CO2 & Your Car

French cities seem on the verge of banning SUVs to improve pollution. But is banning 4WDs really such a hot strategy to reduce CO2 in the world’s big cities? Where do passenger vehicles really fit in when it comes to greenhouse?

The big French cities say they’re in the process of banning gas-guzzling vehicles – including 4WDs – in an attempt to curb emissions.

The exact scheme to be put in place – exactly which vehicles, in exactly which neighbourhoods, and exactly what penalties could be enacted – are at this stage still unstated. But the intent to proceed with the project has been firmly declared.

Denis Baupin, an environment official in the Paris mayor’s office, said that the city would soon test restrictions targeting 4WDs and old diesel cars. Mr Baupin said any Parisian driving one should, quote: “Sell it and buy a vehicle that’s compatible with city life.” Mr Baupin added, quote: “I’m sorry, but having a sport utility vehicle in a city makes no sense.”

Maybe he hasn’t noticed, but our cities seem to be knee-deep in them. SUV sales in Australia are one of the strongest growth segments.

Is Mr Baupin right? Does putting a 4WD in a big city make no sense? Should 4WDs and older vehicles be banned in the quest for cleaner air? Or do these kinds of suggestions merely provide slick-sounding sound bites when the cameras are rolling?

Here in Australia we’re amazingly urbanized for such a big country. In 2007, according to Ausstats, our 11.5 million passenger vehicles drove an average of just 13,700 kilometres each, annually.

Let’s say you own an SV6 Commodore – one of Australia’s most popular cars. (If you’re our growing band of North American listeners, a Commodore is approximately a Pontiac G8 – albeit with the steering wheel on the ‘wrong’ side.) This kind of car weighs about 1800kg. It’s got respectable outputs - 210kW and 350Nm. On the CO2 front it emits 234 grams for each kilometer you drive, according to the Federal Government Green Vehicle Guide.

In three years of average motoring an SV6 Commodore will emit 9.6 tonnes of CO2.

If you buy a very different vehicle, say a BMW X3 with the 3.0-litre diesel engine, you get a machine weighing about 1800kg – same as the Commodore. It offers 160kW peak power, which is 50 down on the Commodore. But it ups the ante on torque, with a massive 500Nm – that’s 50 per cent more than the Commodore, in round figures. And it emits 206 grams of CO2 for every kilometer driven – a significant step forward for clearing the air – with a reduction of around 12 per cent CO2, compared with the Commodore.

In three years of average motoring, the BMW SUV will emit more than one tonne less CO2.

In fact, to buy a conventional petrol-powered car that’s line-ball on CO2 with an advanced diesel 4WD like the X3, you need to ditch the Commodore and downsize to something like a Mitsubishi Lancer VR-X manual, which, according to the Green Vehicle Guide, emits 207 grams per kilometer of CO2.

I don’t know what you think of the French concept of demonizing particular classes of vehicles. But I think what’s required here is actually very simple.

Fuel consumption is basically proportional to CO2. If you burn one litre of petrol you emit 2.4 kilos of CO2; one litre of diesel becomes 2.7 kilos of CO2. That’s intrinsic to the nature of combustion and basically impossible for engineers to subvert using clever technology.

It means demonizing 4WDs on the basis of their emissions is bureaucratic BS, however much you might hate having them in your city. If you want to reduce pollution, you need to do two things:

First, you need to make the fleet of cars on the road more modern – because the current technology will always be the cleanest. You achieve that with the carrot and the stick: by offering financial incentives to buy a new car (such as cheaper registration and other statutory charges). And you add disincentives for owning older cars (such as increased registration charges).

More importantly, to reduce emissions, governments need to go straight to the source of the problem and put higher taxes on it. Once fuel becomes more expensive, consumers will increasingly opt for more fuel efficient transportation, and emissions will drop. Except for the rich. They’ll drive whatever they want … but then, they already do.

Cutting CO2 seems like a good idea in principle, but I’m not a climate scientist, and you probably aren’t either. Most people aren’t. If the balanced view of credible scientists is that we need to cut CO2 emissions, fair enough – let’s do that. Even if it does the climate no good, ultimately, it will reduce national dependency on foreign oil – and that’s a good thing.

But let’s reduce CO2 in a rational way, by targeting the biggest emitters, effectively picking the lowest-hanging fruit first. That seems like a reasonable way to go about it.

It begs an obvious question: What exactly are the big CO2 emitters?

The Federal Government’s Department of Climate Change and Energy Efficiency (what a mouthful) publishes a National Greenhouse Gas Inventory, which you can download as a PDF. Having trouble sleeping? It might just be the cure. It lists all the big CO2 emitters. It’s very interesting reading if you’re a car enthusiast (or if you’re a cow – we’ll get to that).

According to the official National Greenhouse Inventory, the country’s total CO2 emissions for the year to December 2009 were 537 million tones (Mt) of something called “CO2-equivalent”.

They use the term ‘CO2-equivalent’ because, basically, there’s more than one greenhouse gas. There’s CO2, oxides of nitrogen, methane (which is natural gas), and halocarbons (which are common refrigerants). All these gasses don’t contribute equally to the problem, so the actuaries convert them to equivalent amounts of CO2 in terms of their greenhouse contribution, for fairness. All the figures quoted in this report are in million tones of CO2 equivalent.

So, recapping, Australia’s total annual emission is 537 million tonnes.

Here’s bombshell number one: of that national total, passenger cars emitted just 42Mt – or less than eight per cent of the total.

Electricity, on the other hand, once touted as a purportedly clean form of energy, delivers a mind bending 202Mt, or 38 per cent. So electricity, which we mostly derive from burning coal, emits five times the greenhouse gas of the humble passenger car. It really makes you wonder if you’ve got any unnecessary lights burning in the house…

Agriculture, which you might otherwise consider to be a relatively green vocation, emits a staggering 84Mt of greenhouse gas – that’s exactly double the greenhouse contribution of the passenger car.

This next bit is somewhat indelicate: When you dive down into agriculture’s 84Mt contribution to the problem, 56Mt is the product of the ‘enteric fermentation’ of livestock. These are official government data. Enteric fermentation is a very esoteric and technocratic term for millions of cows and sheep farting methane gas as a consequence of digesting grass. It’s not a joke … but it is something of a new take on the term ‘exhaust emissions’. It means cows and sheep farting (or, if you prefer, ‘enterically fermentating…’) is a bigger greenhouse issue than all of Australia’s passenger cars put together.

Fuel consumption in the mining of non-energy resources (things like iron ore, bauxite, gold, lime, etc.) is a 49Mt greenhouse issue – that’s 17 per cent more than passenger cars. So exploiting our national mineral resources is a significantly bigger greenhouse issue than driving our nation’s passenger cars.

Industrial processes – like refining minerals or producing cement – plus emissions from the chemicals industry, and metal production (like making aluminium from bauxite) – account for 31Mt worth of emissions. So-called ‘fugitive emissions’ – which are gasses that escape from the production of coal, gas, oil and solid fuels – total 40Mt. And, of those, 29Mt comes from coal mining and decommissioned coal mines.

Basically, industries that simply haven’t learned how to control their leakages is almost twice as big a greenhouse problem as driving passenger cars.

How about deforestation? Monty Python sang the famous song about being a lumberjack, and that being okay, but cutting trees down releases 50Mt worth of annual greenhouse emissions, although this is somewhat offset by reforestation schemes, which sequester carbon and bring that total down to a more respectable 23Mt – call it a little over half the total of passenger car emissions.

When you boil this all down, preferably using clean, renewable energy, you’d have to conclude there’s something of a gap between the public perception of the greenhouse problem, and the facts. If you say ‘climate change’ or ‘CO2’ or ‘greenhouse problem’ to your average Joe in the street, in general conversation, nine times out of 10 the car will be fingered as being a principal culprit. I wonder where these people think the electricity for their air conditioners and 42-inch plasma TVs comes from?

We’re never going to make a real dent in CO2 by demonizing the car. Or by reducing the fuel consumption of passenger cars without targeting the even bigger emitters in a similar fashion.

If we could cut the fuel consumption of passenger cars by 15 per cent overnight (and we could do that, theoretically, just by driving a bit smarter) it would make just over one per cent difference to the national greenhouse emissions picture.

However, if we did the same thing with electricity and cut consumption by 15 per cent (also possible in theory) it would make almost six per cent difference to national greenhouse emissions. Same percentage change; six times the result. By targeting a bigger problem sector.

Frankly, you’d be doing the greenhouse problem a bigger favour by using less heat in winter, less air conditioning in summer and turning off the lights when you’re not in the room, than you would by ditching a somewhat large car you might love driving even if doing so has been making you feel increasingly the environmental vandal, lately.

The car is simply not the only hurdle on the road to preventing envirogeddon. It’s certainly not the biggest hurdle, either, and the car industry has lately done much more than some, like mining, to clean up its act.

It’s convenient rhetoric in some circles to point the finger at cars and call them environmentally evil devices, but doing so is actually way off target. It won’t cut CO2 enough – but it will get the environment lobby groups on the TV.