I’ve just come back from a holiday in South Africa, and it occurs to me that flying there and back blows my other transport-related emissions for the year out of the water. My partner and I use around 1,000 litres of petrol a year between us, travelling 10,000 km or so. Our CO2-equivalent emissions from this driving are around 2.3 tonnes. On this holiday, though, the return distance is about 28,000 km, or 56,000 km between the two of us (I’m assuming all the flights are in a straight line, to keep things simple). That’s a pretty long way to travel – almost one and a half times around the planet, and probably one of the longest trips you could make from New Zealand, although not that much further than going to Europe.

Long-distance air travel burns a lot of fuel. As a rule of thumb, the level of emissions from this fuel combustion is about the same as a single-occupant car, per passenger kilometre. Aeroplanes are usually at least 60%-70% full, of course, compared to a 20% full car, but it takes rather more energy to sling people through the sky at 900 kilometres an hour. My flights were with Qantas, and – good on them – they’ve got an emissions calculator and ask you if you want to offset your emissions. Here’s the results I got, which seem reasonable.

Qantas emissions results

In total, the calculator tells me that the flights created just over 4 tonnes of emissions per person, which you can then offset at a cost of less than AUD $10/tonne (reflecting low market prices for emissions in the schemes where they are traded, which may not be a true picture of their impact). I didn’t pay the offset – I’m wary of tokenism – but that’s not really what this post is about. I’m wanting to highlight a couple of other issues.

Firstly, the Qantas calculator, like most other ones you might be able to find, is based mainly on the direct emissions from fuel combustion. However, total flight emissions can be quite a lot larger than this. Air travel makes a big contribution to climate change through high-altitude emissions of water vapour, nitrous oxides and other gases which are believed to have a greater impact than they would at ground level. Most (all?) emissions tax/ trading regimes don’t take this into account at the moment, because there’s still a bit of debate around the size of the effect. Presumably this will change at some point, as the science becomes more precise. For now, I’d just note that the estimates you’ll get from these calculators should be considered very much at the low end.

Secondly, long-distance air travel is an amazing thing. You can now get to the other side of the world in less than 24 hours, even with a stopover or two along the way. This has made all sorts of new trips possible, and air travel has grown at an astonishing rate over the last 50 years or so. The lack of substitutes for this rapid, long-range travel makes it all the more important that some solutions are found to the problem of its emissions. Progress is being made – see this post, and I’ll write soon about the potential for biofuels to be used in aviation – but there’s a very long way to go. Realistically, it’s going to be much easier for the world to cut emissions in other areas, rather than aviation.

Thirdly, countries like New Zealand should be very aware of this kind of thing; tourism is a big earner for our economy, and many of those tourists come from distant markets like Europe or America. Greater awareness of climate change issues could affect long-haul travel. South Africa’s in a similar position, if not as remote as NZ – there was a quote I read somewhere which said that, given the problems they have with animal poaching, the only way South Africans would respect and value their wildlife and wilderness areas sufficiently would be if they could build a sustainable eco-tourism economy out of them. As for outbound tourism from NZ, i.e. Kiwis travelling overseas, the reality is that we do a lot of it, and it’s a big part of our lifestyle. I’d argue that this creates a need to focus more on emissions here at home, if we want to keep enjoying the benefits of overseas travel. There are plenty of people who, like me, actually create most of their emissions when going on holiday rather than through what they do at home.

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22 comments

  1. As far as carbon dioxide emissions go, a plane emits less than a vehicle being driven the same distance. The major issue is that it enables vast distances, well beyond what was possible before jet air travel. We’ll have this problem for a while as there is nothing with the energy density of av-gas, and improvements are incidental on what are now very well optimised aircraft. We’ll need radically different technologies before flight becomes low or zero emissions.

    Aircraft are improving in efficiency by about 20% per decade. However, air travel is growing at a much greater rate, coming off a very low base in newly middle/lower-middle income countries (China, Indonesia etc.)

    High speed rail is a potentially lower-carbon alternative in many cases, but it isn’t problem free from either an environmental or practical standpoint.

  2. I think the Sydney – Johannesburg maybe incorrect. Sydney – Perth, and then Perth – Johannesburg only comes to 1375kg rather than the 2118 for Syd-JBurg direct on their calc.

    1. Yeah, there seem to be some bugs in the calculator. You also get some very different results if you enter Sydney -> Durban.

  3. Planes typically fly at 80-90% full these days: eg for the March quater Air NZ says “Group load factor was 83.8%, down 2.0 percentage points.”

    From memory, you need about 3 people int he car going from Auckland to Wellington to reduce carbon output (though some arguments suggest carbon at higher altitudes are worse…).

    1. Air New Zealand runs a pretty tight ship, and manage high load factors compared with other airlines… typically, the planes on long-haul routes won’t be that full. I think.

      1. Air New Zealand domestic is around 85-86%, which is pretty high and one reason they’re turning a good profit. On international they’re in the low 80s.

        I wonder how we could get higher load factors on other forms of transport without impacting (cutting) quality of service.

      2. From wikipedia: According to the International Air Transport Association, the worldwide load factor for the passenger airline industry during 2013 was 79.5%.

    1. That article has a few basic errors:

      “It was not until the turn of the century, though, that high-speed maglev would come into commercial operation, mostly in Japan and China.”
      The 30.5km line to Shanghai Pudong airport is the only “commercial” maglev, all others are test facilities.

