book of the two remains the original.

If I had read Jared Diamond’s Collapse: How Societies Choose to Fail or Succeed soon after it had come out, it might have been one of my choices. That said, it is a compelling and important book.

Richard Dawkins’ The Greatest Show on Earth: The Evidence for Evolution certainly deserves a nod. For anyone who wants a comprehensible account of why we know as much about evolution as we do, this is the book to read.

You can read all my book reviews here.

I may eventually cook up a retroactive 2008 list.

BoingBoing stands up to a SLAPP

It’s nice to see the initiators of a frivolous or abusive lawsuit get their comeuppance. In this case, I am referring to the failed attempt by MagicJack to silence criticism through a strategic lawsuit against public participation (SLAPP) against BoingBoing and blogger Rob Beschizza. Too often, faced by the high costs of going to court and the danger of losing, people who had been legitimately expressing an honestly held opinion (often one protected by constitutional law) are bullied into withdrawing their statement, or even paying a settlement. This is a particular danger in states that have terrible libel laws, like the United Kingdom. It is sad but understandable when firms take the safe course – such as when SuicideGirls when through their bout of unprovoked self-censorship. When someone has the guts to fight back, they deserve public recognition and support.

As such, kudos to BoingBoing and Mr. Beschizza. The $50,000 in legal costs they recovered aren’t enough for them to break even, but their example may have public value in deterring some future SLAPPs. There are strong positive externalities that result when organizations like BoingBoing take the courageous course and succeed. Such outcomes help to remind others that free expression is a vital aspect of free and democratic societies, and that attempts to suppress it through legal threats are inappropriate and anti-democratic. They also make it clear to potential filers of SLAPPs that they may end up with even more public embarrassment at the end of the process than they started out with.

Evaluating existing climate change information

This may strike some people as abstract, but perhaps it will be of interest to someone.

Assume, to start with, that climate change is a major threat to humanity and that concerted global effort is required to deal with it. In that case, I see two possibilities:

  1. If all of humanity and all human knowledge were put in an abstract place together and given all the time they needed to educate one another, consider the data, and deliberate, they would come to a conclusion that strong climate change mitigation action ought to be undertaken.
  2. Even with all our current information and unlimited time, this conclusion could not be widely endorsed. It may, however, be the case that the people in this abstract space would reach the conclusion that we must act, if only they had some new information that we have not yet observed or collected.

Part of the answer involves the depths of human ideological and theological beliefs. If there are people who can never be shaken in their belief that the world is benevolent and concerned about humans, they could never be convinced otherwise by education or information. Part of the answer may have to do with the overall relationship in human beings between perceived risks and the willingness to take precautionary action. That said, I am convinced that an impartial assessment of climate science and the situation we are in would lead most any rational human being to endorse a precautionary approach.

I am similarly convinced that people in my ideal case would eventually overwhelmingly support aggressive mitigation actions. I don’t think human beings would be happy to expose all future generations to the risk of misery and possible extermination, just so they can avoid a transition to renewable energy that would be necessary regardless of climate change, and which can probably be accomplished for a few percent of GDP, spread over many years.

Of course, the real world is very different from my little imagined experiment. Time is important here. If climate change deniers can keep the public confused for another 20 years, that will have a huge impact, even if they could eventually have been unmasked as self-interested charlatans in my infinite-time case. Time can also work to our advantage, however. Striking new information can come to light and, in so doing, it can have an effect on what beliefs and priorities people hold faster than old information would be able to do in an education-and-discourse manner. For example, if we were to observe a drought of unprecedented scale and severity, it might have a big impact on the willingness of people to endorse the kind of high-level policies and actions necessary to curb the harmful influence of human beings on climate (or perhaps not).

What do you think? Would people reach a consensus in favour of strong mitigation action, given all the information and infinite time? If not, what further information might they require? In either case, what is the effect of the differences between my ideal infinite-time case and the real world, in which our choices in the next couple of decades will do much to determine where the climate ends up?

Xyloexplosive devices

The funniest videos to watch backwards are those in which entropy increases a lot: things like explosions and toppling dominoes, where it is completely obvious that the order of the video frames has been reversed. By contrast, something like a bouncing ball is pretty boring to watch backwards.

