Sunday, 4 December 2011

In Favour of Marriage Equality

Same-sex marriage is an issue on which reasonable people can disagree.
It's a mistake to automatically label opponents of same-sex marriage as homophobic bigots. It's just as cringe-inducing to hear proponents of marriage equality described as anti-family radical activists. Experience tells me that both sides of the discussion are populated with normal, well-adjusted people, trying to make reasonable decisions based upon the best information available to them.

I expect that you, dear reader, are such a person. Regardless of where you stand on the issue of marriage equality, I imagine that we share the same basic moral values and concerns. Hopefully that means we can have an amicable discussion, and that we're able to thoughtfully consider alternative views, and be willing to reformulate our opinions when logic and evidence requires us to do so.

I'm a supporter of marriage equality. I claim no special expertise or authority on the subject, but do consider myself reasonable and well-informed. The arguments in favour of same-sex marriage seem to me to be stronger and better supported than those against it. Of the latter, there are a few objections that I hear quite often, and would like to briefly address here.

Bad Objection #1 - Marriage has an important historical definition and we shouldn't change it.
History alone is not a good justification for law. Less than 50 years ago, the US repealed it's anti-miscegenation laws and redefined marriage to include interracial couples. This went against centuries of established tradition, and most would agree that the world is a better place for it.

The concept of marriage is neither narrow nor uniform. It can signify a social contract, a religious ordinance, a political arrangement, a historical tradition, an economic expediency and much else besides. It is frequently claimed that marriage is primarily a way of recognising the procreative potential of a man and woman, and that might be true. This does not, however, lead us to deny marriage to couples who are infertile, elderly, or choose not to have children.

As a society, we recognise that child-rearing is just one of the many reasons that a couple may choose to get married. For a lot of people, marriage is primarily a public declaration of a couple's mutual love and commitment to remain with each other. The legal status of a relationship is not tied to its ability to produce children.

Removing discrimination from marriage laws and making them more inclusive in the past did not destroy the institution's value, and it is hard to imagine why it would do so now.

Bad Objection #2 - Same-sex marriage runs counter to moral convictions of many people.
Most of us place great value on our individual freedom to think, speak, and act as we choose. While we willingly submit ourselves to restrictions that prevent us from doing harm, very few people regard the Government as having any further role in defining what ideas and behaviours are good or bad. The legal status of same-sex marriage is therefore not a commentary on its desirability or appropriateness, just its lack of harm.

Unless we have good reason to suppose that same sex marriage would cause harm to other people, we have no justifiable basis for preventing it under the law. Moral instruction is the responsibility of families and communities, not governments.

Bad Objection #3 - Marriage equality will have a harmful effect on freedom of speech and religion.
I know many people who believe that marriage equality will lead to churches being forced to keep silent about homosexuality, or be legally required to perform wedding ceremonies for same-sex couples. This is simply untrue. Section 116 of the Australian Constitution safeguards the free exercise of religion and the attendant rights of expression. The rights of private religious organisations in this country would be unaffected by changes to the scope of the legal definition of marriage.

The best way to protect churches is to commit more fully to the principles of free thought, speech and action. If anything, marriage equality serves to reinforce those freedoms, not threaten them.

A parting thought...
I said at the start that there are reasonable people on both sides of this debate. I really believe that. There are also a lot of people who simply aren't that interested in the subject, or haven't thought about it very deeply, or regard it as a trivial annoyance. This is an issue, however, that directly affects the lives of real people. It's much more than an academic debate, so whatever stance you take on this, make sure that your reasons are good.

If you oppose marriage equality, and one or more of the objections above were part of your justification, I hope I've given you pause to think. I'd love to hear your thoughts in the comments.

Saturday, 6 August 2011

CO2: Friend or Foe?

There’s a presentation entitled “A Cool Look at Global Warming” currently doing the rounds on the internet. It’s nothing new or unusual as far as the anti-science stuff goes (i.e. it’s mostly garbage), but it does repeat a few odd claims that I see pop up frequently in the Climate Change debate. They’re claims about the nature of Carbon Dioxide, and you’ve probably seen them before:
  1. CO2 is only a trace gas in the Earth’s atmosphere (0.039% by volume).
  2. CO2 is naturally occurring.
  3. It’s odourless and non-toxic.
  4. It’s invisible to human eyes.
  5. It’s necessary for photosynthesis.
  6. Carbon is one of the most important elements on the planet.
  7. Humans contribute only 3% of atmospheric CO2 emissions.
  8. The oceans contain 50 times more CO2 than the atmosphere.

Now, when I say these claims are odd, I don’t mean that they’re untrue. They’re all perfectly correct. However, with the exception of #4, they’re also all perfectly irrelevant in a discussion of climate change. Here are a couple of important CO2 facts, ones that actually matter to the debate, that didn’t make it into the presentation:

  • CO2 strongly absorbs infra-red light.
  • CO2 does not condense and precipitate out of the atmosphere under current conditions.
  • Human activity is the direct, primary cause of a 39% increase in CO2 from the pre-industrial era.

That’s it. Those things are what make carbon dioxide important. The relative volume in the atmosphere doesn’t really matter, because the other gases don’t interact with I-F light the same way. The fact that it’s invisible to human eyes means that it’s transmitting visible light. By allowing visible light to pass, but absorbing infrared, CO2 acts as a kind of one-way insulation. It may be a trace gas, but it (along with the other greenhouse gases) significantly retards the rate at which the planet radiates heat back into space.

With no greenhouse gases, the average global surface temperature would be -18°C, and all our bits would freeze and drop off. So, yay for CO2, right? All of those positive claims about it are correct. But, if solar irradiance stays the same, and CO2 goes up further, then the radiative equilibrium temperature of the planet goes up too. This is the main reason why Venus is the hottest planet in the solar system, despite lower insolation than Mercury.

Now, humans may contribute only 3% of CO2 emissions, but nearly all of that comes from carbon sources that were locked away over millions of years in fossil fuels. The other 97% is part of a fairly stable cycle of natural emission and absorption. What humans put into the atmosphere has no corresponding sink, and we’re consequently responsible for most of the 39% increase from pre-industrial levels. We’ve pulled that off in an unprecedentedly short time scale.

This is why industrial CO2 emission is pollution, even though CO2 itself ordinarily isn’t. The former has the potential to alter the climate in detrimental ways, doesn’t go away very easily, and needs to be controlled. This doesn’t mean the Sun isn’t an important factor, or that CO2 wasn’t higher in earlier periods of geologic time (it sometimes was). It just means that right now, we’re fiddling with an important and well-documented control knob for global climate, and we need to be very careful about it.

CO2, like the heat it traps, is a very good and necessary thing. Too much of it though, and you’ve got trouble. It sucks, but there you go: