Facts About the Climate impact of Aviation

The debate about flying or not flying is strongly colored by moral features. Why do people moralize about the importance of staying on the ground when air travel accounts for just a few percent of the world’s climate emissions?

Traveling by air can be uncomfortable and crowded and climate-disruptive and… just, really wonderful.

Of course, everything has a price, and how high that price really is has been the issue at the center of a heated debate with various posts. Do the corals appear off the coast of Kenya if you take the flight to watch them? Is the business in the northern parts of the world affected if it becomes more expensive to fly there? Is the climate effect eliminated if all domestic flights are fueled with biofuels? Is the working class tormented unnecessarily much if it can no longer buy cheap tickets for 99 bucks? Is it even a human right to fly wherever you want and how often you feel like it?

One thing that has puzzled a lot of people in this debate is the fact that aviation accounts for a relatively small proportion of climate emissions, compared to the vehicle fleet on the ground. Of the total emissions in the world, the transport sector accounts for 14 percent according to IPCC estimates from 2010. Of these emissions, aviation accounts for 10.6 percent (of which international flights account for 6.5 percent), which means that aviation accounts for 1.4 percent of the world’s total emissions. It should be compared with road transport, which accounts for 72.1% of all transport emissions, or 10% of the world’s emissions.

Yes, let’s be aware that air traffic has increased since these figures were reported (2010) and that real emissions are probably some percent higher, but the levels are still low relatively speaking. Taking into account that people in wealthy countries travel more by air than people in low-income countries, the impact of the wealthy countries’ aviation on the climate increases by a few percent. Taking into account the forecasts that indicate that flying will double in the next two decades, it will be even more so. But still: what’s the thing? If the goal is to reduce its climate impact, should we talk about putting the car in instead of staying on the ground?

The technological development in the aviation industry is not what it should be

The realization that fossil fuels have a negative impact on the climate has increased the pace of innovation in the automotive industry over the past decade. Today, lots of cars, trucks, and buses are rolling, which emit less thanks to being more fuel-efficient, using renewable fuels or running on electricity. There is barely any parallel in the aviation industry.

Over the past decade, aircrafts have become lighter and have received winglets on the wingtips to reduce consumption (such as the Airbus A320 Neo) but are basically built just like before. The major improvement has been made through engines that are more fuel-efficient than before (like the GE9X), but the savings nevertheless will be no more than 5 and 15 percent, no more. Compare that to cars that have cut fuel consumption in half in ten years (for the BMW 5 Series this is a change from 0.66 l / 10 km and 176 g co2 / km 2008 to 0.2 l / 10 km and 49 g co2 / 10 km 2018 ).

Several companies have been working actively to optimize flight routes through green departures, straighter flight routes and green approaches, which has helped to reduce fuel consumption. However, there are no huge savings. Statistics clearly show how emissions from road traffic have decreased in recent years, while emissions for air travel have increased.

Low-cost airlines like Ryanair and Norwegian are happy to tell you that they have green aircraft fleets based on the fact that they use newer aircraft with more fuel-efficient engines than their competitors. This is true, at least in terms of emissions per passenger-kilometer. But since they are still using fossil fuels, it is deeply misleading to speak of the fleet as “green”. The climate impact of low-price companies is increasing as companies grow and today, emissions from a single company can be on par with a smaller nation. (This year Ryanair’s emissions were almost as great as Cyprus’s emissions!)

The climate impact of aviation is disproportionately large

To reduce the risk of major, irreversible climate change, each of us must not emit more than one ton of greenhouse gases. That’s the number of emissions the planet can absorb per person each year. Today wealthy countries are just over ten tonnes per person per year.

A trip to New York from Europe generates about 2.5 tonnes of emissions. A trip across the Atlantic thus consumes two-thirds of the annual budget of 4 tonnes, which WWF states we must keep within 2030. A long flight by air is thus the single most climate-impacting activity we can undertake, given the amount of emissions in a short period of time.

In addition, for long flights, the high altitude effect is recorded. Combustion of fuels at march height for most long-distance journeys (30,000 feet / 10,000 meters) is estimated to double the climate effect, compared to if combustion occurred at ground level. However, the statistics on fuel consumption that are used to calculate the climate impact of aviation are ignored, which means that the real effect is greater.

The climate-impacting high altitude effects occur in traffic of more than 8000-9000 meters. Since many short domestic flights take place at lower altitudes (BRA flies at 6000-7000 meters) the effect is not as great as longer flights.

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