Greenhouse gas emissions and statistics

Not surprisingly, I’m confused.

In the run up to the Copenhagen conference, we’ve all learned that the US and China are the world’s two largest emitters of greenhouse gasses. But here’s what’s confuses me:

If you were to do GG emissions per $ of GNP, China would be the most egregious polluter. But if you do GG emissions per person, the US would be the most egregious polluter.

For you climatologists, meteorologists, demographers, and ecologists: are there metrics out there that are intellectually honest comparisons? Or are the economies so different to be literally un-comparable?

(And by the way, I searched “greenhouse gasses” and found no comparable thread.)

I’m not sure what you mean by “intellectually honest comparison.” Not that you’re not asking an honest question, but I don’t know what you’re looking for.

Loosely (very loosely), per capita emissions relate to development and responsibility.

Consider a scenario in which China and India develop to the point at which their per capita emissions are equal to ours – what is already a major looming problem is now several orders of magnitude worse. But how do we tell China that they cannot have two point three cars per family?

Consider a scenario in which reality meets a subset of predictions such that a non-trivial amount of recognizable harm is caused by climate change events. Millions of people are affected by a situation in which for statistical purposes their contribution was negligible, and while nebulous, it is possible to apportion responsibility on a set of countries.

What that responsibility means in practical terms is purely political (and ethical). It could very well come to mean nothing at all. It could mean a dramatic increase in global conflict.

Is this close to what you’re asking?

What I meant by “intellectually honest” is the sort of comparison that seems reasonable when explained, and would be accepted by disinterested people. Its opposite is the sort of comparison that seems reasonable at first glance, but is designed to serve an agenda rather than honestly compare.

Obviously your second scenario would lead to all sorts of comparisons and analyses allocating responsibility among various parties. But we’ll see and hear a lot of it in reporting from Copenhagen, too, and I’m hoping to get some guidance as to how to keep from misunderstanding too much of it.

Easiest measure might be cumulative production to date and projected cumulative by 2050. Problem is I don’t think anyone is going to have that kind of information. Besides, you’d have people coming in and claiming that the re-forestation of NA should be counted against carbon production or that the cumulative impact of the many middle states could be significant when compared to the top 5 producers etc. etc. etc.

China’s emissions per $ of GDP would tend to indicate that their energy infrastructure is inferior and/or their economy is based on a high-energy but lower valued products.

The U.S. has much more capital investment, and relies more on efficiency of production to be competitive. China relies more on cheap labor and has lower capital investments, meaning its factories may be less energy efficient. Less automation, more brute-force methods, more spoilage and waste, etc.

Per capita, America uses more energy because Americans generate much more GDP per capita. No mystery there. This is a pretty bad metric, though. For example, let’s say the entire economy was automated, requiring just one person to push the ‘start’ button. Man, that person’s per-capita energy expenditure is phenomenal!

This is actually a very complex question. For example, if America creates 25% of the world’s wealth, and uses 25% of the world’s energy, is that a bad thing? A lot of the products America makes are exported to other countries, which means the consumption of energy was really the fault of the country that bought the product, but the blame gets put on Americans for having made the product.

Maybe the lesson is that aggregate values like this aren’t of much use, except in the very specific areas in which such statistics are useful measures. And they’re certainly not useful for the purpose of casting moral judgment.

All that matters is the raw number of tonnes emitted. That’s all nature cares about, not how many people or how much GDP it took to emit them. All countries need to commit to reduce their absolute amount of GG emissions, how they do it is up to them (at the moment). But reducing GG per $ of GDP or per capita is simply irrelevant to the task at hand.