Category: Science

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

Defining science

The other day, Tristan and I were trying to ‘science’ and it became evident that the term has a stack of meanings. Those at the top arguably have the most day-to-day relevance, whereas those at the bottom are arguably more fundamental to the nature of science:

  • At the highest level, science consists of the people and institutions generally considered to be undertaking scientific work. This includes today’s physicists, chemists, biologists, and so forth. In an earlier era, it would have included alchemists. It also includes universities, research centres, funding bodies, and the like.
  • At the next level, science consists of a collection of theories that explain aspects of the world. Contemporary examples include special relativity, quantum mechanics, and the germ theory of disease. Kuhn’s Structure of Scientific Revolutions is an enlightening text largely about how these emerge and change.
  • At the next level, science is a set of key beliefs. Basically, these are that the universe operates in a manner that is consistent and comprehensible. In addition, it is at least theoretically possible to come to understand its workings through observation – using the mechanism of formulating and evaluating hypotheses.

The first two are very much affected by general trends in society and thought. The third is essentially assumed in the way through which our minds access the world. While we certainly cannot always understand the causal relationships involved (and random chance may always play a role that makes complete solution impossible), our mode of thinking fundamentally requires the assumption that things cause other things according to certain rules and that in the same conditions the same rules hold. We may never be able to track the course a hurricane will follow (or the hallucination a brain will have) on the basis of what atoms were where beforehand and what laws apply to them. Even so, a basic assumption of science is that such things are theoretically knowable, within the limitations created by random chance.

When it comes to the universe as a whole. it is quite possible that the collection of governing laws exceeds the human capacity to understand and/or discover. That becomes especially plausible if we accept the possibility that ours is just one of several universes, or that it is itself embedded in something far more complex.

Previous posts about the philosophy of science:

Debating the future of energy

The Economist is holding a debate in the style of the Oxford Union debating society (which I never joined while there due to the excessive cost). The topic is: “We can solve our energy problems with existing technologies today, without the need for breakthrough innovations.” This certainly seems to be the emerging wisdom among those who have looked seriously and comprehensively at the problems of energy and climate change. That’s not to say that technological improvements in things like batteries and photovoltaic cells would be useful, it is simply to assert that ‘breakthrough’ new technologies are not required, though they may well help.

The debate should be an interesting one to observe. The opening statements are from Joseph Romm – whose book I discussed earlier – and Peter Meisen.

Climate change, deforestation, and the deep sea

A while ago, there was an excellent question posted as a comment. The Stern Review and other sources say that the world can absorb about five billion tonnes of carbon dioxide equivalent per year. If emissions are above that, atmospheric concentrations rise. If they are below that, they fall. Does that mean that, in the absence of human activity, concentrations would be falling, year-on-year? Are our first five gigatonnes of emissions stabilizing?

To answer this, you need to remember that there are two big kinds of carbon sinks out there. The first is embodied in forests, but consists of all biomass. A world where all the forests of North America and Europe were intact would have less carbon dioxide in the air because more would be in wood, leaves, etc. That being said, for any level of forest cover and atmospheric greenhouse gas, the biosphere will eventually reach an equilibrium point where it emits as much carbon dioxide (from decaying plants, etc) as it absorbs from the air. The biosphere is thus more like a cushion than like an eternal allowance.

The other kind of sink consists primarily of the deep sea. It’s like a great big sponge that absorbs carbon dioxide. At present, it can absorb about five billion tonnes of carbon dioxide equivalent per year (the source of the Stern number). Like a sponge, however, it can only carry on absorbing for some time. As the deep sea becomes saturated with carbon dioxide, a higher and higher proportion of what we emit will remain in the atmosphere causing climate change.

In the long run, then, we don’t have a perpetual allowance of five gigatonnes per year. We have some big sinks that can absorb about that much at present. We need to rapidly cut human emissions below this level. Then, over a longer period of time, we will need to phase them down to virtually nothing. Otherwise, we will always have to contend with rising atmospheric concentrations of greenhouse gasses and the environmental consequences thereof.

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.