Science – Page 98 – a sibilant intake of breath

A few thoughts on climate justice

A couple of articles at Slate.com address the issue of ‘climate justice.’ This is, in essence, the question of how much mitigation different states are obliged to undertake, as well as what sort of other international transfers should take place in response to climate change. The issue is a tricky one for many reasons – most importantly because anthropogenic greenhouse gas emissions constitute a unique experiment that can only be conducted once. If we choose the wrong collection of policies, all future generations may face a profoundly different world from the one we inherited.

If we accept Stern’s estimate of a five gigatonne level for sustainable global emissions, that works out to about 760kg of carbon dioxide equivalent per person on Earth. Releasing just 36kg of methane would use up an entire year’s allotment, as would just 2.5kg of nitrous oxide. One cow produces about 150kg of methane per year. Right now, Canada’s per-capita emissions are about 24,300kg, when you take into account land use change. American emissions are about 22,900kg while those of India and China are about 1,800kg and 3,900 respectively. Because of deforestation, Belize emits a startling 93,900kg of CO2e per person.

The questions of fairness raised by the situation are profound:

Should states with shrinking populations be rewarded with higher per capita emissions allowances?
Should states with rising populations likewise be punished?
Should developing states be allowed to temporarily overshoot their fair present allotment, as developed states did in the past?
To what extent should rich states pay for emissions reductions in poor ones?
To what extent should rich states pay for climate change adaptation in the developing world?

It may well be that such questions are presently unanswerable, by virtue of the fact that answers that conform with basic notions of ethics clash fundamentally with the realities of economic and political power. We can only hope that those realities will shift before irreversible harmful change occurs. Remember, cutting from 24,600kg to 760kg per person just halts the increase in the atmospheric concentration of CO2. The level of change that will arise from any particular concentration remains uncertain.

Another vital consideration is how any system of international cooperation requires a relatively stable international system. While it is sometimes difficult to imagine countries like China and the United States voluntarily reducing emissions to the levels climatic stability requires on the basis of a negotiated international agreement, it is virtually impossible to imagine it in a world dominated by conflict or mass disruption. It is tragically plausible that the effects of climate change could destroy any chance of addressing it cooperatively, over the span of the next thirty to seventy years.

Salmon farming and sea lice

Recent work by Martin Krkosek of the University of Alberta has demonstrated strong links between the practice of salmon aquaculture and the incidence of sea lice infestations that threaten wild populations. One study used mathematically coupled datasets on the transmission of sea lice (Lepeophtheirus salmonis) on migratory pink (Oncorhynchus gorbuscha) and chum (Oncorhynchus keta) salmon. They concluded that:

Farm-origin lice induced 9–95% mortality in several sympatric wild juvenile pink and chum salmon populations. The epizootics arise through a mechanism that is new to our understanding of emerging infectious diseases: fish farms undermine a functional role of host migration in protecting juvenile hosts from parasites associated with adult hosts. Although the migratory life cycles of Pacific salmon naturally separate adults from juveniles, fish farms provide L. salmonis novel access to juvenile hosts, in this case raising infection rates for at least the first 2.5 months of the salmon’s marine life (80 km of the migration route).

Packing fish together in pens that are open to the sea is an almost ideal mechanism for breeding and distributing parasites and disease. In nature, you would never find salmon packed 25,000 to an acre. Keeping them in such conditions – and making them grow as quickly as possible – generally requires chemical manipulation. The earlier discussion here about antibiotic use and its role in the emergence of resistant bacteria is relevant.

These concerns also exist in addition to the fundamental reason for which fish farming cannot be sustainable: it relies on catching smaller and less tasty fish to feed to the tastier carnivorous fish that people enjoy. It thus lets us strip the sea bare of salmon or cod or trout and compensate for some period of time by using cheaper fish as a factor for their intensive production. Given that those cheaper fish are caught unsustainably, however, fish farming simply delays the emergence of truly empty oceans. And the industry is trying to have farmed salmon labelled ‘organic.’ Ludicrous.

Source: Krkosek, Martin et al. “Epizootics of wild fish induced by farm fish.” Proceedings of the National Association of Sciences. October 17, 2006, vol. 103, no. 42, 15506-15510.

P.S. Shifting Baselines also has some commentary on sea lice and salmon farming.

Entertaining physics demonstrations

His name is Julius Sumner Miller and physics is his business.

