Category: Science

New discoveries, the scientific method, and all matters relating to the scientific study of the physical world

Quantity of solar energy

Advocates of renewable energy often cite the enormous amount of energy passing from the sun to the earth as evidence that their preferred electricity sources can serve all human needs. While feasibility remains an issue, the general claim is unassailable. Indeed, it can be derived from first principles:

  1. We have been merrily burning coal, oil, and natural gas for hundreds of years.
  2. This has produced both heat (which does work and eventually dissipates into the atmosphere) and greenhouse gasses.
  3. The latter increase the share of solar energy that remains trapped in the atmosphere, thus significantly heating the planet.
  4. While local heating can arise from the direct heat of fossil fuel burning, this is not a significant planetary phenomenon.
  5. Thus, the extra solar energy being retained by the planet because of greenhouse gasses is much greater than the amount of energy being added to the planet by the burning of fossil fuels and the fission of uranium.
  6. As such, the total energy incoming from the sun must be much greater than the total energy being produced through fossil fuel burning.

Of course, the energy in fossil fuels also came from the sun in the first place – back before the organic matter that comprises them got buried underground and chemically altered through heat and pressure.

To make things a bit numerical, consider this. The total amount of incoming solar energy at any point in time is about 174 petawatts (10^15 watts). That is 1.524 zettawatt (10^21 watt)-hours per year of energy. In comparison, global electricity production from thermal sources is about 11.4 petawatt-hours. That is 130,000 times less than the quantity of solar energy, despite the fact that we are burning far more fossil fuels each year than are formed during that span of time.

International emissions trading

In many quarters, there is considerable resistance to the idea of international carbon trading. Some people characterize it as shipping money abroad for no reason, or the buying of ‘Hot Air.’ While there have certainly been problems with the implementation of carbon trading so far, the principle is intellectually sound. It could serve as a strong mechanism for reducing the total costs of climate change mitigation.

To understand why, consider that the major purpose of international carbon trading is to make tonnes of greenhouse gas emission reductions into a commodity. As such, their economic characteristics would be akin to those of other internationally traded commodities. Consider, for instance, an island state that requires copper for various purposes. It is technically possible to acquire copper on their territory, but the costs of doing so are enormous. Their copper reserves are dispersed and of poor quality, making the cost per tonne of finished copper excessive. Provided that the cost of buying copper internationally is lower than that of producing it domestically, the sensible thing to do is to buy the stuff on the world market. If the situation changes somehow (international prices rise, or foreign prices fall), the economically optimal choice may change as well. In the case of copper, this is immediately clear to virtually everyone. States that can produce copper more cheaply relative to other things sell copper internationally while those in the converse situation buy it. Both states with low-cost and those with high-cost copper benefit from this arrangement.

When it comes to carbon emissions, there are still comparative advantages that differ between states. This creates the possibility of positive sum trade: an exchange where both sides end up happier than they would be without trading. A relatively wealthy state that has already eliminated all the greenhouse gas emissions that can be easily forgone can pay a developing state to cut their own emissions. The buying state spends less than they would for producing the reduction domestically, and the receiving state gets the economic incentive to mitigate.

To reach this point, a few critical things are needed. First, for emission reductions to be tradable as a commodity, they must be measurable and verifiable. They differ from other commodities in that it is much more challenging to measure the tonne of CO2 a factory does not produce than the tonne of carbon that it does. That said, the difficulty is surmountable. We know how much greenhouse gas is produced by using different fuels in different ways. We also know how much is produced through different kinds of industrial production, such as cement manufacture. All that is required is the infrastructure and personnel to quantify and ensure reductions.

A trickier problem is that of additionality. If Country X pays Country Y $Z to build a natural gas power plant that will produce ten million fewer tonnes of CO2 than a coal power plant, it can only legitimately bank those tonnes if it was only the payment that motivated the choice. If Country Y actually chose the gas plant because coal plants pollute terribly and coal prices have been rising, Country X did not produce as many ‘additional’ reductions as intended. As with simple measurement, additionality is a practical problem that can be addressed through scientific and economic tools.

Developing and deploying those kinds of tools, so as to further the emergence of a robust and effective international carbon market, should be an excellent way to cut total human greenhouse gas emissions in a relatively rapid and low-cost way.

Climate change impacts, ranking severity

These are summer days and the blogging is slow. In the spirit of audience participation, here is a quick poll.

Which three of the following climate change impacts do you expect to be the most severe? Please answer first for 2050 and again for 2100. You can interpret ‘severity’ however you like: economic cost, number of deaths, total damage to ecosystems, etc.

  1. Sea level rise
  2. Droughts and floods
  3. Extreme weather events
  4. Ocean acidification
  5. Ecosystem changes (such as invasive species)
  6. Effects on pathogens (such as malaria)
  7. Agricultural impacts
  8. Impacts on fresh water quantity and quality
  9. Other (please specify)

Clearly, there is some overlap between the options. There are also second-order effects to be considered, like the impact of agricultural changes on inter- and intra-state conflict.

Portable artificial kidneys

As dialysis equipment demonstrates, the kidney may be the first vital organ that humanity manages to replicate with a good deal of success. That is especially true if prototype portable equipment proves effective. The present iteration of the ‘automated, wearable artificial kidney’ looks fairly bulky and inconvenient, but it is not inconceivable that implantable artificial replacement kidneys may eventually be possible.