      “Magnetic levitation trains, or maglev for short, have been a big hit in Asia thanks to their incredible speed and capacity.”
      Not so much. When it opened in 2004, the Shanghai maglev only ran at 20% capacity. By 2007 after reducing prices it managed to return its cost of operation, but none of the US$1.33B capital cost. Plans to extend the line ~200km to Hongqiao airport and to Hangzhou were aborted. Ordinary HSR was constructed to Pudong airport in parallel.

      “The world’s fastest passenger-carrying train is currently the Shanghai Maglev Train, opened in April 2004, which can reach 268 miles (431 kilometres) per hour.”
      Depending on wind, it can run to 433km/hr but outside of 9-10:45am and 3-3:45pm top speed is now limited to only 301km/hr. Very disappointing so take care when booking flights.

      “Aerodynamic noise will break through 90 decibels (the environmental standard is 75 decibels).”
      Suitable insulation solved that problem in aeroplanes, think 120dbA+ outside on takeoff.

  4. The more sophisticated calculator at Atmosfair.de gives 9.4t per person, broken into 3.2t CO2 and 6.2 ozone, contrails, etc. They will also charge you EUR217 to compensate, which is well over $10/t.

    Start at https://www.atmosfair.de/en/kompensieren/flug?departure=AKL&arrival=JNB, then add your stopover in Sydney. You can specify the plane type if you remember. There is no dropdown for airline, but they have just released a detailed index of airline efficiency which ranks Air NZ 64th. There are 100 pages about the methodology if you’re really interested. https://www.atmosfair.de/en/73

  5. The deposition of water and soot particles from jet exhaust at altitude makes contrails (=clouds).

    Clouds reflect heat during the day but are even more effective as insulation at night.

    Contrails eventually evaporate/disperse. How fast depends on a multitude of factors but usually several hours.

    Flying during the morning must have a lower impact on global warming than flying at night..

  6. I did hear that China’s extremely efficient High Speed Rail services is hurting the airline industry, which is currently having huge issues with delays due to overcrowding and restricted air spaces.

    1. I’ve heard that the same effect on short-haul air routes has been observed in Europe now that the continent has a multitude of very high speed rail lines.

      (It’s also possible that rail is taking travellers from the airlines because trains, so far, do not require the security theatre inflicted on long suffering air passengers.)

      1. Different modes are suitable for different stage lengths. Europe’s population distribution supports high speed rail very well. I’ve heard that HSR is most efficient at stage lengths up to 600 miles/1000 km. The fact that rail is giving airlines problems at those stage lengths is natural and expected. (The TGV has 93% of the Paris-Lyon market.)

  7. Air travel is on the increase all over the world. You need to look at the passenger miles travelled which is up not the aircraft flight miles which is globally down. This is because airlines are using larger aircraft like the A380 on long haul. http://www.statista.com/statistics/193533/growth-of-global-air-traffic-passenger-demand/
    As for emissions – we need to live with it. Air Travel is only going to increase and whilst there are cleaner alternatives to 100% Fossil Kero – Synthetic Jet from Shell Pearl and bio Jet the amount produced is a small drop in the ocean of demand.
    British Airways are developing a nice bio plant in the UK. It is going to turn Londons domestic waste into 100% bio Jet which is a good story but will only be powering a small percentage of flights. It should be noted that BA receive no tax credits for Bio Jet Fuel as opposed to the huge tax incentives given to land transport bio fuels. Given cars can run on electricity but aircraft can not, the EU might want to re-think that policy. Also interesting to note, no Green political party or organisation is pushing for bio subsidies on aviation fuels.

  8. Sorry John, the Chicago convention just exempts fuel on aircraft moving through member states being taxed. Aviation Kerosene based fuels are subjected to all sorts of taxes depending on the country of operation. For instance the Greedy Spanish are imposing a brand new tax on aviation fuel this year – no doubt to try and pay for all the empty airports they built 🙁 Fortunately the EU finally saw sense last year and removed import duty from Jet A1 but it is wrong to assume there are no taxes.
    My point is that the EU and US give huge subsidies to bio fuel used in transport fuels but zero subsidy to bio mass used in aviation fuels. With the cost of Kerosene collapsing the real cost of using bio fuel for jet aircraft would be prohibitive.

    1. I thought these were taxes on tickets, not international fuels. Some bio fuels require more energy input in fertiliser, etc than they save, so there would need to be a distinction, which makes it more complex.

      1. There are such things a fuel surcharges on tickets. That’s where the fees and taxes are passed along to the customer. And I think Spain is levying a tax because they’re looking for any way the can to raise revenues without violating the austerity regime imposed on them by the ECB.

  9. Fuel surcharge is not a tax – its a bit of a con for airlines to add charges. Sure there may have been a need for a fuel surcharge when oil went up overnight but that was years ago and every airline has the opportunity to hedge their fuel costs years in advance if they want.
    The actual fuels are subject to individual countries tax regimes and can include minerol oil taxes, Energy Efficiency Fund (thats the new Spanish tax), import duty, Sales and Value added taxes. When you think that today Jet fuel costs about US$500 a tonne pre tax there are a lot of added costs the airlines have to pay. Incidentally bio Jet Fuel costs about $2000 a tonne so without a tax incentive or imposed mandate – airlines are not encouraged to use it.
    BA should be applauded for their initiative in London – its a great idea that attacks pollution at two ends of the problem.

    1. Right, it’s not a tax, but it is a way for airlines to pass on higher costs of fuel, whether for the fuel itself of taxes and fees levied on top of the base cost. To an airline it’s all fuel costs.

  10. Te airlines get to keep the fuel surcharges. In other words it is all profit, especially now as fuel prices are collapsing and the airlines are still charging the surcharge.

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