For those who lacked my good fortune in seeing most of these demonstrations a number of times at Vancouver’s Science World, the videos should give a sense of how physics can be made universally comprehensible and exciting. The facts that Mr. Miller looks like a mad scientist and that he has a penchant for hyperbole may well contribute to his ability to hold one’s attention.

My involvement as a camper and leader at SFU’s Science Alive daycamp also impressed upon me the effectiveness of physical demonstrations in sparking children’s interest in science. That is especially true when the demonstrations involve rapid projectile motion, strong magnets, cryogenic materials, aggressive combustion, and explosions.

Geminid meteor shower

Those of you with clear skies should make a point of peering at them tonight. The shower – produced by debris from a near-Earth asteroid called 3200 Phaethon – should become increasingly intense throughout the night, peaking in intensity around dawn. According to NASA, this should be the best meteor shower of the year. It may well be worth getting up before dawn (or staying up especially late) and looking to the western sky.

3200 Phaethon is thought to be a former comet, dust from which began intercepting Earth’s orbit annually during the American Civil War. The object is about 5 kilometres wide and misses the earth by only 2 million kilometres. If you have access to a decent telescope (many university observatories are open to the public some nights), you can observer Phaethon in the constellation Virgo. It only has the brightness of a 14th magnitude star, so neither the naked eye nor binoculars are sufficient to pick it out.

Climate and the boreal forest

According to data submitted by Global Forest Watch Canada to the International Boreal Conservation Campaign (IBCC), Canada’s boreal forest contains 186 gigatonnes of carbon dioxide equivalent. That is equal to about 27 years worth of present global emissions. Permafrost – which is rich in methane – makes up about 25% of the world’s land area and about 50% of Canada.

Significant permafrost melting would release gasses that would accelerate the warming trend. Making boreal areas into parks and avoiding deforestation there isn’t a terribly effective mechanism for keeping the bulk of these greenhouse gasses in the soil. The trees themselves are increasingly threatened by pine beetles, as warm winters permit their continued spread. Maintaining the soils as a carbon sink essentially requires that they remain cold – an increasingly distant prospect as emissions continue to grow and other carbon sinks become saturated.

No Arctic summer ice in 2012-13?

According to a BBC article, some scientists are predicting the disappearance of all Arctic summer ice within five to six years. This projection is based on computer modeling by Wieslaw Maslowski and uses data that doesn’t even take into account the spectacular loss of Arctic ice last summer. Maslowski’s team has produced an estimated rate of loss much higher than those of other groups who have studied the issue, but he defends the quality of his modeling:

“We use a high-resolution regional model for the Arctic Ocean and sea ice forced with realistic atmospheric data. This way, we get much more realistic forcing, from above by the atmosphere and from the bottom by the ocean.”

Even the work of other teams suggests the loss of summer ice between 2040 and 2100: a very rapid climatic change, given how most forms of natural climatic forcing operate on the timescale of millennia

The progressive deterioration of the northern polar cryosphere is disturbing for a number of reasons. Because water absorbs more energy from sunlight than ice does, the loss of the icecap would accelerate global warming. It would also eliminate or substantially alter the lifestyles of those living in the north, as well as most Arctic species. That said, there is some chance that the sudden disappearance of the Arctic icecap would be dramatic and irrefutable enough to kick off much more serious global action to mitigate greenhouse gas emissions and prepare to adapt to the amount of change that is now inevitable. In a world where the Arctic vanished before our eyes, radical ideas like those of Monbiot may start seeming reasonable to a lot more people.

Another climatic threat: jökulhlaups

In some parts of the world, large lakes are bounded by natural dams made of glacial ice. When the ice melts, the resulting surges of water are comparable in effect to the failure of human-made dams. Merzbacher Lake, in Kyrgyzstan, has completely emptied 39 times, following such events. An article in Geophysical Research Letters describes that lake in greater detail.

Significant past examples of such glacial lake outbursts occurred in Iceland, Alaska, Canada, and Bhutan. While relatively few areas are threatened by such events, they are demonstrative of the kind of change that is ongoing in the cryosphere.

Tsho Rolpa, a glacial lake in Nepal, seems to be due for such an event. It is 4580m above sea level and dammed by 150m of ice. The melting of the Trakarding Glacier is feeding the growth of the lake, which will eventually breach the ice wall in a highly dramatic manner. Local communities have been building raised watchtowers and shoring up embankments. Tsho Rolpa is one of 2,323 glacial lakes in the Nepalese Himalayas.

The eradication of smallpox

On this day in 1979, the World Health Organization certified that smallpox had been eliminated from the wild. It was probably the only intentional extinction in human history, and it was a considerable boon to the human race. The disease is an atrocious one, and it took a heavy toll across history. Notably, it caused much of the death associated with the arrival of Europeans in North America.

The extinction raises a number of questions. One is whether it will ever be repeated. We came close with polio. Very few people would mourn the elimination of tuberculosis, malaria, or AIDS. Worldwide eradication requires global coordination – something very hard to bring about when territories exist outside the control of any state. Think of the tribal areas bordering Pakistan and Afghanistan.

Another issue has to do with smallpox itself. It was horrifically destructive to the First Nations because they lacked any of the immunity conferred by prior exposure. Now, the whole world is in essentially the same boat. An intentional or accidental release of the weaponized smallpox produced by many states could thus cause of devastating global pandemic. It rather makes one wish we had never turned it into a weapon in the first place.

Meat and antibiotics

Quite a while ago, I wrote about connections between human disease and the factory farming of animals. Recently, some new observational data has supported the link between the two. In the Netherlands, a new form of the superbug MRSA has emerged. It is strongly resistant to treatment with tetracycline antibiotics: a variety heavily used on livestock. The animals need the drugs because they are kept in such appalling conditions (unhygienic and constrained) that they would get infections too easily otherwise.

Xander Huijsdens and Albert de Neeling found that 39% of pigs and 81% of pig farms in the Netherlands were hosts to the potentially lethal antibiotic resistant bacteria. People who came into contact with pigs were 12 times more likely to contract this form of MRSA than members of the ordinary population; those who come into contact with cattle are 20 times more susceptible. The strain has since been found in Denmark, France, and Singapore. A study conducted by the University of Guelph found the strain in 25% of local pigs and 20% of pig farmers.

Maintaining the effectiveness of antibiotics for the treatment of people is highly important for human welfare. Antibiotics are one of the major reasons why modern medicine is valuable: they help people die dramatically less often after childbirth and surgery than was the case before their development. They have also helped to make diseases that would formerly have been probable death sentences treatable. The fact that we are allowing farms to deplete their value so that they can produce meat more cheaply (by forcing more animals closer together in less clean conditions) seems profoundly unwise. In Pennsylvania, legislators have even banned farmers who produce hormone and antibiotic milk from saying so on their packaging – on the grounds that it would make consumers unduly worried about the other milk on offer.

Passionate Minds

I started Passionate Minds: The Great Love Affair of the Enlightenment, Featuring the Scientist Émilie du Châtelet, the Poet Voltaire, Sword Fights, Book Burnings, Assorted Kings, Seditious Verse, and the Birth of the Modern World with high hopes. It promised science, literature, and history in an accessible package. That promise is only partially realized. While the book does reveal some of the most remarkable (and the most flawed) characteristics of both Voltaire and du Châtelet, it sometimes makes claims that stretch the evidence provided. Often, the book simply asserts things rather than seeking to prove them.

Bodanis’ central thesis – that Émilie du Châtelet has been given insufficient historical attention – is fairly robust. Clearly, hers was an extraordinary life: born into nobility, but driven towards science and the sometimes hapless literary life of Voltaire instead of occupying a more traditional position in the Court. At times, the book demonstrates startling contrasts between the way of life at the time and the present. This is especially true of the marriages: purely political and economic unions in which years of habitation with a prominent lover were apparently not too exceptional. When a court rival attacks Voltaire through a lawsuit, her husband comes to his defence – despite how Voltaire has been living with his wife for years and they are a highly prominent couple.

In the end, the book would have been better if it had focused less on intrigue and more on what significant scientific contributions du Châtelet actually made. Saying that “[m]ore technical aspects of her work played a great role in energizing the French school of theoretical physics, associated with Lagrande and Laplace” isn’t a very convincing way of showing historical importance. Likewise, the assertion that “[t]he use of the square of the speed of light, c², in Einstein’s most famous equation, E=mc² is directly traceable to her work” is never adequately argued.

The book does an excellent job of describing how atrocious the medicine of the time was, contributing to du Châtelet’s own relatively early death in childbirth. It also relates some fascinating historical episodes in an engaging way: for instance, the rigged lottery through which Voltaire made his fortune.

A book about du Châtelet written by someone with more of a focus on studying and explaining science would be a better tribute to the woman than this interesting yet flawed volume.