Virophage discovery

A while ago, I mentioned a virus that infects a fungus and in turn allows a grass to live in hot soils. Recently, scientists discovered a 21-gene virus that infects larger viruses. The virus, called ‘Sputnik,’ infects a larger virus which in turn infects amoebas.

It just goes to show how complex the lives of microscopic organisms are. It also adds additional fuel to the debate about whether viruses themselves are actually alive, or whether they can only be considered alive after they have been incorporated into the nucleus of a host cell.

The media and climate change ‘dissent’

This Ron Rosenbaum article in Slate argues that it is inappropriate for journalists to portray “the anthropogenic theory of global warming” as an undisputed fact. It cites the importance of considering dissenting views, and asserts that the history of science shows that a consensus held by most of the scientific community can be wrong. While there is some value to both arguments, I think they are weaker than the counter-arguments, in this case.

Starting with dissent, we need to appreciate the character of the consensus on climate change and the character of opposition to it. As discussed here before, there are areas of greater and lesser certainty, when it comes to climate change. What is absolutely certain is that we are increasing the concentration of greenhouse gasses in the atmosphere and that, in turn, causes more energy from the sun to be absorbed. The precise consequences of that overall warming are not known with certainty, but we do know enough to have very good reason to be worried. Arguably, those dissenting from this view are a combination of the self-interested (industrial groups reliant upon heavy emissions, conservative ideologues opposed to government regulation) and conspiracy theorists. The doubts of legitimate scientists establish the areas of uncertainty within climatic science, including questions about the strength of feedback mechanisms, the effects of planetary warming on regional weather, and so forth.

On the matter of scientific consensus, the article argues that a “lone dissenting voice of that crazy guy in the Swiss patent office” overthrew the Newtonian conception of gravity. This is a relatively absurd claim. Firstly, relativistic physics essentially includes Newtonian physics as a special case, in situations where velocities are not close to the speed of light and massive objects are not close at hand. Secondly, the process through which Relativity became an established scientific theory was largely focused on the collection of empirical evidence (demonstrations of gravitational lensing, for instance) and the refinement of the theory within the scientific community. Newtonian physics, for its part, is still completely adequate for planning space voyages within our solar system – the basic relationships posited within it are close to correct in most cases. If we have done so well with our climate models, we have engineered them effectively indeed.

Relations between science and the media will always be challenging. The media generally doesn’t have the time, expertise, or interest to deal with nuance. It also lacks an audience interested in cautious and non-confrontational assessments of fact. In short, the kind of story that is demanded of the media is one in which the scientific process and the character of scientific conclusions cannot always be presented effectively. Moderating some of the incentives to distort that are inherent to the contemporary practice of journalism is thus an undertaking with some merit. It is not as though we should forbid any mention of opposition to our general understanding of climate change; rather, journalists should strive to make clear that the evidence on one side is overwhelmingly stronger than that on the other. A defendant who was seen to stab someone in the middle of the field at the Super Bowl, viewed by millions of people, surely has the right to make a defence at his trial. He does not have the right to media coverage that gives equal weight to claims that he had nothing to do with the death.

Temperature and extreme weather

A new article in Science provides observational evidence of the link between rising temperatures and extreme weather events:

These observations reveal a distinct link between rainfall extremes and temperature, with heavy rain events increasing during warm periods and decreasing during cold periods. Furthermore, the observed amplification of rainfall extremes is found to be larger than predicted by models, implying that projections of future changes in rainfall extremes due to anthropogenic global warming may be underestimated.

Of all the impacts of climate change, extreme weather seems especially likely to help spur mitigation action, especially when that weather occurs in rich states. Reasons for that include the visibility and newsworthiness of floods, droughts, hurricanes, and so forth. Another major factor is the importance of the insurance industry, especially insofar as their professional estimations of risk affect the cost and feasibility of different projects. That is, so long as policy-makers do not establish incentives for risky behaviour.

Nanomaterial safety

When it comes to geological periods of time, our intuitions about how things work cannot be trusted. This is a reflection of the parochial character of many of the heuristic shortcuts in our minds. The same thing applies to the behaviour of objects at a minute scale. For instance, sufficiently tiny machinery is hampered enormously more by friction and surface tension than a larger equivalent would be. Because they have more surface area relative to their volume, they also tend to be much more reactive.

Indeed, asymmetries of behaviour at different scale raise serious concerns about the safety of newly developed nanotechnologies. Just as our brains are calibrated to deal with the kind of experiences that have been normal to human lives for thousands of years, our regulatory procedures are calibrated to respond to known risks like toxicity or corrosiveness.

There have certainly been serious problems that arose from regulation lagging innovation in the past. Think of ozone-destroying chlorofluorocarbons, or mesotheliomas caused by chrysotile asbestos. Balancing safety concerns with the desire not to stifle innovation is extremely challenging, especially when the entities with the most sophistication in relation to a new technology are its commercial backers.

In some cases, nanomaterials have almost completely escaped regulation because it has been assumed they behave like their non-nanoscale equivalents. That said, nanoscale titanium dioxide is not the same as a macroscopic bar of the stuff. The same is true for carbon nanotubes, silver nanoparticles, and so forth. Indeed, if the substances were equivalent, there would be no promise in nanotechnology itself. Especially when it comes to the exposure of nanoparticles to human beings (though food, cosmetics, etc), it makes sense for the nano-versions to be regulated as new substances, with the onus on the manufacturers to demonstrate safety.