Tom Stoppard’s play Arcadia features some good discussion of entropy, and reactions that cannot be reversed. It is easy enough to stir jam into pudding, but impossible to unstir it back out. In addition to showing us something about the nature of time in our universe, it is a decent metaphor for why human regret can be counterproductive. You can’t unstir the pudding, after all.

Enterprising geeks have cooked up an entertaining new way to rapidly increase the entropy of a bunch of popsicle sticks or tongue depressors. It’s like a more energetic version of dominoes, and well worth a look both forwards and backwards.

Put crosswalks between intersections

The other day, I was crossing the street in the middle of the block, listening to a small voice of conscience chiding me for the ‘dangerous’ act. Then I realized that I had actually chosen to walk partway up the block, rather than using the crosswalk, and that my primary reason for doing so was my own safety.

Intersections try to combine two purposes that mesh poorly: allowing pedestrians to cross roads and allowing drivers and cyclists to make turns. It is obvious that these two goals conflict. People crossing the street don’t want vehicles passing through their area of travel – especially vehicles that move in unexpected directions and at unpredictable speeds. Cars making left-hand and right-hand turns tend to do both.

Perhaps it makes sense to divide these two purposes, then. Put stoplights in the middle of blocks and let pedestrians cross there, leaving intersections exclusively for turning. It might slow down the flow of traffic a bit, but I am actually in favour of moves to make driving less convenient in cities. It would make life safer for pedestrians, by making the crosswalk unambiguously their space when the light is in their favour, and the slowdowns caused by the potential lights would be partially made up for by freeing drivers from having to worry about pedestrians when making turns.

Sure, it would be better to reserve city centres entirely for people on foot, bicycles, and public transit vehicles. This plan is less radical, won’t generate the same outrage from big box stores, and may well save some lives.

Seeking certainty about climate change

I have written before about the problem of what can and cannot be known about climate change, given that we only have one planet to experiment on, and our simulations will never be accurate beyond question. Here is another expression of the same basic idea. I am trying to figure out the most effective way to convey this information to people who don’t think we should be taking aggressive action on climate change.

This chart shows four possible situations that humanity could find itself in, 100 years or so from now. Either climate change has been disastrous or it has not been, and we either took strong action to deal with it or we did not:

As you can see, there is only one situation in which we can be absolutely sure we made the right choice. Even that is a bit ambiguous, though. Imagine the decision isn’t about climate change but about Russian Roulette. If we are alive after the game, but we did choose to play, can we really be said to have behaved prudently? The sheer fact that the chamber didn’t turn out to be loaded doesn’t mean that we were intelligent to run the risk, back when we didn’t know that for sure.

Imagine two snakes, both of which look very similar. One is deadly venemous, and the other is benign. If the best information we have at hand suggests that there is a good chance we are dealing with the venemous one (say, because we are in the region where it usually lives), the prudent thing is certainly to behave as though the snake may be venemous. Even if you learn later that it was not, nobody will think you were a fool for acting that way. The climate science we have now is providing good reasons to think that we are dealing with a deadly snake of a problem.

In short, the science will never be settled in the sense that it will tell us exactly what to do. All it can do is become clear enough to make the prudent choice obvious to most people.

Degrees of frost

For practicality, you can’t beat the Celsius temperature scale. Were it not for the stubbornness of Americans, the weird Fahrenheit alternative (initially established with ice, brine, and an armpit) would be long-gone. For scientists, the Kelvin scale lets you represent temperature appropriately for thermodynamic calculations, and helpfully retains the same unit size as Celsius.

I would have thought the case would be closed there, but Bill Streever’s book made me aware of a more romantic-sounding alternative: degrees of frost. This temperature measure – a favourite of penguin-egg-gatherer and Antarctic explorer Apsley Cherry-Garrard – measures how many degrees it is below the freezing temperature of water.

Naturally, I prefer the Celsius version, though it sounds a bit less dramatic. Right now, it is a completely tolerable -4˚C in Ottawa. That’s just four degrees of frost – nothing to compared to the 60.8 degrees of frost experienced by Cherry-Garrard. The worst I’ve seen in Ottawa is about thirty degrees of frost, during my first frozen winter in Ottawa. Wind chill, incidentally, is not really a very scientific thing.