Air conditioners all the way down

A well-known scientist (some say it was Bertrand Russell) once gave a public lecture on astronomy. He described how the earth orbits around the
sun and how the sun, in turn, orbits around the centre of a vast collection of stars called our galaxy. 

At the end of the lecture, a little old lady at
the back of the room got up and said: "What you have told us is rubbish.
The world is really a flat plate supported on the back of a giant
tortoise." 

The scientist gave a superior smile before replying, "What is
the tortoise standing on?" 

"You're very clever, young man, very clever,"
said the old lady. "But it's turtles all the way down."

I came across this interesting inaction rationale in the latest Economist analysis of Durban:

Recent work by, among others, Michael Greenstone at the Massachusetts Institute of Technology backs that approach. It shows that hot spells kill few people in air-conditioned America; but in India, where 300m have no access to electricity, the death toll is huge. India’s priority is to provide its people with electricity, and one day air-conditioners. That this will increase its emissions is less a problem for India than for the world. It therefore views any suggestion that it should be bound to curb its emissions as a threat.

Assuming that is indeed a line of argument in India (and the Economist is usually quite reliable) I was interested in how practical this approach might be, so I did some back-of-the-envelope calculations. Readers should feel free to point out obvious errors. Here we go:

There are about 1.2 billion people in India. That number is expected to rise to 1.6 billion by 2050. Let's say we want to protect them from global warming by providing them with central air in their homes and businesses (we could preserve their lives by, say, cooling a single room in their homes and making them all rest and sleep there, but let's assume they don't want to lead that sort of miserable existence.) Let's estimate about 200 million households needed residential air; there will probably be more than that by 2050, but let's be conservative. Some of them may live in cool regions; some already have air conditioning, factoring in to India's current power costs and greenhouse gas emissions, which for the record are:

India (thousands of tons of CO2): 1,742,698

We will also give them 50m commercial systems; they can't spend all day in their houses. We don't need people dropping from heat stroke in the factories, offices, the call centers and the banks.

Using this helpful wikipedia article, I estimated the residential systems would need about 3 tons of refrigeration, while I estimated the commercial systems very conservatively at 10 tons. One ton of refrigeration consumes 3,517 Watts whilst in operation (assuming an seasonal energy efficiency ratio (SEER) of 10). So residential systems consume roughly 10,000W, and commercial systems 35,000W (there is no point in false precision when we are throwing around estimates like this.)

A standard estimate for the use of air conditioning is a thousand hours per year (eight hours a day times a hot season of 125 days). That seems reasonable. That puts us at (10Kw * 1000 hours * 200,000,000 systems) = 2.0 * 10^12 Kw-h for the residential, plus (35Kw * 1000 hours * 50,000,000 systems) = 1.75 * 10^12 Kw-h for the commercial, totaling 3.75 * 10^12 Kwh of electricity required.

So how much is that? Well, at eight cents a Kwh, that power will run you $300 billion dollars a year (20% of India's present-day GDP; even if the economy grew by 300% in short order, they would still be spending 5% of their GDP on air conditioners). But more importantly, at an average emissions density for fossil fuel electricity of 750g (I love wikipedia) that air conditioning generates greenhouse gas emissions of:

India air conditioning alone (thousands of tons of CO2): 2,812,500

That's two and a half times India's current emissions. It's roughly 10% of the total global emissions in 2010. In other words, relative to the 80% emissions cut needed by 2050 to (hopefully) stabilize the climate in the short term, the CO2 emissions of Indian air conditioning would consume half of humanity's global CO2 budget.

The alternative is to keep emitting and keep warming -- and keep building air conditioners, and burning fossil fuels to power them, accelerating the warming further. Eventually we will need to run the air conditions harder, and longer, to deal with warming of +4C, +5C, or even more -- driving the cost and the emissions even higher (while we are also paying to resettle climate refugees, relocate coastal towns, and fight the spread of tropical diseases). Of course, we can't air condition our crops, we can't air condition every home in Africa or South America or the rest of Asia. But other than that, smooth sailing. It's air conditioners all the way down.

Climate change: The Economist gets it

I don't know what it is with The Economist's climate coverage recently, but it's dead on. From a July 31st editorial:

Droughts, floods, deadly storms: the news is full of them. While it's not easy to attribute any individual event to climate change, it is clear that a hotter planet translates into a higher frequency of extreme weather events.

So there you have "the problem of attribution" -- solved. Like cigarettes and cancer, extreme weather is not always cause by global warming. But more warming get you more extreme weather, just as smoking three packs a day gives you a higher risk of cancer. Simple enough?

When we emit carbon into the atmosphere, we impose a tiny cost on society as a whole in the form of more rapid global warming and a greater intensity of the accompanying social ills. Views of the magnitude of this cost differ. Many studies peg it at somewhere between $5 and $150 per tonne of carbon. Other studies indicate that it could be far higher—perhaps more than $1,000 per tonne. But the cost is positive, and a crucial first step to dealing with climate change, therefore, is to charge people for the carbon they emit. If you put a positive price on carbon, this price will be reflected in the cost of transactions, people will internalise the effect of their behaviour on the climate, and emissions will fall.

Why is this so hard for Andy Revkin, Judith Curry et al? The cost is positive. So you internalize the externality. The Economist is a freakn' libertarian journal and has been for a hundred and fifty years. They get it. Where are you?

There's no shortage of crises in the world today, and these troubles collectively reveal the many shortcomings in the institutional arrangements of our modern world. But in some ways, the continuing failure to address climate change in an appropriate fashion is the bigger indictment of government today. The fall-out from an American default would be hugely costly, but it almost certainly wouldn't represent an existential threat to humanity.

Whoa, you're starting to depress me, guys. Can't you give me something hopeful to go away with?

Anyway, it's just about the least surprising political outcome ever, but it's nonetheless noteworthy that in the whole of this major American fiscal debate no one has proposed taxing carbon. Forget the nitpicks; it would be easy to design a tax so that it didn't kick in right away, and so that its impact would be progressive. But people in Washington would literally laugh in your face if you presented a carbon tax as a good policy choice to include in a deficit-reduction package.

Well, that image is going to be stuck in my head for a while. We're in a bad place on the politics, no question. But on the bright side:

1. Politics change -- often quickly, often dramatically. See marriage, gay.
2. Global warming can be relied upon to get worse. And while we should be starting now, or, more accurately, should have started some time ago, as things get later, more people should come around. And late is better than never.