Science – Page 65 – a sibilant intake of breath

Math and sea ice

Over at Eureka Science News, there is an interesting post about mathematical insights into sea ice dynamics. It describes work done in the mid-nineties by mathematician Ken Golden, who realized that sea ice shares certain mathematical characteristics with the powders used to make stealth materials for military vehicles:

His model captured one of the key features of sea ice: When the volume of brine is under about 5 percent, the sea ice is impermeable to fluid flow. But when the brine volume passes that critical 5-percent threshold, the sea ice suddenly becomes permeable to fluid flow. This 5-percent threshold corresponds to a critical temperature of -5 degrees Celsius for a typical bulk salinity of 5 parts per thousand. At first Golden did not quite realize what a breakthrough this work represented. “It was just a cool observation, with the comparison to stealthy materials,” he remarked. “I didn’t realize how important it was at the time.” But today, polar scientists routinely refer to the “rule of fives” that emerged from Golden’s work.

Hopefully, such work will eventually help us reach a much higher level of understanding of icesheet dynamics and the relationships between climate change, ice, and the oceans.

Space-based solar power

The Pacific Gas and Electric Company is seeking regulatory approval for a space based solar power system. The plan is for a 200 megawatt (MW) facility that will generate electricity from sunlight in orbit and beam it to a ground receiving station using radio waves. Older gamers may recall this technology as the basis of the ‘microwave’ power plants in SimCity 2000. Unfortunately, while the SimCity plants cost just $30,000 and produced 14,000 MW of energy, the 200 MW PG&E facility is expected to cost several billion dollars – far more than ground-based facilities with comparable output. The one real perk of space-based systems in geosynchronous orbits is that they will be exposed to the sun at all times, eliminating the need for storage or load balancing. Some have even speculated that the technology might eventually be able to direct beams of energy directly to facilities (perhaps even vehicles) that require it, reducing the need for transmission and energy storage infrastructure.

I am not sure how to feel about such initiatives. On the one hand, it is possible that space-based solar power will eventually be a commercially and ecologically viable source of energy. On the other, it may be a distraction from the urgent changes that need to occur in the near-term. There are also issues with the emissions associated with space launches, as well as the limited number of slots for satellites in geosynchronous orbit and ‘optical aperture’ issues. For now, it really doesn’t seem like a viable technology. That being said, if a private group can convince regulators that it is safe and environmentally effective, and investors that it is viable, I don’t see any reason to interfere with the attempt.

GMOs not providing yield or climate change benefits

The Union of Concerned Scientists has a new report (PDF) out, arguing that genetic modification of crops has so far failed to increase yields or improve resilience to climate change. The study covers the period of the past fifteen years, during which GM crops have been widely commercially deployed in the United States and elsewhere. It focuses on corn and soybeans, since they are the most commonly-grown GM crops. 90% of American corn is GM, as are 64% of soybeans.

The report also highlights how GM crops are heavy users of nitrogen-rich synthetic fertilizers, and that their use generates nitrous oxide in soil, a powerful greenhouse gas. Producing fertilizer also requires energy and generally uses natural gas as a feedstock.

The report concludes that GM is being over-invested in, relative to conventional breeding techniques and approaches that minimize the use of external inputs. I have argued in the past that genetic modification could be one tool for helping to adapt to a changed climate, and I think that is still true. What this study shows is the importance of rigorous evaluation, as well as somewhat tempered enthusiasm when it comes to the ability of new technologies to yield strong, rapid changes in outcomes.

Diatoms as solar cell material

Scientists in Oregon are working on a process to make solar panels with the help of single-celled marine organisms called diatoms. By providing the diatoms with titanium dioxide, rather than the silicon dioxide with which they normally make their shells, a material is produced that can be rendered photovoltaic through the application of dyes. Supposedly, this material is three times more efficient than similar dye-based thin-film cells made without the diatoms. While the resulting cells are still experimental, and more expensive than conventional thin-film dye cells, the possible efficiency gains may eventually render them more commercially viable and effective, especially in situations of relative low light.

Certainly, microorganisms are a sensible place to look if you want to be able to consistently produce precise nanoscale structures. Hopefully, techniques like this will speed the pace at which renewably generated power displaces that from fossil fuels.

Lost Antarctic ice bridge

The BBC is reporting that a stretch of ice between the Charcot and Latady islands has collapsed. Further, the bridge was apparently an important structure holding the remaining portion of the Wilkins Ice Shelf in place. The shelf, which is the size of Jamaica, has been suffering major recorded losses since 2008, and its total disappearance would represent the largest loss of ice in the Antarctic region in recorded history.

Three satellites are monitoring the shelf either daily or more often: the European Space Agency’s Envisat, and NASA’s Terra and Aqua satellites. Uncertainty about the ice dynamics of western Antarctica is a major source of uncertainty in projections of future sea level rise associated with climate change.

Adapting to +4˚C

New Scientist has an interesting piece on what might be involved in adapting to a 4˚C increase in mean global temperature – a level twice that considered by most to be the threshold of danger. Some of the more dramatic projections include: “Alligators basking off the English coast; a vast Brazilian desert; the mythical lost cities of Saigon, New Orleans, Venice and Mumbai; and 90 per cent of humanity vanished.” The piece rightly stresses that the adaptation challenge depends on both the speed of change and the degree, and that some levels of climate change are not compatible with maintaining populations or civilizations comparable to those that exist today. It focuses intensely on water availability as a key determinant for the habitability of large parts of the globe.

While the details of this assessment are far more speculative than the science that shows a 4˚C rise to be possible, given continued fossil fuel use, it does seem worthwhile to be seriously contemplating what different future scenarios might involve. On the one hand, doing so might help us prepare. On the other, it should help us more viscerally comprehend the consequences of inaction.

Dark Sun

The whole technical and chilling history of atomic weapons is reviewed in Richard Rhodes’ Dark Sun: The Making of the Hydrogen Bomb. Released in 1995, it is based substantially on documents that became available after the end of the Cold War, documenting the development of nuclear and thermonuclear bombs in the United States and Soviet Union, as well as delving into issues of international politics, espionage, and delivery systems.

Most people are likely to find some aspects of the book tedious, while others are fascinating. For instance, I noted all the descriptions of design details of nuclear and thermonuclear issues with interest, but found a lot of the minute descriptions of espionage activities tedious (especially descriptions of nearly every meeting between the atomic spies and their contacts). That said, the book will certainly offer good rewards to anyone with an interest in some aspect of nuclear weapons or the Cold War.

The last few pages really ought to be read by everyone. They document the shocking behaviour of Curtis LeMay and the Strategic Air Command (SAC) in the period prior to the Cuban Missile Crisis, as well as during it. At the time, LeMay and some of his commanders could use nuclear weapons without presidential authority; they were also obsessed with striking first, and generally convinced that war with Russia was inevitable. Perhaps the most shocking actions detailed are LeMay’s strategy of flying nuclear-capable bombers over targets like Vladivostok, in the Soviet Union. They were running drills and taking photos, but it looked to the Russians exactly like an atomic attack. I don’t think Rhodes is wrong to suggest that, had the Soviets done something similar in America, the SAC would have launched an all-out attack against them. Rhodes marshals compelling evidence that LeMay did, at times, seek to provoke a nuclear war through initiatives like these flights and the provocative American ballistic missile test undertaken during the Cuban Missile Crisis.

The book’s closing also laments the enormous amounts of sacrifice made to build up these massive, threatening stocks of weapons. The Oak Ridge and Hanford complexes, producing fissile materials, used more energy than the Tennessee Valley Authority, Hoover, Grand Coulee, and Bonneville dams could produce together. One year of expanding the facilities required 11% of US nickel production and 34% of the output of stainless steel. All told, Rhodes estimates that the arms race cost America over $4 trillion, which could have otherwise been put to productive uses. On the Soviet side, the story is far more appalling: with thousands of slaves being terrorized and irradiated in the drive to match the American weapons complex. The irony is that, while generals and arms manufacturers clamoured for ever-more warheads, politicians on both sides of the Iron Curtain had already come to understand that the weapons could never be used. Indeed, Rhodes’ account provides a nice counter-argument to the view that all politicians are short-sighted and lacking in wisdom.

All told, Rhodes’ account is an excellent one: historically rigorous, but alive to the human issues raised inevitably by the subject matter. It’s a book that is deeply relevant in a world where US-Russian tensions are growing, weapons are proliferating, and a terrifying number of bombs are still deployed on 15-minute hair-trigger alerts.

The geological plausibility of CCS

Two articles on the April 2nd issue of Nature look into some of the physics, chemistry, and geology associated with carbon capture and storage (CCS) as a possible form of greenhouse gas mitigation. The first largely summarizes the results of the second. Each stresses how significant amounts of carbon dioxide (CO2) are already trapped in groundwater in the subsurface environment, suggesting that the artificial addition of more may be safe and effective. Leaks are avoided due to the “presence of sealing, low-permeability rock formations above the targeted layer,” such as those found above natural gas fields. The article considers CO2-rich natural gas fields in North America, China and Europe as natural analogs for future CCS sites. It concludes that relatively little (about 10%) of the CO2 gets incorporated into rocks, from which it is unlikely to escape. Most remains in water, from which future emissions are more possible. It concludes that the hydrogeological characteristics of future CCS sites will need to be carefully considered, bearing in mind that most of the CO2 will apparently end up saturated in water.

None of this provides definitive support for CCS as a mitigation option. Rather, it provides some guidance into the further research necessary to determine if it can be safe and environmentally effective. Notably, this research also gives no consideration to the economics of CCS deployment, nor to the timelines across which it can be achieved. Indeed, these articles could be taken as evidence of the relative infancy of the scientific consideration of subsurface disposal of carbon dioxide, something that governments assuming its near-term commercial viability should note.

Ocean iron fertilization for geoengineering

The idea behind iron fertilization as a form of geoengineering is this: organisms in the ocean often have a rate of growth that is confined by the availability of a single nutrient. It’s like assembling laptops when there is only a limited amount of silicon around for processors. No matter how many cases, keyboards, and screens you can build, you can’t make finished laptops until you get more silicon. Since iron is often a growth-limiting nutrient in the ocean, the hope is that humans could add it to the sea, causing a bloom in ocean plant life. Those living things would draw carbon dioxide (CO2) from the atmosphere and then, hopefully, sink to the bottom of the sea and keep the carbon trapped there for a long time.

Recently, scientists tried adding six tonnes of iron to the Southern Ocean, around Antarctica. The idea was to test whether such an approach could help draw down the level of CO2 in the atmosphere. As reported by the BBC, the experiment was not very successful. They quote Victor Smetacek as saying:

There’s been hope that one could remove some of the excess carbon dioxide – put it back where it came from, in a sense, because the petroleum we’re burning was originally made by the algae. But our results show this is going to be a small amount, almost negligible.

Basically, the problem seems to be that the algae get eaten by animals near the surface, rather than sinking undigested to the cold ocean floor. That means the carbon remains within the Earth’s physical and biological cycles, rather than sinking down to where it won’t have medium-term effects. It may be that fertilization experiments in other locations, or with other nutrients, prove more successful.

Some odd game theory surrounds geoengineering. One possibility is that no type of geoengineering will not work at all. Another is that it might lower temperatures, but have unacceptable other effects. People also worry that the very possibility of geoengineering makes policy-makers more reckless, since they see it as a possible long-term solution that eliminates the need to reduce emissions. From an environmental standpoint, it would be useful to know that geoengineering certainly would not work, since it would help avoid a dead-end technology and would make it even more clear that emissions must be sharply reduced. That being said, it may be environmentally harmful to learn that it is possible, especially if the harmful consequences will mostly be borne by people living in poor states with relatively low greenhouse gas emissions. Powerful states may be tempted to geoengineer their way out of the climate problem, even if the consequences for those in other parts of the world are appalling. Given how appalling the consequences of our greenhouse gas emissions are likely to be for future generations within our own states, it would not be surprising if voters and governments opt for such a negligent course of action. The fact that we are cheerfully committing suicide suggests that we will probably commit murder without the slightest concern or consideration. Of course, knowing that geoengineering is possible would give us one last desperate option, in the event that abrupt and catastrophic climate change begins.

As it stands, the world simply isn’t coordinated enough to prevent any research into geoengineering. All we can do is fight to ensure the information and techniques that are acquired be used in a responsible way: taking into account the welfare of people around the world, in both this generation and those that will follow.

Crime fighting with DNA ‘family searches’

Over at Slate, there is an interesting and somewhat frightening article about the use of DNA in law enforcement in the United States. As in the UK, the US is now collecting DNA from many people who have been arrested, and retaining the samples even from those never charged or convicted. The next step along this path of DNA surveillance seems to be ‘family searches.’ Here, police look for near matches between crime scene DNA and people in their database. When they find a near match, they investigate that person’s family members.

This is worrisome for many reasons. As the article explains, “courts could well be troubled by the open-ended idea that once you’re arrested and cleared, the state can subject you and future generations of your family members to permanent genetic surveillance.” It is quite shocking really. These days, people are getting arrested for such trivialities as taking photos of major landmarks. The idea that this would then subject their entire family to future police DNA surveillance seems deeply illiberal. The article also makes the point that the DNA kept on file may be re-examined later to test for other traits: for instance, if genes that predispose people to committing rape or murder are discovered. Finally, the article mentions some of the major racial implications of the policy: given the high rates of arrest and incarceration in the African American community, members of that ethnic group are unusually likely to be subject to police surveillance via family searches.

Maintaining a functioning justice system in an era of rapidly changing technologies is a huge challenge. Arguably, search and surveillance are the most worrisome new issues. The automation of both means that huge databases can be maintained tracking emails, cell phone locations, DNA, and much else besides. These databases will inevitably be accidentally leaked and intentionally abused. Just another reason why governments are far more dangerous than terrorists.

Given the popularity of being ‘tough on crime,’ it is easy to see why many people favour a system that sacrifices privacy in exchange to a higher chance of catching criminals. There are certainly arguments on both sides. DNA can help to free the wrongfully convicted, as well as increase the conviction rate for crimes like rape, when the justice system generally does a rotten job of catching perpetrators. Arguably, the fairest system would be to put everyone’s DNA on file. At least that way people would be receiving equal treatment. Of course, that requires putting even more trust and power in the hands of governments and security services that have too often abused it in the past.