Science – Page 97 – a sibilant intake of breath

Grass ( Fungus ( Virus ) Fungus ) Grass

There is increasing scientific awareness of the intricate and essential ways in which different organisms depend on one another biochemeically. Termites could not eat wood without bacteria in their digestive tracts. Humans are likewise dependent upon the huge variety of microorganisms that comprise our microbiome.

Dichanthelium lanuginosum takes such intricacy a step further. It is a grass that lives in very hot soils – such as those in Yellowstone Park. ot only does it depend upon a fungus for its heat resistance, that fungus depends in turn upon a virus. Remove either the fungus or the virus and the grass can no longer live in its ordinary niche. Apparently, something similar has been observed in some tomato plants.

The example demonstrates just how shockingly complex the combination of biochemistry, ecology, and evolutionary biology really is.

Source: Márquez et al. “A Virus in a Fungus in a Plant: Three-Way Symbiosis Required for Thermal Tolerance.” Science 26 January 2007: Vol. 315. no. 5811, pp. 513 – 515.

Reasons for vegetarianism

During the last few days, a number of people have asked about the reasons for which I am a vegetarian. As shown in the Venn diagram above, my reasons fall into three major clusters:

Hygienic concerns
Animal rights concerns
Ecological concerns

Basically, the first category applies if you only think about your own immediate well being. If you are willing to consider the possibility that it is wrong to treat some animals in some ways, considerations in the orange circle start to apply. If you accept that we have general duties to preserve nature (or recognize that our long term survival depends on acting that way), issues in the yellow circle are of concern.

The specific issues listed are just examples. They are not exhaustive representations of all the problems in each area. Possible reasons for being vegetarian also exist outside these areas: for example, you can think it is wrong to eat meat when the grain used to fatten the animals could have alleviated the hunger of other humans.

A few issues are unambiguously in one area – for instance, the de-beaking of chickens is almost exclusively an ethical problem. The fact that no experimental laboratory could get ethical approval to treat their test subject animals in the way factory farmed animals are treated as a matter of course is telling. Some overlaps are ambiguous. Overfishing destroys the habitats of species I consider us to bear moral duties towards (such as whales and dolphins), even if the fish themselves can be legitimately used as means to whatever ends we have.

Naturally, different kinds of meat and processes of meat production do more or less well in each area. For my own sake, I think each of the three areas is sufficient in itself to justify vegetarianism. It is possible to imagine meat production that doesn’t have any of these problems, but it is an extreme rarity today and my appreciation for meat is not strong enough to justify the cost and effort of seeking it out. That said, I would be much happier if people who were going to consume meat made such choices, instead of helping to perpetuate the machinery of modern industrial farming.

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.